Sunday, 27 December 2015

Ken Thompson's "Sceptical Gardener" and permaculture

I have just been reading one of my Christmas presents, Ken Thompson's Sceptical Gardener.  I am prepared to forgive him for writing for the Telegraph but his dismissal of permaculture is a little perfunctory.   While understanding his conservative audience, maybe a little more circumspect research would have given him a few more insights. 

He makes much of looking at several websites.  I realise that today’s students are encouraged to use the internet as a useful tool.  However, I always taught that going to the original peer reviewed published research was a much better way of exploring ideas. 

While Bill Mollison’s book “Permaculture a Designer’s Manual” is a little out of date being published in 1988, it is still a research tool of choice when considering permaculture.  The web sites are eclectic and reflect permaculture's inclusiveness.  It is not necessary to agree with most views on these sites because they are just individual interpretations of the basic principles in the Manual. 

Ken Thompson seems to equate permaculture with forest gardening and then dismiss it because it is not a valid method of producing enough food to feed the world.  Totally agree that forest gardening is not a panacea for all the world’s problems; however it is not a significant part of permaculture.  I would suggest, however, that good design of new forests would produce a lot more resources than the monocultures do at present. 

Although there is little mention of forest gardening in, “Permaculture a Designer’s Manual” it is easily integrated into the framework as are other methods and philosophies.  The experimental works of Martin Crawford and Patrick Whitefield have indicated that productive forest trees can be designed into a landscape in order to produce useful crops.  However, this is just one, and the most remote, of five areas or zones that permaculture designs make productive for human food and materials sustainability. 

Unfortunately for someone that wants to take permaculture seriously, it does seem to have been hijacked by the more extreme members of the environmental movements.  Biodynamics, lunar gardening, new wave philosophy together with American survivalists all seems to include permaculture type concepts in their literature.  However, these ideas are not permaculture and neither is forest gardening. 

So what is permaculture?  It is an overarching landscape design procedure.  It takes the fundamental factors of living systems and designs them to achieve the most productive and sustainable and abundant outcomes that a particular landscape and its topography can provide.  It seeks to control elements like water and nutrient availability through low appropriate technology.  It is pragmatic in the extreme.  It celebrates what works.  It is based on a careful consideration of landscape potential together with intense observation. 

No matter where it has been tried throughout the world – Australia, Ethiopia, China, Jordan, Morocco, United States, Britain – it seems to be an effective way of producing a very sustainable, low fossil carbon method of agriculture and horticulture. 

It is a method of mitigating the effects of environmental extremes like flooding and drought and turning what seems to be impossible growing environments to advantage.  It seems to work both at the macro and micro level.  I have adopted many of the principles of permaculture in the small landscape of my allotment and, although it is still early days, it would seem to be achieving what I want it to do.  I don't have a slug problem but I certainly have a lack of ducks problem. 

My permaculture design certificate.
Although I was very sceptical, like Ken Thompson, I decided to take the permaculture design course just to have a more in depth understanding of its principles.  The more I learnt and the more I watched the video evidence the less sceptical I became. 

Permaculture reminds landscape designers to consider climate, aspect, water, nutrients, dwellings, access, energy production, recycling, productive fauna and flora, and materials such as clay and gravel.  It melds all these elements into a synergetic system which is designed to meet the reasonable needs of people. 

So it’s a little more than planting nut trees Ken Thompson.    

Wednesday, 23 December 2015

Christmas vegetables.

I went up to the allotment today to get the Christmas day vegetables.  Actually, they will probably last us into the new year. These are the vegetables I got either out of the ground or from the store shed.  I had to get them today because it will take me all tomorrow to prepare them.  That and wrapping presents. 
Vegetables for Christmas.

So we have some kale, Brussel sprouts, swede, red cabbage, leeks, celery, celeriac, pumpkin, squash, shallot, garlic, elephant garlic, oca, carrots, onions and parsnips.  Some of them are a bit moth eaten but that does not alter the taste.  I might get some beans and peas out of the freezer too. 

Happy Christmas and a very good, fruitful year.

Sunday, 20 December 2015

Harvesting oca and sieving the compost.

The oca has been cut back by the frost and was ready to be harvested. 
Oca plants Oxalis tuberosa  

I am storing them in an old paper bag that my red and white currants came in.  The bag was still quite serviceable and would keep the oca in fairly good nick for the winter. 

I am eating oca quite regularly now, including them in soups, curries and stews. 

Paper sac for the oca tubers.
They were just forked out and I didn't take much care to remove all the little tubers. If the little tubers grow next year, they will have to compete with the potatoes that are going to be planted here. 

Digging up the oca.
These tubers were red but you can get them orange and yellow.  The tubers were not very big and although some were about ten centimetres long, most were barely one.   You have to accept that the tubers are this size and be prepared to harvest them anyway.  The size does not affect their taste.

A thick layer of woody shreddings was put around the oca during the summer and, as you can see, it has all rotted away now except for a few bits here and there. 

The largest tubers
This oca plant had the most and the biggest tubers.  They are quite long - up to 10 centimetres and look a bit like pink fir apple potatoes.  However, most tubers are small and can be less than a centimetre in diameter.  Although the tubers are not anywhere near as big as potatoes, they are still an interesting and valuable addition to the dinner table.  The tubers can be scrubbed clean and cooked without peeling.  Slugs, snails and other tuber eating soil animals do not seem to bother at all with oca and the tubers are usually unblemished. 

The last plant harvested
They are quite easy to fork out and harvest.  The paper sac was about one third full when I had harvested all eight plants.  A handful of tubers will be kept to plant for next year's crop but the rest will be used in the kitchen. 

Taking out the oca left me with a strip of garden that was not covered with green manure. It would be quite difficult to get any green manure seed to germinate now even though it is unprecedentedly warm.  Furthermore, I have run out of green manure seed.

I also had a pile of oca tops that needed to be composted.  All the compost bins were chocker block and I could not fit anything else into them unless I started to empty them. 

So I was in a bit of quandary about what to do.  It was a compost turning day today and I thought that I would start to sieve out the compost while turning it.  I could see if there was enough well rotted compost to put along the strip of  ground that the oca had been harvested from.  It would cover the top soil and protect it from the rain while adding a little nutrient through leaching.  I could either spread it across the top of the new potato bed or dig it in during next spring.  The top soil here has not been composted or manured  because the oca were still growing; so I needed to add something to the soil particularly as this part of the allotment was not cleared of perennial weeds until the end of May.  Sieved well rotted compost seemed to be the answer. 
My trusty bread tray sieve.
The bread tray sieve was used to separate out the larger pieces of compost that could be returned to the bins.  The smaller well decomposed compost could fall through the holes and into the wheelbarrow.  During the time the compost is being turned, it reduces in volume and sinks down in the bins.  This means that fresh organic matter can be added to the top.  And that's what I did.  This causes a problem when it has to be sieved because there is compost at different stages of decomposition.  The bins should be filled at the beginning of the turning cycle and then no more organic matter added. 
Still, the bins produced some very good rough compost. 

Compost being sieved
Most of it passed through the one inch mesh of the bread tray.  What was left in the sieve was returned to the compost bin.  I got about four or five barrow loads of compost from just two of the compost bins and this was put onto the new potato bed. 
The compost was turned every two days for about one month. 
Some good rough compost.
Although I half filled the large green bin with the left overs, I had room to add the oca tops.  So the cycle continues. 

Saturday, 19 December 2015

What to expect when you take over an allotment.

Now that we are coming up to the new year, lots of people will be thinking about getting an allotment. Unfortunately their idea of an allotment is beautifully dug, friable soil and a little shed in the corner. If you are extremely lucky, then you will get one like this but most allotments are full of perennial weeds and junk. Although old lags like me would like to help as much as we can, we have our own allotments to cultivate. You will have to do almost all the work yourself. You will probably need to get a shed and transport it to the allotment. If you want a greenhouse then you will definitely have to find one yourself.

Make a plan for the allotment - and keep to it.
This was one of the allotments I took over in 2010.  I gave it up when I moved to a new site.
You will need to be prepared to do a lot of work for a couple of years to make the allotment  productive.  Lots of perennial weeds will cover the plot and you will need to be able to identify nettles, mare's tail, bindweed and couch grass and their rhizomes.  Rhizomes are underground stems that can regenerate the plants from tiny pieces - if you let them.  These will have to be removed no matter which method of cultivation you choose.  Covering the soil will relatively quickly clear the tops of weeds but it will not remove rhizomes unless you leave the cover on for about two years.  Even then you will get invasion from the sides. 
I would not use carpets to cover the soil because they attract rats.  There was a big colony under the carpet in the photograph above. 
Mostly bindweed and couch grass rhizomes.  There are a lot of nutrients locked up in these rhizomes so don't throw them
 away or burn them.
Most plants can be micro propagated from a few cells in a test tube so these rhizomes have a flying start if you leave them in the soil. 

So you will have to dig.  START DIGGING AT AN EDGE. 

If you are going to adopt a no dig method then you still need to dig the allotment to clear off the perennial weeds.  No dig does not mean an untidy allotment. 

The best digging technique is to double dig removing rhizomes as you go.  If the rhizomes are left out in the open, they will dry after about three to four weeks.  Then they can be composted.  

The amount of weeds will indicate how fertile your allotment is. 
I split this allotment into two with some string.  A trench was taken out this side of the allotment and put onto the soil on the other half.  I worked down this side and up the other digging trenches and filling them with clean topsoil.  As the subsoil is usually less fertile than top soil, it is best not to bring this to the surface.  But subsoil can be improved a lot if you add compost, manure or other fertilisers. 

As you can see, this allotment was not very fertile and was very waterlogged for about three months of the year.  It had a large colony of rats at the back and there was a lot of junk left scattered about.  The soil was mostly a sandy clay with very little organic matter mixed in.  As I had my other allotment on the go and it was highly productive, this one was given up and the bottom was turned into an environmental area by the allotment committee.  As I said you can't rent out a pond to cultivate. 

My first allotment in February 1982. Eventually this allotment came third in the Wolverhampton allotment
My first allotment I got in December 1981 and I double dug it, skimming off the grass and nettles burying them in the trench.  I would be wary of burying couch grass unless you know what you are doing. 

If you can find a gardening course that will introduce you to what to expect when taking on a new plot, then I would encourage you to take it.  The RHS level 2 diploma is quite good but does not really give you a realistic impression of how much work is involved. 

The reason why most people give up is because they don't realise what allotmenteering involves.
It is hard work. 

If I have put you off then probably you shouldn't have considered taking on a allotment in the first place.  However, if you still want to give it a go then I think you will enjoy the experience. 

Don't take too much land on especially if you have a full time job and a family.  I think that gardening is a lovely activity to do with the whole family, but it is not everyone's ideal pass time. 

I took on my new allotment in 2013.

I did cover part of the new allotment in carpet, although carpets attract rats and mice. However, they do clear the tops off quite quickly.  I did not clear the cage away until 2014.  It is where my peach greenhouse is now. 
I used carpets because they were already on the allotment.  Try to use all the resources already on the allotment because this can save you money. Eventually, though I had to clear the carpets away and took them down to the council waste disposal site. 

None of the weeds were burnt.  All of them were either composted or buried deeply in trenches.  In this way I kept all the nutrients, trapped in the weeds, on the allotment and recycled into the allotment soil.   
Covering the soil does not mean that you don't have to dig.  Once you get all the perennials out then you can adopt the no dig method.  This is the allotment in 2014.
My new allotment does not look like this now.  This allotment came fourth in the Wolverhampton allotment competition in 2015. 

Allotment in 2015 from a similar angle.

It has taken me three seasons to get the whole of my new allotment to a standard I think is acceptable.  Now I just have to improve the soil. 

Friday, 18 December 2015

Sticking soil particles together.

The parts of the soil that are produced by the erosion of bedrock give the soil its basic characteristics such as its texture and pH but the gardener cannot easily change these properties. 

However, gardeners can influence the amount of air, water and organic matter that go to form the soil's structure.  If water and air filled pores are too small then the soil becomes waterlogged in winter and solid in summer.  If the pores are too big then water drains away too quickly and the soil dries.  Dry soil is damaged  by wind erosion of small, light particles. 

As roots need oxygen to respire and produce energy to grow, waterlogging will be detrimental to root extension and may even result in root death.  Water is a vital constituent for photosynthesis and needs to be provided in sufficient quantities. 

The rapid drainage of water from the soil will cause leaching that the production of nutrients from decomposition cannot keep pace with.  It may also be difficult for the addition of man made fertilisers to replace lost nutrients.  Small, light soil particles can relatively easily be removed in the mass flow of water.  These are the clay and organic matter particles that have charged surfaces and contribute to the retention of nutrients in the soil. 

Surface runoff, particularly from hard surfaces, will also exacerbate the loss of clay and organic matter from the top soil.  Where I have trapped surface run off, and along the path where puddles form, you can see a fine layer of soil particles covering the surface when water has evaporated.

To prevent this from happening we need to regulate the size and shape of the soil water filled and air filled pores.  A more varied range of sizes means that both water and air can be trapped effectively providing these essential resources for soil life. 

We need to stick the soil particles together. Soil glue is produced from a large number of different sources.  Decomposition of vegetable and animal organic matter produces a sticky gel, which is quite difficult to remove from the hands and leaves a stain for several washings. 

In order to obtain sustenance from organic matter both bacteria and fungi secrete enzymes into the soil matrix.  Not only are these enzymes sticky themselves but they form sticky substances when they break down organic matter.  These enzymes can stick to both clay and organic matter and continue to function for some time.  Both bacteria and fungi also secrete sticky mucilage as a protection from predators. 

The larger soil fauna, like nematodes, earthworms, slugs and snails secrete sticky mucus which is quite difficult to wash off the hands.  I know cus I've been slimed.  I always find it remarkable that, even though these animals produce a sticky mucus, they are remarkably clean animals. 

The excreta of most animals contain sticky mucus type compounds and these are left on the surface of the soil if not within it. 

Plant roots secrete sticky gels and organic compounds.  This can be seen to most dramatic effect under tussocks of grass.   There always seems to be a beautifully structured, friable top soil enmeshed within the adventitious roots.  This soil structure can be quite different from the surrounding soil and be full of worms and other small animals. 

After the complete decomposition process, the final product is humus.  This is made up of organic compounds that are very difficult for the bacteria and fungi to break down.  It is sticky and forms a  thin layer over soil particles. 

All of these sticky compounds will aid the production of a wide range of different sized pores by sticking soil particles together.  With this variety of different sized pores both water and air can be retained in the soil.  Small and light particles can be trapped and the mass flow of water slowed.  Reducing the mass flow allows the water to soak throughout the soil profile; nutrients to be taken up by plant roots rather than leached and allows nutrient production by decomposition to keep up with nutrient loss. 

Compost and manure contains lots of these sticky compounds together with the organisms that produce them.  Why would you not add them to the soil? 

Man made chemical fertilisers do not contain these sticky compounds or the soil organisms that make most of them, so they do not help to produce a good soil structure. 

Wednesday, 16 December 2015

Turning the compost.

I turned the compost bins again today.  I think that it is noticeable how much slower the decomposition is than during the summer.  However, it was a balmy 130C all day today and this is unprecedented in December.   So what is slowing down the rotting down process? 

I'm not sure. 

I am still composting couch grass Elymus repens,  mare's tail Equisetum arvense, and bindweed Calistegia sepium  and these decomposed relatively quickly during the summer and autumn. 

Regardless, I am making some very good rough compost that will be ideal for adding to the soil in the allotment.  I will give the compost another two weeks or so before using it, turning it every two days or so.  It will be sieved through the one inch mesh bread tray before it is used and I will put anything that doesn't go through the holes back into the compost bins.  There are some blackcurrant and redcurrant roots that need to be cut up because they are not decomposing very quickly. 

I am adding neat comfrey liquid from the comfrey butts behind the large shed because I have no other use for it at the moment. 

I will be using the comfrey to make some more inoculated charcoal. I marinate barbeque lump charcoal in comfrey liquid for about three or four months and then crush the lumps with a bull hammer before spreading on the soil.  There are several reasons for using charcoal which I have talked about before.

James Barnes, head gardener at Bicton during the Victorian era, used charcoal in his gardening.

I made some charcoal earlier in the year fairly successfully but put this in the compost bins.  As I usually bury wood as a trench Hugelkultur, I don't really have any wood to make charcoal out of.  I was going to see if I could use the couch grass, mare's tail and bindweed rhizomes but they make such good compost, I don't really want to use them. 

I might go around the allotment site and see if anyone has spare wood that they don't want.  I am already taking people's weeds to compost!

The M26 apple rootstock has come and I have healed them in at the allotment.  I will pot them up during the week, just in garden soil.  It is much easier to bench graft than to try to do it when they are in the ground.  Also, I like to give them a little protection during their first winter and leave them in the little peach greenhouse.  They also need to be protected from my big feet because I have now trodden on three of my grafts and broken them.  The one I am most upset about is the Norfolk Pippin. 

To avoid this I only plant out if I have the posts and wire to train them to. 

The Bardsey, Coeur de Boeuf, Ellis Bitter, Sturmer Pippin, Christmas Pearmain; Mosses Seedling; Court of Wick; Gala, and Kidd's Orange scions have not come yet and I will not be expecting them until March. 

However, the Lapin's cherry has come.  It is a one year old tree but is not feathered.  The rootstock is Gisela 5.  I will head it back and prune it as a fan - probably.  I may, however, prune it as an espalier.  Fans are a little more fiddly.  I am going to plant it where the runner beans were last year. 

I am digging out the little ditch next to the trackway mainly to remove the weeds.  I am filling the ditch with stones and covering them with a thin layer of woody chippings, just for aesthetic reasons. 
The idea is to trap water, slow it  down and letting it soak into the allotment soil. 

The bought sweet pea seeds have not done very well.  I have about a 20% germination rate and this is atrocious.  I threw some of my own sweet pea seed in a few pots  thinking that they would not do well, however they have all germinated and I have more than enough to replace the failures. 

Next year, I will not buy any sweet pea seeds, just keeping and sowing my own.  I am slowly transplanting my seedlings into root trainers.  I will leave them in the greenhouse until I plant them in the ground during March next year. 

Sunday, 13 December 2015

More misconceptions ?

Dowding says that it is untrue that all soil nutrients are water soluble and can be leached by the rain.  I think that he is a little confused here.

Only nutrients in solution have been observed entering plant roots.  If they aren't soluble then they aren't nutrients. 

None of the nutrients exist in the soil as elements but are always bonded with other elements in molecules.  When the soluble molecules dissolve they dissociate into positively and negatively charged particles called "ions". 

These positively and negatively charged particles can stay in solution or associate with the opposite charge on the surface of organic matter or some clays.  This is called nutrient adsorption and forms what can be called an active nutrient pool.  Nutrients can be adsorbed or dissolved depending  the concentration of nutrient ions in solution and the soil solution pH.

So the plant can access these nutrients by altering the pH of the soil solution.  Plants do this by secreting organic acids from their roots.  When acids dissolve in water they also dissociate into positive and negative ions and one of them is always a proton - a hydrogen ion.  They can also pump  protons out of the root using energy.  Protons are little jobs that can get between the nutrient ions and organic matter  popping off the nutrients and returning them to the soil solution by replacing them. 

Getting nutrients into the root is not an straightforward process.  Some nutrients enter down a concentration gradient,  where there is a higher concentration in the soil solution than in the root cells.  They have to enter root cells through special pores in cell membranes.  Other nutrients need to be pumped into the root cells using energy. 

If you alter the concentration of nutrients around the root by adding man made fertilisers there may be a net flow of water out of the root due to osmosis.  This will damage the root and  may be the origin of the "root burning" misconception.  However, even when I used National Growmore, I  never saw "root burning".  Adding fertilisers, whether organic or man made, is an expensive business so I never put very much on. 

I presume it would be more likely with the delicate roots of seedlings but with the composts I use - home made or bought - it is never a problem. 

I do add lots of manure and compost.
There may be a problem with fresh manure because of the concentration of urine and the production of ammonia, but this is not a problem if you allow urine and ammonia to be leached out, leaving the manure  to rot down for a while.  This is why it is useful to have the manure storage at a high point on the allotment garden.  .  A slow leaching will allow the nutrients to become diluted and avoid concentrations around the roots.  The urine and ammonia will flow down the slope and be made available to vegetables while it is moving through the soil in the soil water. 

Cations are positively charged and anions are negatively charged ions.  The cation exchange capacity of the soil can be seen as a measure of the soil's ability to store and  pop off plant nutrients. In other words its fertility.

Any nutrients dissolved in the soil solution can be lost due to mass flow of water through the soil pores - what we call leaching. 

It is true that some nutrients, like phosphorous, have very low solubility and that is probably why the region around the root is usually deficient in this nutrient.  Phosphorus from the active pool is slow to dissolve and this leads to depletion. 

Phosphorus can also be combined with elements like calcium and aluminium. Calcium phosphate (bones and a small percentage of egg shell)  is not very soluble and aluminium phosphate is not soluble at all.  Although calcium phosphate is slow to dissolve, it is soluble and does contribute to the nutrient pool. 

So to reiterate; all nutrients are soluble and all nutrients can be leached albeit some slower than others. 

If nutrients are adsorbed onto the surface of clays or organic matter then they are a little more resistant to leaching. 

Manures and composts contain nutrients which are locked up in large organic molecules.  Organic chemicals in Chemistry just mean those with carbon in them.  While they are locked up in the organic molecules they are inaccessible to plants.  However, these large organic molecules can be used by bacteria and fungi to produce their mass and energy.  While this is happening  nutrients are released into the soil solution or adsorbed onto charged surfaces.  This is called mineralisation. 

Adding man made fertilisers bypasses this process. 

Saturday, 12 December 2015

Trying to avoid generating new misconceptions

It is amazing how you can generate misconceptions, especially, as in my case, when you don't fully explain what you mean. 

Manmade chemical fertilisers do not necessarily degrade soil.  However they replace essential organic matter in the form of composts and manures which are essential for maintaining soil life and structure. 
I remember seeing a farmer on the television complaining that when he tried to plough in his straw stubble rather than burn it,  it had not decomposed even after one year. 
He held some of his soil in his hand to demonstrate that the straw was still there.  From what I saw the soil was no more than dust with little organic matter and virtually no life within it.  He had been using man made chemical fertilisers for years.  No wonder the straw did not decompose.

We have been throwing away vast amounts of local organic matter - the leaves swept up in towns and cities, shredded woody material, our vegetable peelings, our garden waste- that could easily be composted and used as fertiliser.  Although we are starting to utilise this material now rather than burning or adding it to land fill sites,  an awful amount is still wasted. 
Many years ago I wrote about how nutrients from far off lands were being imported to this country in the form of food plants like citrus fruit, tea and coffee.  We ate them and then flushed them into the sea through the sewers.  If we left the nutrients in the countries that need them allowing them to produce enough food for themselves rather than export it to us then there may be a little less starvation in the world.  Also, we need to consider whether we can rejoin the natural recycling of humanure rather than just flushing it into the sea and contributing to dead zones. 

Man made fertilisers do not necessarily degrade the soil, however they are expensive, based on oil technology, use vast amounts of energy, have to be transported large distances and bypass the necessity of adding organic matter to the soil. 
Although we can grow plants by hydroponics in sterile factories, I still would rather grow and eat a moth eaten organically home grown vegetable.  Not because it tastes better or because it has more vitamins or it has more fibre or because it doesn’t need to be transported vast distances or it’s  not covered in unwanted pesticides or because it is not overfull of nitrogen produced by the Haber Bosh process but just because it is a wonderful thing to be able to do.  Fresh is best.

Internal Consistency in Gardening

It is not consistent to attempt to dispel myths by producing more yourself. 

One of the most powerful concepts of science is internal consistency.  The laws of science operate in whichever science is being studied and consistency must be maintained within a science. 

So how does this apply to my gardening? 

Dowding suggests in his book "Gardening Myths" that digging is not necessary in a vegetable garden.  He is making the same assertion as Bill Mollison did in his book, "Permaculture: A Designers Manuel" written in 1988.  I'll go along with this.  I will avoid digging, however I reserve the right  to dig when I feel it is necessary. 

They both say that digging causes damage and death to soil inhabitants such as worms, beetles, bacteria and in particular mychorrhizal fungi and it also causes a loss of existing soil structure. 

Now to be internally consistent this should apply whenever digging is used. 

I have been turning over the compost in my compost bins today.  I try to turn the compost every two days as Geoff Lawton suggested in the Permaculture course I have just completed.  While the compost is being turned, I shake it out well with a fork.  After about ten days the constituents of the compost start to fall apart and turning becomes progressively easier. 

The compost is full of wildlife especially various types of worms.  However, there are also lots of beetles, slugs, snails, millipedes, centipedes and woodlice.  All of which are helping with the process of decomposition. 

As we have decomposition, there must be both bacteria and fungi mixed in with the compost.  Indeed fungi mycelium can be seen particularly in the woody material and tree leaves. 

So, if digging damages organisms in the soil, why  doesn't it damage them in the compost when it is turned over? 

Dowding says that there is a loss of organic matter from the soil as carbon dioxide if it is dug.  This is consistent with the reduction in volume of the compost as it rots down.  But, how is the carbon dioxide produced in the dug soil if there are no bacteria and fungi decomposing the organic matter? 

Bacteria and fungi use the carbon in organic matter to produce their mass and energy.  The final product of both these processes is carbon dioxide and water.  (For the scientists: catabolism when they are alive and anabolism when they die.)

Carbon dioxide is not produced by magic.  There is a biochemical process that can be described to explain its appearance and this involves the presence of bacteria and fungi. 

I would really suggest that bacteria and fungi are not killed off and digging does not sterilise the soil.  I wish it would because it would be an easy way of getting rid of club root and white rot fungi. 

So if club root and white rot are not killed in the soil by digging is mychorrhizal fungi?  I doubt it, but I still like to add mychorrhizal fungi spores when planting out fruit and vegetables.  The more spores there are near the roots the more likely they are going to be infected by mychorrhizal fungi. 

The same people that are telling me mychorrhizal fungi are killed due to digging then tell me it is not worth adding mychorrhizal spores because they are ubiquitous in the soil.  This is not consistent. 

There is some well documented data that suggests that there are less worms in cultivated soil than in  lawns and pastures.  However, beware of correlation.  Is the cause of this cultivation or are we just seeing a habitat preference?  Identifying cause and effect is not always that easy. 

There is no doubt that some worms are killed during digging.  The silly myth that one half of a worm will regenerate if it is sliced in two is false.  What you get is two dead halves.  There is also evidence that worms do not like disturbance so avoiding digging whenever possible is probably a good strategy if you want to encourage worms into your garden. 

Lets see if there is internal consistency with soil structure.

I would say that it takes about three to four weeks of turning every two days to make some good friable, well structured, open compost that looks very like good soil.  So if turning the compost does not destroy structure but, on the contrary, improves it greatly, why does digging destroy structure in soil?  I don't think it does.  It is the loss of organic matter that causes collapse of soil structure. 

There are many good reasons for not digging the soil but I don't think that killing soil organisms and destroying soil structure are two of them. 

Thursday, 10 December 2015

Yet more myths and legends: misconceptions in gardening.

Really I shouldn't get upset when people like Dowding say they feed plants.  Indeed the definition of food is not all that clear even in science.  However, it does lead to some interesting misconceptions. 

Plants use the energy from sunlight to convert carbon dioxide and water into molecules that can provide them with energy and mass.  They make their own food.  The process is called photosynthesis and plants are referred to as photo autotrophs.  They also need relatively tiny amounts of elements like nitrogen, phosphorous and potassium.  They combine these elements with the molecules formed from carbon dioxide and water to make all the compounds they need to survive. 

Animals can't do this so they eat the chemicals that plants make.  They are called heterotrophs.  (They can also get these chemicals from other animals that have eaten plants.) These chemicals are usually called food. 

Fungi can't photosynthesise and need to get their energy and mass from chemicals produced by plants.  They are heterotrophs too.  Bacteria get their energy and mass from a number of different sources.  They can be heterotrophs, however some  are autotrophs.  Some can utilise energy from the Sun and others can utilise energy from chemicals.  These include the decomposers. 

Why is this important for gardeners?  Well understanding this means that you can appreciate what is happening when you add fertilisers and manures and it will help you to understand what is happening when you are making compost.

 So you can't feed plants in the same way as you can feed animals and fungi. 

You can supply chemicals that contain nutrients like phosphorus, nitrogen and potassium to the soil where they can break down into soluble salts which can be taken up by the roots of plants.  However, I find it difficult to describe this as, "feeding plants." 

Also there is a limit to the amount of these nutrients needed by plants and their rate of uptake.  Plants will need them when and where they are actively growing. 

Adding chemical fertilisers bypasses the normal pathways of decay and decomposition.  These soluble salts dissolve relatively quickly and  are readily taken up by plants to enhance growth.  However, this is not really sustainable because it relies a great deal on fossil fuels to generate these fertilisers.  Also it leads to soil degeneration.  Chemicals that stick soil particles together like humus are lost and organisms, like worms, fungi and bacteria that produce sticky mucilage do not have food to survive.  Soil structure begins to break down and eventually yields are considerably reduced.  Less water can be stored in the soil and it becomes very dusty and easily eroded by both wind and rain. 

Nutrients are stored in the soil by being attached to clay and organic material.  Both clay and organic material are light and easily removed by wind and water leaving the heavier sand and stone which store much less nutrient and water.  This we call soil degradation.

Compost and manure in bays made from pallets
Providing nutrients appropriately is achieved much more efficiently by adding organic material such as compost or manure.  Composts and manures add much more than nutrients to the soil.  They add material in different states of decomposition and a community of decomposer organisms and their predators.  Composts and manures also add soil particle binding chemicals that improve the soil structure, increase air and water filled porosity, reduce bulk density and produce a very friable soil. 

Manure and woody chippings are both valuable organic matter.
Some people suggest that there is a limit to the amount of organic matter that can be added to the soil.  If there is then I have not found it yet.  I am adding copious amounts of compost, manure and woody chippings throughout the year and there does not seem to be any depletion of yield. 

Both fungi and bacteria excrete enzymes that can be stabilized by clay and organic material and continue to break down composts and manure to produce plant nutrients.   Decomposers produce mucilage which is sticky and binds the soil particles together and prevents them from being blown away by the wind. 

Compost bins make good compost if you turn the compost regularly but they rarely heat up
very much.
It is true that there is much less nutrient in composts and manures than there is in the same volume of inorganic fertilisers.    However, plants need a tiny amount of these nutrient compared to that of carbon dioxide and water.  We are doing well providing plants with carbon dioxide from ancient carbon when we burn oil.  So really the limiting factor is water. 

Composts, manures and other organic matter also help to retain water in the soil.  They are sponges that soak up excess water and release it slowly to make it available to plants.  A covering mulch of organic material will reduce surface evaporation considerably.  It will also help to prevent wind and rain erosion. 

Really, in the UK we should not have to water plants outside, however if we do water then we should give the water when the plants are actively photosynthesising.  That's when they need it.  This will be when it is light and the best time to give it is in the morning so that it will be available to use during the daylight time of the day.  (A day is 24 hours.) 

It is true that anything that was once alive will decompose and form a good compost.  Wood rots very easily if it gets wet.  I put up to 15cm long and  5cm diameter cut branches in the compost.  First they change colour to a very dark brown.  Then they go very brittle and can be easily broken.  Then they become very friable and can be pulled apart by hand.  That's why I don't like to use wooden edging for the vegetable beds. 

As Dowding says, perennial weeds such as couch grass make very good compost. And I agree with him. They look very unpromising in the photographs below but they change colour to a very dark brown after a week and start to break apart after about ten days. Bits of plastic, metal, glass and stone fall out of it, and by three weeks you cannot tell what the compost has been made from.  At one month it is good enough to sieve and put onto the vegetable beds.  Although this looks very woody, there are still  nutrients locked up in it. 

Mixture of stinging nettle, couch grass and mare's tail being composted. I dried it very well
before composing it.

I added comfrey liquid and turned it every two days to produce a very good compost. I'm doing
the same with the perennial weeds we got off the new car park.
Cotton and wool (good sources of nitrogen) in the form of sweaters, jumpers, trousers and shirts all rot down.  In Victorian times farmers used a lot of rags as a fertiliser but they did not want them washed! 

Leather shoes, belts and bags decompose very slowly.  The gardeners at the Alternative Technology Centre in Wales told me that old horse saddles and tackle rots down particularly slowly. 

Cardboard rots down remarkably quickly and so too does paper shredded or not. 

When we had horse manure delivered free to the allotment site, some allotmenteers would separate out the horse hair, rejecting it and leaving it to one side.  Hair is about 90% keratin.  Keratin is a protein and proteins contain nitrogen.  I collected the hair up, thanking those that sorted it out for me, and added it to my soil. 

Dowding says correctly that both citrus peel and rhubarb leaves can be added to the compost heap.  They both rot down very quickly.  Citrus peel contains a natural pesticide called d-limonene, however the pesticide can only be made from very concentrated citrus oil.  It is an insecticide and does not affect the decomposer worms, fungi and bacteria in the compost heap.  They will rot it down just like all the other organic chemicals in the heap.  Rhubarb leaves contain oxalic acid which might cause us a problem if we eat too much of it but does not present a problem for worms, fungi and bacteria.  Its just another source of carbon for them. 

Woody chippings used as mulch.  They decompose slowly over a year and there is no
noticeable nitrogen immobilisation. 
The growing points and small leaves at the tips of stems are where most nutrients obtained from the soil are being used.   This is where the plants will use most energy and resources to grow.   

Where does most of the energy and resources come from?   

Well from leaves that are no longer growing.  The large moth eaten leaves near the base of the plant.  These are the photosynthesising powerhouses that fuel growth in the rest of the plant. 

Yet these are the leaves some people remove from their tomato plants. 

Leave your tomato leaves alone. You will get a lot more tomato fruit. 

Saturday, 5 December 2015

More myths and legends: misconceptions in gardening

I have seen people take off weeds together with top soil, bag it up and take it to the local municipal waste disposal site.  They dig but do not add anything to the soil and plant and sow into what I would imagine is very unpromising soil.  However, they seem to get a really good crop of vegetables.  And this continues over several years. 

I don't know how they do this unless they surreptitiously creep in and spread artificial fertiliser around.  It may, however, suggest that soil is more resilient than we imagine and can deal with human interference better than we expect. 

Reason would suggest that you have to replace what you take from the soil.  However, plants take very small amounts of nutrient from the soil.  A great deal of which is replaced by the weathering of rock and stone already in the soil. 

Also, plants don't want to die.  They don't die just to spite us.  They will make great efforts and struggle to survive wherever they grow. 

This is why I take little credit for the vegetables that grow on my allotment.  They do all the growing; I just try to make it as easy for them as possible. 

So what is my point?  There are some pretty amazing misconceptions out there but most of them are harmless and amusing.  Plants grow regardless.

Does it really matter if we put egg shells on our compost? 

I don't think so. 

Whether they decompose or just fall apart because of weathering does not really impinge on my gardening at all.

However Dowding doesn't  seem to understand the role of nitrogen fixing bacteria in legume root nodules. A slightly more important misconception, that does affect my gardening.  He quotes Chris Beardshaw on "Gardeners' Question Time." when he says that most of the nitrogen fixed by bacteria in the root nodules passes to the stems, leaves and fruit.  I doubt very much whether just 3% of the original fix of nitrogen remains in the roots because I have read that up to 40% does.  However, I'll go with the 3% because it is not relevant. 

Dowding says that to get an increase in soil nitrogen you have to dig in the stems when they are in full leaf.  Well yes.  Even though I was keeping a lot of fruit for seed, I still dug in the beans when they were in full leaf.  They were in full leaf until almost the end of November.  Even when they are caught by the frost, the leaves and stems and consequently the nitrogen are still there and can be dug in blackened.  I don't see the problem.  Nitrogen does not flaunt the law of conservation of matter.  It does not disappear.  If all the leaves fall from the stems onto the soil surface they will add their nitrogen to the soil eventually.  Even if you leave the plants till the end of the winter and they are brown and crinkly, they will still contain some fixed nitrogen and can contribute to adding extra nitrogen to the soil. 

The problem for others is that the root or the root nodules are seen as the only source of nitrogen that beans plants contribute.  I hope to explain why this is a misconception. 

I questioned this on one website and they said that they were trying to simplify nitrogen fixation for general gardeners.  If we are going to try to overcome misconceptions then we have to tell people exactly what is happening based on evidence and data.  And anyway who decides whether something is difficult or easy?  Is there a scale of difficultness. If so what are the units?

All these bean plants have been dug into the
soil to add a small amount of fixed nitrogen.
-everything helps
I have also seen the misconception that all of the nitrogen produced by nitrogen fixing bacteria passes into the seeds of legumes.  This would wrongly suggest that digging in the roots and stems of say runner beans would not necessarily introduce nitrogen into the soil. 

It is true that a lot of nitrogen passes into bean seeds (and this is where vegetarians get some of  their protein from.)  Indeed all plants pass nitrogen, as part of protein, into their seeds.  (That's why vegetarians eat lots of nuts. ) 

Why am I talking about proteins rather than nitrogen?  The element nitrogen is incorporated as part of protein molecules almost immediately it has been fixed by nodule bacteria like Rhizobium leguminosarum  or Rhizobium gallicum and passes into the plantThese proteins are then used throughout the plant for a vast number of different jobs.  So to say that all or even most fixed nitrogen is passed to the seeds or stays in the root nodules seems hard to believe.  Even if only a small amount of nitrogen is left as protein in the main structure of the plant, you are still getting an increase of nitrogen that can be incorporated into the soil if you dig in the bean plants at the end of the season. 

If you cut the tops off beans and burn them then the nitrogen will be lost to the atmosphere as nitrogen oxide gases.  At the very least the tops of beans and peas should be composted for their fixed nitrogen. 

However, why not just dig the whole plant in? 

Tall climbing pea plants have been dug into the
soil to add nitrogen.
Some books say just dig in the roots.  The roots contain Rhizobium filled nodules.  The usefulness of nitrogen, as a basic building block of proteins, would mean that it would be transported away from the nodules as quickly as possible.  Thus there would be no more nitrogen in the nodules than there would be in the rest of the plant.  The increase in fixed nitrogen is distributed as protein throughout the plant.  The farmer does not mow off the leaves of clover and just plough in the roots.

Everything helps, so dig in the whole legume plant.  Why wouldn't you?  Maybe because the stems are a little woody and this might lead to nitrogen immobilisation?  Possibly, but the jury is definitely out about how much woody chippings cause immobilisation so a few bean tops, which in my anecdotal experience rot down relatively quickly, are not going to cause a problem.  Also  legume green manures, such as vetch, tare, fenugreek and field bean, are dug into the soil, tops and all. So why not beans and peas? 

Green manure of tares, clover and rye grass

Once the legume plant dies, the Rhizobium bacteria pass back into the soil where they can survive but do not fix nitrogen.  The nitrogen contribution that  bean roots make comes from decomposition of the proteins that make them up. 

Sweet peas were used as a break crop and
 dug in as a legume nitrogen fixer.

There are other free living nitrogen fixing bacteria but they are not thought to make a very significant contribution to total soil nitrogen.

A misconception I had was that legumes could only introduce nitrogen into the soil when they were dug in.  However, as with other plants, the turnover of their roots is quite significant.  They are loosing material from their root tips continually and root hairs only have a very short life.  This is why lawns with clover growing in them look much healthier and a darker green than those that don't. Indeed, Abercrombe suggests that during the eighteenth century the lawns of the super rich Victorians were sown with a grass clover mix. 

The nitrogen is coming from the death and decomposition of proteins in roots, root exudates and sheared off cells.  Not necessarily from root nodules which only contain bacteria.  The only way that root nodules would contribute to soil nitrogen is if they were seared off or died and the protein within them decomposed.  They are not little bags of nitrogen as Dowding seems to suggest. 

Dowding's objection to green manures really stems from the fact that most gardeners will dig them in and he doesn't like digging.  Well actually you don't necessarily need to dig them in or compost the tops as he suggests.  If you lay cardboard and chippings over them,  maybe tarpaulins or black plastic or even as a last resort carpets, green manure will decompose under the soil covers but above the soil.  The soil does not have to be disturbed and you get the benefits of the nitrogen fixation and added organic matter. 

So this is why I have planted legumes  Laburnum anagyroides and Lupinus x Russel Hybrids at the top of the allotment slope.  I am hoping that any fixed nitrogen that is produced by the decomposition of root proteins will be taken by mass flow of water through the allotment soil thus making it available for the vegetables down slope. 

Which takes us to another misconception: the danger of  Laburnum spp..  They are not that poisonous and are no more poisonous than sweet peas, cherry laurel, pyracantha, and even French beans ( Phaseolus vulgaris).    A hysteria about laburnum in the UK means that they have been rooted out of all UK school gardens.  Have a look at the Youtube film:

I grow  laburnum, sweet pea and lupin on the allotment as nitrogen fixers.  I just don't eat them.

Thursday, 3 December 2015

Myths and Legends; Misconceptions in Gardening.

It's all a conspiracy - the world is flat.

I've just bought Charles Dowding's book; "Gardening Myth and misconceptions." published in 2014.  I have read its 91 pages fairly quickly and found it really interesting. 

He, like many other modern commentators, are following an long tradition of challenging gardening misconceptions. 

Ralph Austen's in his 1653 book; "A Treatise of Fruit Trees Showing the Manner of Grafting, Setting, Pruning and Ordering Them"  set out to expose myths during Oliver Cromwell's time. 

He rejected the idea: "To have all stone fruit taste as you shall think good, lay the stones to soak in such liquor as yea should have them taste of."  Together with: "To have red apples put grafts in pike's blood."

Both perfectly reasonable assertions.  (My choice would be Scotch whiskey.)

As are modern misconceptions - put science misconceptions into Utube and you will be very surprised about what ordinary people think about science "facts" that have relatively large amounts of evidence to suggest that they are more or less correct. 

Evolution is rejected even though it is the explanation of hybridisation (Fairchild's mule), plant breeding, plant cloning(taking cuttings), the origin of flowering plants, plant adaptations and interactions with pollinators, plant genetics and grafting.  (Why you can't graft a peach onto an apple. Has God done this just to be awkward?)

Lettuce, believe it or not, does contain protein!  All living things that we know about have proteins.  Proteins are fundamental to life on the Earth.  Don't ask me as a vegetarian where I get my protein from!  I get it from lettuce.   

Let's remember photosynthesis when considering where the mass of a tree comes from.  Yes, those  
Sequoiadendron giganteum are overwhelmingly  just wisps of carbon dioxide gas and drops of water and so are we.  The scraps of other nutrients that plants get from the soil are minisculely insignificant in comparison.  They do not get their mass from the soil.
"General Sherman tree looking up" by Jim Bahn - Sherman Tree
Uploaded by hike395.
 Licensed under CC BY 2.0 via Commons -
That's why General Sherman does not have a gigantic hole around it.  I  know cus I've been there.
I must admit to a vested interest in science misconceptions.  They were my area of research while I was teaching at University and my Master's degree was in the public understanding of science and science communication.  I was researching the misconceptions of children and found that my students - some of which were Masters graduates - seemed to have the same misunderstandings. 

One of the areas I interested in was people's understanding of the phases of the Moon.  This is how we see "daylight" and "night" on the Moon's surface from earth (the planets including the Earth have phases too!).  I have to be careful here because a day is defined as 24 hours on the Earth.   Many people still think that phases of the Moon are bought about by the shadow of the Earth and some children think you can sit on the crescent Moon fishing.  Dowding, although cautious,  seems to suggest a connection between how we see daylight and night on the Moon and the most auspicious time to plant seeds.

Most scientists would say that correlation does not mean cause and effect.  Something that social scientists really need to take on board.  Particularly those in education research.  If its not significant - then it is not significant.  A great deal of evidence is needed to establish  relationships.  As Robert Pavlis  says on his blog, "Garden Myths".  If it is anecdotal then it is anecdotal - not scientific evidence. 

A major misconception - particularly with scientists is that they are dealing with "facts" rather than reasonable consensus based on current evidence.   At the moment we rely on statistics and significance to indicate relationships although how robust this is, can and should be questioned. 

Social scientists in the 1970s and 1980s started to question whether science was as objective as it made out.  It would seem that a great deal of science seemed to have been noticeably distorted by cultural considerations.  This was not done deliberately but as a result of science being embedded in culture. 

You can see this particularly in gardening myths.  What seems to be a "religious" approach to modern compost making probably originated from the Victorian kitchen gardens of the super rich.  There were no scientifically developed seed and cutting composts so they had to develop these composts for themselves.  Each head gardener would have their own recipe and methods.  However, nowadays we can buy reliable growing media from a garden centre without having to go through what seems to be a religious ceremony to produce the same thing from garden waste.  You don't need anything or to do anything special to produce very passable compost.  Just heap it in a pile and leave it for a year.  Now if this is not questioned then it will carry on as it has for 300 years. 

For example the term, "well rotted manure or well rotted compost" is used by Abercrombe's  in the 18th century through Loudon in the 19th century until the television programs of the 21st century.  No one seems to question what "well rotted" means.  However, Dowding does say use year old, friable manure.  I just wonder if it is a year from when it comes out of the animal or one year from when it was delivered to the garden - or whatever.  What is well rotted manure?  I am not really bothered because I put it on the garden as soon as I get it anyway.  Its not doing any good in a pile. 

Which takes us to the "burning of roots" misconception.  While fresh stable manure quickly heats up in a four or five foot pile,  it doesn't do this in a thin layer on the garden - anecdotally.  However, if the manure is nutrient rich then there may be an increase in the concentration of salts in the soil and water will tend to be drawn out of the root giving the impression of "burning. "  But I have never seen this in all the years I have been heavily manuring the allotment.  Thankfully Dowding seems to agree with this.  The Victorian kitchen gardeners used fresh stable manure packed into 3-4 foot stacks to make hot beds and this might have been where this came from.  Also they had so much manure compared to today that they could leave it to rot down for some time before using it. 

Dowding says a little bit about nitrogen depletion by woody material as well.  The Victorian gardeners did use bark chippings called tan, produced from the tanning industry, to make hot beds.  However, they did not use it on the soil probably because they did not need to.  They had so much manure.  Digging in branches and woody stems would have seemed perverse to the outdoor gardeners because it would make digging that much more difficult.  To keep digging up long woody stems would slow the work down and make it hard. 

There is little solid evidence that woody chippings necessarily produce temporary nitrogen depletion particularly if used as a mulch.  I can't be sure where this misconception has come from but it sure is tenacious. 

One of the findings about misconceptions is how difficult it is  to change them. The attitude; "it doesn't matter whether you are right or wrong, what matters is whether you are sure." can be adopted by the religious and conspiracists but should not be the mantra of  the scientist. 

What irritates me a little is the way people use science to debunk science.  You can't logically do that.  You need to question the evidence.  Dowding does the, " Aha got you."

This is because they do not understand the nature of scientific method.  If older data suggests that there is a lull in global warming then a more recent set of data suggests that this is incorrect, it does not invalidate science.  This is just normal science - as technology improves the resolution of the data also gets better.  Questioning  other people's data is a fundamental process in science.  Scientists are doing it all the time.  They will be very dismissive of other scientists research and challenge them at every turn.  I know because I have been at the receiving end of quite severe dismissive criticism.  However, I would not have it any other way.  I would rather have the criticism than publish research that was not correct. 

This does not mean that science is incorrect just that people are being as rigorous as they can be.  Science research can be a rough and tumble world especially if you are working in a controversial area. However, scientists have powerful methods and big machines that test out theories so if anyone is likely to discover inconsistencies - believe me they will.    A lot of scientists would like to debunk orthodox theories but they need to come up with very secure data to do so.  You have to be right not just sure. 

So the word "proof" and the word "truth"  should not really be applied to science.  I would rather use the word "probably" and, "the weight of evidence suggests at the moment. "  But then I am more of a social scientist than a proper one. 

Thursday, 26 November 2015

Moving the lavender.

I dug over the strip of soil along the new onion bed beside the path.  This was just to turn in the green manure that was growing there.  I took out the lavender plants and planted them right up to the curbing along the path adding some mychorrhizal fungi to the planting holes. 

Green manure before I dug it in. I didn't dig any
manure in keeping it for the onions. 

I started to clip the plants with a pair of secateurs but I was not achieving the effect I wanted so I got out the garden shears.  I got a much straighter edge along the top and both sides with the shears.  I cut the plants back to about 5 inches high and 5 inches across.  It has made a very tidy edging to the bed.  I  don't think that they used lavender as an edging plant in the Victorian kitchen gardens but I may be wrong. 

There was enough room at the end of the row to put some more plants in alongside the path.  Two  rosemary plants were being overshadowed by the big Victoria rhubarb plants so the rosemary plants were taken out and added to the end of the lavender row.  They were clipped to the same size as the lavender.

I also went up and clipped the rosemary by the small greenhouse to about the same size.  It is a little more scraggy than lavender and does not make as good edging plant, however I am growing the rosemary as a herb rather than an edging shrub. 

Rather than throw all of the clippings onto the compost heap, I put some of them into the cold frame as cuttings.  I have just planted them in the cold frame soil rather than in pots because I am not too worried if they do not take. If they do root, I will put them as an edging along the path on the far side of the allotment. 

Although it was quite wet, the path was swept; picking up the soil that had fallen from the beds and leaves that had fallen from the hawthorn hedge.

I am going to plant one of the apple espaliers behind the lavender; probably "King of the Pippins".  With that in mind, I painted the tree posts with the Cuprinol I had left over from doing the sheds.  I doubt very much if the paint will make the posts last any longer than if they went without, especially as the posts are tanninised.   However, it does make them look better and blend into the allotment a little more than if they weren't painted. 

Also, if I don't use it on the posts, I have no other use for it and it will fester, taking up space in the shed, until I decide to take it down to the tip.  So, I am trying to use it up, so that I can take the empty tin, with the rest of the tip stuff, to the waste disposal site. 

I still have to get stretchers to put at the top of the posts to stop them leaning in when I string the wire across and pull it tight. 

One of the scaffold nets had been put over the green manure on the old brassica bed and the green manure was starting to grow through it.  If the green manure plants get too big then they get stuck in the net and are pulled out when the net is taken off. So, I took the net off today and put it over the white grape.  This will protect the grape a little and also enable the rain to wash off the soil from around the edge of the net.  I have just draped it over for the moment but I will have to tie it in with some wire before the next storms come.

As I am following Geoff Lawton's method of composting, the compost has to be turned every two days.  It was raining yesterday so the compost was not turned so I did it today.    I turned seven of the eight bins before it got too dark to carry on. 

Six of the compost bins.  I added two more
last week.
So, why am I turning the compost? 

I'm not really sure.  Looking at various books they all recommend turning compost but don't really explain why it is worthwhile to do. 

The first explanation is that the cooler parts on the outside of the compost can be turned into the middle and start to heat up.  Heating up the compost can destroy weed seeds and diseases, however I don't think that my composts heat up nearly as hot as necessary to achieve this. 

They do heat up though, although now it is getting into winter they heat up even less than they did during the summer. 

The second reason they give for turning the compost is that it introduces oxygen into the heap and allows aerobic decomposition.  Turning certainly keeps the compost open and friable with large air spaces.  This obviously encourages the worms to enter the compost and to reproduce.  There are certainly a lot of worms in the bins. 

I think that turning also helps to distribute water through the heap and eliminate dry spots.  It is easy to add a little comfrey water to the bin as it is being turned, if the compost is too dry. 

Turning certainly seems to speed up the decomposition process and produce reasonable compost in about a month.  However, if I was to look at a normal, unturned  heap after a month, could I still sieve out some good well rotted compost?  Probably so. 

So I turn to the final reason why the compost the compost should be turned.  It provides some good exercise for the person doing it.  It is relatively easy using the composting bins because they can be taken off and moved a little before they are refilled.  Also the compost is relatively light compared with topsoil.  However, it makes my muscles ache a little doing it every two days. 

In the Victorian kitchen garden, compost was carefully made because it was used as potting and seed compost.  It was important that weeds and diseases were destroyed by the heat of the heap.  Nowadays we can buy sterile "seed compost" and "potting compost" from the garden centre and we don't need to be quite so particular about how our own compost is made. 

It is interesting to note that turning the compost, which I would say is very similar to digging in the garden, seems to increase the number of worms.  Furthermore, as the increased rate of decomposition demonstrates, there must be a rise in the population of microorganisms and fungi.  Why are we warned that digging will destroy soil organisms when it obviously doesn't in a compost heap or bin?

I would suggest that there is  a similar increase in microorganisms in the soil, after turning over during digging, decomposing organic matter that was previously chemically or physically protected from decay.  There are several studies that suggest that there is a rise in the volume of carbon dioxide given off after digging and this also indicates a rise in the number of microorganisms decomposing organic matter.  There is also evidence that digging reduces the amount of organic matter in the soil. 

So I would suggest that digging does not destroy soil organisms rather the contrary.  However, digging does reduce the level of organic matter and this is a very serious matter.  Organic matter does many things in the soil and its loss will tend to reduce the fertility of the soil.  This is why lots of organic matter should be added throughout the soil profile if you decide to dig.