Out of control allotments (2)

 

If you think that I am going to give you a list of quick ways of controlling a weedy allotment then this is not for you.  Turning an allotment around, whether it is new or has been allowed to get overgrown, is not an easy project.  It will take time and commitment.  There are some fairly quick ways that will take a year at the most.  

•         Double dig with skimming.  This is where you divide the plot into two parallel areas.  Skim off, about a turf thickness of weeds, from one area and leave in a pile. Take out a trench one spade width wide where you have skimmed off the weeds and leave the top soil and first spit of subsoil on the other area.  Take the next trench top soil out and leave this on the pile in the other area too.  This will give you steps. In  the first (yellow) trench fork the bottom so that you go down another possibly 30cm.  

 

• Place upturned weed turfs along the bottom of the first trench (yellow) and cover with the next trench’s subsoil (light brown).   Complete this trench by putting the next trench’s top soil on top (brown).  Now you have got steps again.  Fork the bottom of the deepest trench, skim off some more weed turfs and put them at the bottom of the trench and cover with subsoil.  Add manure or compost if you have any and the next trench’s topsoil goes on top of this.  Continue until you reach the side of the area then go over to the adjacent area to get top soil and subsoil to fill the trenches.  You will dig trenches on the new area so that you can work backwards towards the piles of soil you took out of the first trenches. 
• Try and get as many of the perennials, such as couch grass and dock, out of the skimmed soil so they do not regrow.  I reckon that they will come back no matter how diligent you are at removing stolons and tap roots so be prepared to have to weed out regrowth after  a couple of months.  If you carefully cover the skimmed off weed turfs with subsoil then with top soil, there is very little regrowth because they are buried so deep.  Persistent perennials do not like to be disturbed so if you continue to dig and fork the ground removing the roots, they will eventually die away.  It will be time consuming and hard but if you want a good allotment you have to do it so get over it.

The 2nd February 1982.  My allotment when I was skim and double digging it.

• Digging is the best way to clear the ground, put air into compacted soils, help with drainage and introduce some organic matter to produce some nutrients.   It’s not easy and it is hard work.  It is one of the most effective ways of getting an allotment into producing good vegetables relatively quickly. 

•  Cover the ground with thick black plastic; the second method.  This prevents light from reaching the plants and they are effectively starved to death.  Several drawbacks include; it’s an expensive method unless you can cadge, scrounge or beg some; the plastic must be weighted down effectively so it does not blow about and fall on my allotment; storing it when it is not in use (you will need big pieces that will blow about onto my allotment if it's not very carefully folded up and put into a shed where it cannot do any damage to other peoples’ allotments); and finally it seems to attract hundreds of slugs and snails that seem to migrate onto my allotment and end up eating my vegetables rather than yours.  Some people use little pieces of plastic, cardboard, newspaper and carpets.  They soon find that plants will grow around the edges, through holes and anywhere light reaches the ground.  And finally, I have not found anything more effective than carpets to attract rats onto the allotment.  You might be thinking that I am not too keen on this method, however I am using some tarpaulin at this very moment for the very first time.  Needless to say, it is weighed down by the parts of an old concrete sundial, several concrete slabs and some full plant pots SO IT DOES NOT BLOW ONTO ANYONE ELSES ALLOTMENT. 

• The third way involves chemicals and you have got to ask yourself why you are growing your own vegetables.  If it to grow organically, so you can give your family vegetables that are not contaminated, then you have to avoid this method of clearing an allotment.  If it is not, I am not going to encourage you by telling what chemicals to use or how to use them.  Sort it out for yourself.   

My Rant About Garden Bonfires

This is one of my rants on bonfires.  It is quite amusing to think of how my thinking has changed lately because of the debate around Terra preta and the role of charcoal in improving fertility.  I will make the compromise that charcoal production and application to the soil is probably a good idea.

Now I may be a grumpy old man but I do find the need to light bonfires at the slightest excuse really irritating. Gardens do not need fires. They are the antithesis of gardening.

The whole point of gardening is to get out into the fresh air, give yourself exercise and grow some good wholesome vegetables. Or that is what I thought but what do I know. Autumn and winter seems to be the season of fire lighting.

Garden fires produce carcinogens - cancer producing substances. You lose the nutrients locked up inside the plants when they burn. 90% of nutrients are lost to the air through the production of gases such as nitrous oxide, sulphur dioxide and the particles in smoke. It adds carbon dioxide to the atmosphere unnecessarily . You do not get rid of stuff. It is still there - just changed- and some of it dumped onto surrounding allotments.

What do you do with diseased plants? Well one thing I would not do is heap them into a smelly, smoke ridden pile of rank plant material because I will guarantee that you will not destroy pests or diseases in that way. Heat is one of the ways of killing microorganisms, however I would be surprised if the heat generated and the architecture of a normal smoky garden fire would be a reliable way of safely disposing of diseased material.

If you walk away from a fire and leave it unattended surely you are an arsonist? If you say that you cannot put the fire out then it is a fire out of control; so should the fire brigade be called?

There are alternatives to having fires. You could use your green bin if your local council provides one, you could take it to the tip or you could bury it on the allotment. I have never met a problem that shredding, burying or composting did not solve. Burning is not the answer.

I have experimented for several years now burying large logs and tree branches when double and tripple digging. The accepted wisdom is that this practice will remove nitrogen from the soil. Bacteria and fungi rotting the logs need nitrogen and they absorb it from the surrounding soil. 

Now this may be the case, however, if the logs are buried below the normal root run of vegetables any nitrogen that the microorganisms remove would not be available to most vegetables anyway. I am talking here about burying at least two spits down in subsoil. Nitrogen is usually leached from the soil and this may be a good way of trapping this nitrogen and giving us the potential of recycling it into the top soil when the logs have eventually rotted away. In my experience the rotting process is relatively quick and the soil formed is very friable. In any case, what goes around comes around and the nitrogen that has been locked up by bacteria decomposing the wood will be released eventually when these organisms die and this can then be recycled into the soil when the bed is double dug again. 

I call this the Montezuma method. These South American Indians knew what they were doing. They were excellent horticulturalists and agriculturalists. They built vast floating gardens that fed cities. They floated gardens on logs and brush wood. They used brushwood when making their terraced farmland.  Regardless, it does not seem to have any adverse effect on my vegetables.

I am using shredded lalandii on top of brushwood (small branches)

I used quite a lot of lalandii and it did raise the allotment a little too much.

The subsoil went on top of the lalandii shreddings.

Leaves were then added...

Finally the topsoil was put back and a new trench was dug.

Earlier last year I buried a leylandii tree two spits down by double digging and burying it under the subsoil. I have just dug down to see what has happened to it and I cannot find any trace of it.

Burying logs has several advantages. It raises the soil above the surrounding area. As there are two springs on my allotment, raising the soil level means that the water flows below the soil and into the subsoil. The surface 6 to 8 inches are normally well drained. The logs and brush wood seem to leave drainage spaces in the soil which water can flow through easily.
I am burying carbon that would otherwise be converted into carbon dioxide and add to the carbon load of the atmosphere. While carbon dioxide and methane are produced from the rotting process, I would suggest that most of the carbon will be left in the soil. There is evidence that soil could be a carbon sink and buried carbon in the form of logs and brushwood could stay in the soil for hundred or even thousands of years..

What are the environmental and human health impacts of burning massive piles of stuff especially  stuff that isn't normally meant to be burned?
Open burning of any kind is generally bad for us and particularly nearby allotments like mine. Compared to controlled burning, such as in boilers, large outdoor fires tend to produce highly mutagenic and carcinogenic emissions that can affect anyone digging in the next allotments.   (Mutagenic chemicals,  are those that  cause genetic mutations.) The  fine particles in smoke can get into eyes and lungs and cause bronchitis, as well as aggravate existing conditions like heart and lung disease.

Smoke from any bonfire, including  ones built with wood or paper, add particles and carbon to the atmosphere,  These can act not only as air pollutants and can contribute to climate change. Particulate pollution can lead to lung and nose irritation, and lung cancer if exposure is severe and prolonged.
Ash from bonfires can also easily run off into streams, rivers and lakes, introducing chemicals and possibly altering the pH of the watershed.

Burning most kinds of plastics or metals is a quick path to creating a significant hazard for those near-by, or even farther afield if there’s wind. The potential for adverse health effects goes up because these are inherently toxic and the gases that are produced in the chemical reaction of the fire are equally as dangerous, if not more so. 
Some of the worst items to burn in terms of toxic emissions include manmade chemicals like Teflon or  other plastics, used motor oil and rubber such as that found in tires all of which I have seen on allotment bonfires.

There are no safe bonfires.

Sorry but I am going to get you on global warming...

Since the drought of 1976 I have been thinking that there is something happening to the weather. Before 1976 you never got roses after October. Afterwards, until this year, I have had flowers on my roses right up to December.
Before 1976 I found growing cucumber, tomato and sweet corn outside very difficult without a lot of care and protection. Now they are normal outdoor crops that I grow every year. I can grow busy lizzy outside and leave dahlia tubers and gladioli in the ground overwinter! I never did that before 1976.
Whether you think that it is Sun spots or human greenhouse gas does not matter. The climate is changing. It does not matter whether you believe it or not. It is not a matter of belief – it is a matter of interpretation of data. The weight of evidence suggests that global temperatures are increasing. While scientists debate whether human activity causes it or is just augmenting it, the vast majority read the data and interpret it as a climate changing event.
It is the same science that makes your mobile telephone work, your fridge to keep your food cold, the engine in your car work, explains how seeds germinate, what fire is, what smoke is made up of and what pollution does to our environment. If you reject one part of science you reject all science.
Don’t “believe” in global warming, don’t believe that man reached the moon in 1969, don’t believe that evolution is a fundamental process of biological science and don’t believe that cigarettes cause cancer. It does not matter. That does not change the data, the measurements or their most reasonable interpretation.
If you want to believe something, believe that all souls weigh the same.

I am going to believe that I will be able to grow carrots without any root fly damage this year. 

There were changes in the climate and there has been since the Earth formed. Ice ages are a good example. They were probably caused by fluctuations in greenhouse gases and radiation from the Sun. Just like today.
Science does not prove things one way or the other. Scientists leave proof to mathematicians. Science does not deal in facts although lots of scientists would argue with that. Good scientists go with the data, their measurements and try to interpret them as reasonably as possible.

Let me give you an example. I could grow a row of peas measure their height and the weight of peas I got from them. I could measure the amount of nutrient added to the soil. I could relate that to the weight of peas obtained. Yet you could come along and say you don't believe in my peas and you are not going to look at the measurements because the peas do not exist. Your belief does not alter the existence of the peas one way or the other. The problem comes when your belief makes you walk across my allotment as if the peas were not there and destroy them all.
Science does not prove things; it just interprets data, hopefully reasonably. 

Totally agree bad data produces bad interpretation. Any scientist worth their salt would have questioned, and did question, the Himalaya assertions. I don't think that they based their report on any scientific data whatsoever. They just believed it to be so.
But it was basic physics that enabled us to question those assertions. Questioning data is a fundamental part of science and is going on all the time not just with silly assertions about Himalayan glaciers. That's what they were doing in the leaked emails. They were talking about how they were going to challenge someone's data. Very legitimate part of science.
How could you do it any other way without waiting until 2030? You cannot use science to shoot science down.
Fiddling the facts is not part of science. It may be part of corporate business, government spin, and people's financial gain. Again, though just because they are doing this does not change the data. The measurements are the measurements. People are wrong to fiddle data and there are a lot of scientists out there that are much cleverer than I am that will shout their objections very loudly; just as they did with cold fusion. To say that things are not happening because you believe a tabloid newspaper or Jeremy Clarkson does not alter the data either. The truth will out…
The most reasonable interpretation of the data is that the climate is warming. Don’t take my word for it just look at the graphs on http://www.realclimate.org/ for yourself. I would wish a lot more people looked at the data for themselves rather than rely on a television presenter for their views. There is also increasing evidence that human activity has caused this temperature increase. There is further evidence that this increase in global temperatures is affecting low lying ocean islands due to rise in sea levels. Expansion of the Sahara desert in Africa is a lot more serious than whether you have to pay more tax for your lawn mower petrol.
This is just the beginning. 

As Jesus said: there is none so blind as those that cannot see. 

I agree that the weather is fairly cold at the moment, although nothing like I remember in the 1950s and 1960s. That has little to do with global warming. The southern hemisphere has had one of the hottest years since records began. That is to do with climate not weather.

Comfrey, Nettle and Sweet Cicely Tea

I have five rows of comfrey and two rows of nettles grown properly with weeding and hoeing.  I am also using sweet cicely which also makes a good liquid fertilizer.  I harvest them by cutting near to the base of the plant and take off all the leaves.  They are then put into one of two very large butts I have.  I do not add any water, although I have made comfrey tea using water in the past.   I leave the comfrey, nettles and sweet cicely leaves in the butt for about a month or two.  However, I keep draining off the tea using taps at the bottom of the butts and putting into the dustbins with charcoal. 

The tea looks just like Tomorite to me.  I keep filling my butt up with leaves throughout the year as they rot down. I try not let the plants get too big or flower. I harvest the leaves about 5 times a year putting the leaves in the same butt unless it is full. I have other butts that I can put comfrey in if I have too much. There is a tap at the bottom of the comfrey butt and I use this to put some in the watering can each time I water things. It is relatively high in potash (K) - good for flowers and fruit. So, yes you can keep adding leaves to the butt if you want to.

They say that nettles are high in nitrogen and comfrey is high in potassium. Compared with what though? I think we are talking about very small amounts of nutrient but that is all that most vegetables seem to need. Nettle and Comfrey have more nutrient than farmyard manure but farmyard manure has very little nutrient in, so it does not need much more to be better. 

Ken Thompson in his book "An Ear to the Ground"  says that Russian Comfrey Symphytum x uplandicum  is rich in all three main mineral nutrients, nitrogen, phosphorus and potassium but it is not unique in this.  "Some plants can do just as well, maybe even a little better  including: chickweed (Stellaria media),  nettle  (Urtica dioica), sweet cicely (Myrrhis ororata), fat hen  (Chenopodium album), goose grass (Galium aparine), and hedge garlic (Alliaria petiolata).  So I chuck some of these into the butts as well. 

I think that the adding of both comfrey liquid and farmyard manure have greater effects than just adding nutrient to the soil. They encourage soil organisms which may form symbiotic associations with plant roots or at least provide further nutrients or nutrients in a form that the plants can use.

Healthy soils with lots of dead plant matter, humus and microorganisms grow good plants.

Comfrey is as tough as old boots. It will certainly come back in the spring. Mine has died completely back and is difficult to make out at the moment. I tried digging between the rows and started to dig up roots. Not to worry though because I just planted them again. They might not come but I have sufficient anyway.

A bit of frost and snow will not hurt comfrey.

Carrot root fly

Carrot root fly Psila rosae is one of the most irritating pests on the allotment.
There is a photograph of it here:
http://photos.eppo.org/index.php/image/2638-psilro-04

I think that it is safe to say that adults are flying and laying eggs from May to November.  The only time that there are no flies is from November to April.  There are two peak times when the flies are flying and this suggests that there are usually two generations during the summer.   The first generation is from the end of April to the end of May and the eggs are laid from the end of May to the beginning of July.  The second generation begins hatching from the beginning of July to the middle of August.  Most eggs are laid from the beginning of July to the beginning of August. A third generation hatches from late September to late October and the larva from these overwinter in carrot roots and other wild members of the carrot family.  Most wild species are less prone to carrot fly than the average cultivated carrot and sustain less carrot flies per plant.  Fools parsley Aethusa cynapium is an important host so it is worth getting rid of it if you have it on or near the allotment.  They can lay eggs until the middle of November so either the carrots have to be lifted or kept covered with enviromesh even at this late date.  This third generation starts to cause damage as the weather becomes warmer in the spring and can lead to very high fly populations the following April. Really, any carrots still in the ground must be dug up before the end of March to avoid the larva from hatching out. 

  

Trying to avoid planting at high concentration times seems to be impractical for the amateur gardener.  We need to plant when we are able rather than at the most appropriate time.  So it seems that the most effective way of preventing flies from laying eggs around carrots is to have a physical barrier such as fleece or my favorite enviromesh.  Evidence suggests that carrot root flies are weak fliers; not flying  particularly high.  Putting a barrier about 60 cm tall around the carrots, they suggest, will prevent   Psila rosae from reaching your carrots.  Not in my experience.  The research shows that there is only 15% drop in damage within fences. I would suggest the little beggars get over fences easily.  Other people have suggested growing in pots lifted up on some kind of support.  Tried this and putting carrots in a big blue barrel full of sifted soil.  Still got carrot root fly.  

The only way I have prevented carrot root fly and got reasonable carrots is by completely covering them with enviromesh.  I put in wire hoops  and then cover with the enviromesh.  When I put on the enviromesh I bury the edges and ends in the soil to form a really good seal.  However, there are drawbacks with the method; it is expensive, and conditions under the netting encourage the development of fungal pathogens and weeds, which is why I thin and weed under the mesh.  

I am also going to experiment with cloches next year.  I don't think that carrots like the heat generated by cloches though so it may not be as successful as I would like. 

Carrot root flies are most active in the late afternoon or early evening.  They are crepuscular.  There is a distinct crepuscular peak particularly in the evening. I emphasize this because I have seen the morning suggested on various web sites.   So if you are weeding or thinning then it may be best to do this before the afternoon.  However, I have done these jobs in the afternoon and if you get the enviromesh back on the carrots fairly quickly then the flies do not have time to lay eggs.  As this suggests, I take off the enviromesh along one edge to weed and thin. 

There is some evidence that carrot root flies use the scent of the carrots to hone in on them.  This has led to experts to suggest that you do not thin carrots.  Just sow the seeds thinly.  I do not agree. If you want reasonable sized carrots then you need to weed and thin them and this is what I do.  It probably does bruise the carrot foliage and produce more attractants but believe me the little beggars are going to find your carrots in any case, whatever you do unless you protect them.  There are many different theories about how the flies identify their food plant and foliage shape is another one.  

I use the fly resistant varieties such as Flyaway.  These varieties have been bred from Vertou, Nandor and Sytan but amateur gardeners do not seem to be able to get these varieties. Researchers do not seem to know exactly why these varieties are resistant but Flyaway seems to work well under my enviromesh. 

Intercropping with the clover family helps to prevent infection but undersowing produces too higher level of competition between carrots and companion plant, which lowers the yield and produces split carrots.


Intercropping with one or more rows of onions planted between each row of carrots has led to a modest decrease in carrot fly damage, the strength of which depended on the ratio of carrots to onions. The best effect was achieved when four rows of onions were planted between each row of carrot.  This is fine until you get the onion miner fly too as I have.  Also, if you are trying to keep to a ridgid rotation of crops, onions do not really go with roots. 

What you are trying to do here is put a crop, carrots, that do not need a lot of manure with onions that do like manure. I still question whether carrots fork and split if you use manure with them but maybe you can circumvent all of this by applying compost to the bed. That should satisfy both of them. 

I tried marigolds and chamomile around both the onions and the carrots but I could not see a noticeable effect in pest prevention.

That might just be me and my conditions though. Brightens up the allotment, though.

Rotating carrots each year is another way of reducing carrot root fly damage.  The distance that the amateur allotment holder can move the carrot bed is limited so this may not be as effective for gardeners as it is to farmers.  The fact that there is more damage to carrots growing near to hedges and ditches shows that planting as far away from them as possible may reduce damage.  It is a shame that my allotment is so close to the hedge. 


I have grown a great many different varieties over the years, however carrot root fly seems to have become worse over the last ten.
After resisting for several years, I eventually had to grow flyaway.
I was pleasantly surprised by the taste. We used it both in salads and steamed.
It just shows you how much better fresh vegetables taste, regardless of the variety.
If you do not have too much carrot root fly you have to go for Nants - it is a special taste, and for autumn and winter with big roots I would have to go for Autumn King too.

I have been growing Flyaway for several years now but I also cover the carrots completely with enviromesh using piping to keep the enviromesh off the plants. I have tried planting Flyaway with no protection and they do get damaged by carrot root fly.
I gave the carrots a couple of ounces of blood fish and bone when I planted the seeds and have got some really good roots this year. I think that thinning out is possibly a way of preventing too much damage by the carrot root fly. I thinned out to about 8 inches apart. It is a bit of a chore to keep removing the enviromesh to weed and thin but it was worth it to get some decent roots. I left them in the ground so I hope the frost has not done too much damage.

Mulching with lawn mowings or bark chippings did not have much or any effect on carrot root fly damage.  There is no connection between the amount of carrot damage and the number of carrot fly predators. 

Companion planting with lucerne and clover does reduce the yield of carrots due to competition.  However, the effect of companion planting on the reduction of carrot fly damage compensates to some extent for the suppressed yield due to companion planting.  There is evidence that carrot root flies have more difficulty in finding carrots to infect when companion planting is used. 

If leguminous plants are used as a companion plant, i.e. low growing clovers, tares, vetches etc. there is an additional bonus of fixing atmospheric nitrogen. 

Digging in the tops of these legumes will give about 60 grams of nitrogen per 100m²  digging in the roots will give 10 grams of nitrogen per  100m² . 

This is important Tone.  You seem to get more nitrogen from the tops of legumes than the roots.  So make sure you always dig in the tops of peas and beans too.  Do not burn them. 

So that is how I grow my carrots. 

Out of control allotments

Are we to say that those that do not or cannot do their allotment should be asked to relinquish it? My gut reaction is to say yes. Unkempt allotments are unsightly and detract from the quality of the whole allotment site. Weeds spread across the allotment; there is a home for allotment unfriendly wildlife, getting past them with the wheel barrow is a chore, they can attract human vermin that see the allotments as somewhere no one cares about and they become dumping grounds for other people’s rubbish.

I have very little to do with the allotment committee. This is not a boast but out of necessity. Working full time means that all free time is devoted to cultivating the allotment. I find that they make some outstandingly stupid decisions that have very little to do with gardening, however that is another story. 

The most effective official on the allotment is the secretary. He walks around the allotments and checks on each one. Afterwards, he either writes this down or colours in on a plan of the allotments how everyone is doing. If there is a problem with any of the allotments he has a word with the allotment holder especially when they are paying their rent. He says that they are not doing well enough. A little patronizing but it seems to have worked very well. If allotment holders have not then cultivated at least some of the allotment, they are sent a letter. Interestingly, the treasurer of the allotment committee was sent a letter this year much to his annoyance. 

If there is a waiting list it is unfair to hold onto an allotment when you know that you cannot do it. Maybe there should be a way of allowing someone to take it on when you are ill or when work prevents you from doing it. 

The problem with when is the allotment being cultivated and when is it not, is a tricky one. The number of people that come onto the allotment and cultivate a metre square out of a full allotment cannot be said to be cultivating. This is why the secretary is giving people half and quarter allotments when they first allocated an allotment. If they do that well, then they are given larger allotments when they become available. This also means that there are less people on the waiting list for allotments. It encourages them and enables them to build up their expertise before the daunting task of turning a wild allotment around. 

Many of us are experimenting with companion planting and permaculture which leads to unkempt allotments in the eyes of a few. This means that the people on committees need to be fairly experienced in the different styles of growing. I find that many of the committee members are inexperienced in even the traditional ways of growing and this leads to a great many problems. Still it is those that put themselves up for election that will get voted on. 

Our allotment site is not one of the most picturesque. When I first started the majority of the allotments around me were abandoned and high in weeds. We could do what we wanted on the allotment just so long as it did not annoy anyone else. Now we have a waiting list but also uncultivated allotments. After so many years surely we could have worked out a way of giving allotments to committed people that would keep them cultivated.

The allotment and companion planting

This year I have spent some time planting companion plants alongside my vegetables.
I know there is some scientific research for plants like marigold, mustard and maybe chamomile but there seems to be very little research on any of the other recommended plants. I must admit that the poached egg plants that I planted under the sweet peas may have helped them. I would much rather think that it was the inoculated charcoal that was more effective though. I am the belt and braces kind of gardener that uses every technique he can to produce the best results.

The companion planting lists seem to be repeated from web site to web site and book to book with very little passing through people’s brains.

The lists of pests they are reported to be effective against read like the old quack remedies such as snake oil.

Is there anyone that can suggest some good research that has been done on companion planting?


I am always amazed at what academics research, because they seem to go for stuff that is not very good for everyday life. In horticulture research, I think that the funding comes from industry so research will be focused on what they think are important.
My main worry is the thoughtless copying of long lists of companion planting that I have seen in many books and websites.


I find it very difficult to rely on old wives tales about gardening techniques because I have found that many of them do not work. The “plant onions or garlic with carrots to keep away carrot root fly” does not work for me and I have tried it for years. However, each time I hear about a method I have not tried I will give it a go even though my scientific training makes me very skeptical.


Now I have read on http://www.allotments-uk.com/ that planting potatoes next to raspberries encourages blight. What is that all about? I have been reading gardening books and research for years and have not heard about that one. Rubus idaeus the raspberry and Solanum tuberosum potato both totally different species from different parts of the world. Not only that, I am growing potatoes right up to my raspberries this year. I can’t put them anywhere else because it would mess up my rotation.

What fascinates me is that there are very few non cultivated plants within the lists. If there is something in companion planting, and I think there maybe, then surely the fact that a plant is cultivated cannot be the important factor.


Native uncultivated plants, weeds for short, probably have a greater affinity for native mychorrhizal fungi may give a greater help to crop plants than the list plants. Mychorrhiza will be able to transfer any beneficial chemicals to partner plants much quicker, easier and more effectively than diffusion through the soil.
It may be true what people say,
But I keep wondering anyway…

Terra Preta on a cold December day.

Although I am going to go through what is known about these black earths, I think that it cannot be decided how useful this will be for amateur gardeners until we have tried it for ourselves.  This is what several of us are doing at allotments.uk.

Could the research on Amazonian black earths be applied to British soils to increase their fertility?  Research shows large areas of fertile black earths in otherwise very poor rain forest soils.  The fertility of these soils seems to be associated with charcoal added to the soil over thousands of years by indigenous South American civilizations.  This could have been done purposefully or coincidentally when adding midden contents to fertilize fields. Regardless of their motivation, it seems that this has produced a remarkable soil with some strange characteristics. 
It seems that regardless of its use it remains fertile for generations even when these fields were reclaimed by the rain forest.

Ignoring the weeds, this end of the pea rows did not get any inoculated charcoal. 

 This is the end that got the inoculated charcoal. Not the best peas in the world because they were on relatively infertile soil.

However, when scientists add charcoal to soil there is a noticeable reduction in fertility. This is cited as a reason for not developing a slow acting soil amendment from a charcoal base.  How could such a relatively inert substance, which does not degrade substantially over hundreds of years, reduce fertility?

There is some suggestion that charcoal adsorbs or absorbs nutrients in the soil.  It certainly has the capacity to do this having an intricate structure of many small channels giving it an extremely large surface area.

So nutrients may well have a tendency to adhere to the large surface area.  As there is a depletion of nutrients in surrounding areas of soil when charcoal is added to the soil, maybe adding nutrients to charcoal before putting it on soil might mitigate any adsorption or absorption problems that adding "neat" charcoal might produce. 

This could produce a slow nutrient release system.  Affinity of the charcoal for nutrients depends on the condition and type of soil it is in, but I would suggest that this would be a buffering mechanism.  It would adsorb nutrients when they were in surplus but as concentration decreases the charcoal will lose nutrient by a diffusion process maintaining equilibrium with the surrounding soil.
What kind of nutrients could amateur gardeners inoculate the charcoal with to give the maximum long lasting effect on the fertility of their soil?
Several different methods and recipes have been suggested; however I will only give you the method and nutrients that I use personally.  My charcoal, which is just barbecue lump charcoal, is marinated in:

·         Chamomile tea

·         Nettle tea

·         Sweet Cicely tea

·         Worm tea

·         Sugar

·         Blood, fish and bone meal.

The mixture is housed in an old plastic dustbin and left for at least two months.  After this time the charcoal is removed, allowed to dry and then crushed with a bull hammer into pieces no more than 1 cm³.  This gives the charcoal a larger surface area and makes it easier to add to the soil.  I have used bigger lumps but they are cast to the top of the soil continuously by the frost rather than being incorporated within the top 15 cm of the soil. 

There are large numbers of micro pores formed from the xylem and phloem structures within the charred wood and both soil bacteria and fungi could find a habitat in these pores free of predators.

The importance of the micro fauna and flora of the soil cannot be overestimated especially when considering the number of symbiotic or mutually beneficial, relationships there are between micro organisms and crop plants.   There are some tentative indications that mychorrhizal fungi associations with crop plants are encouraged by the addition of charcoal to the soil. Mychorrhizal associations with plants enable them to obtain nutrients from a wider volume of soil than otherwise would be the case, the plant giving the fungi sugars in return. 

My contention is that cultivation disrupts this association and kills off mychorrhiza fungi through cropping, digging and forking.  Adding these fungi to the charcoal may help to replace them in the soil.  A number of scientists suggest that the soil is abundant in spores of these fungi and that adding more is superfluous.  They seem to be basing their assumptions on research into natural ecosystems rather than cultivated environments and I wonder if this still hold true.  

·         So I add mychorrhizal fungi to the charcoal as well.  But only after crushing the charcoal. 

There is some evidence that adding charcoal to compost heaps achieves the same adsorption of nutrients but I have not tried this. 

How much charcoal to add to the soil is another unanswered question and one that we are trying to assess.  There seems to be two ways of adding it.  

·         Spread it broadcast over the soil.

·         Just add it to planting areas in planting holes or along rows of seed drills.  

At the moment I am just adding charcoal to planting areas. 

A further advantage of adding charcoal seems to be its ability to help the soil to retain water while also allowing better drainage. 

 Charcoal is relatively inert in the soil so there is a great opportunity for sequestration of carbon.  The more charcoal that can be added to the soil the larger and better our crop plants will become. All these different advantages of adding charcoal to the soil seem to be both long lasting and cumulative. 

Green manures

I have been using grazing rye as a green manure for several years now. My soil is mostly a sandy clay and obviously fairly easy to work once it has been knocked into shape. Grazing rye comes up in thick soft leaves that easily shade out most weeds.  It also has a very thick mat of fibrous roots.  The advantage of this grass is that it rots down very quickly in the soil.  

Green manures, whichever you use, are useful for a number of different reasons.

• They cover the ground in winter so that nutrients are not washed away by the winter rains.
• They shade out weeds that might germinate during the autumn and winter.
• They add organic matter to the soil which eventually rots down to form humus.  Humus is a black oily sticky liquid that forms films around soil particles. 
• They help to recycle nutrients in the soil.  
• If you use one of the plants from the legume family like tares, clover, field bean or lupin then they will add nitrogen to the soil when you dig them in.  Remember that root nodules formed by the rhizobium bacteria help to fix nitrogen and pass it to green plants.  The nitrogen is therefore in the leaves,  stems and roots of the plants.  If you do not dig in all the plant then you will loose some of the fixed nitrogen unless you put the tops onto the compost heap.  If you burn the tops then you are loosing the nitrogen to the air. 

I dig it into the soil in the spring before planting or sowing seeds.  

You don't need to worry about introducing a weed onto your allotment because the only way that rye grass spreads is by seed and whether you dig in or strim you will not get seeds.  It does not have stolons like couch grass.   I sometimes mix it with tares or clover when I am sowing, although grazing rye does tend to shade these plants out as well. 

Some photographs of the allotment.

Green manures

Chilly December

I have just returned from holiday in Malta and Greece to a very cold England. The ground has been frozen for about two or three weeks now and little can be done in the allotment.

I went to the allotment yesterday with the intention of moving some of the black current bushes. Althought the top couple of centimetres were not frozen, below this was a thick layer of frost. Not the kind of ground to start planting into. The black currents will probably have to be moved in the spring if this weather continues.

Remarkably, I was able to get out some of the parsnips. They were excellent and shows you why thinning out is very important if you want big roots. I also got some carrots. I think that the ground was not so frozen here because of the horse muck I had put close to them.

Beetroot are very small but I harvested them in any case.

I took off some of the Brussel sprouts and I will prepare them today by peeling off the outer leaves. There are some plants that are producing large buds and some that are only producing small ones. I cannot remember the varieties that I planted so I will not be able to ensure I have large buds next year.

They did not burn down my shed on bonfire night which I am very greatful for. The committee put the bonfire closer to Tony's allotment and quite far away from my shed.

Someone however put a load of fireworks on my allotment right where I had planted broad beans. I am not happy. These are the fireworks you stick into the ground. Needless to say I will be asking the committee why they pick on my allotment to do these things without any consultation with me.