Why you should not have bonfires on allotments.

This is one of my rants on bonfires.  

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 - and other pollutants. 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 allotment vegetables. The ground under and around fires is damaged both with the chemicals produced in the fire and the heat.

What do you do with diseased plants? Well one thing I would not do is heap them into a smelly, smoke ridden pile of burning, 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.

It is sometimes said that wood ash is a good source of potash for the garden. It also contains a lot of calcium and a very small amount of trace elements like iron, manganese, zinc and copper. These elements are not produced by the fire; they are in the plants already.  They are concentrated in the ashes because carbon, nitrogen, sulphur and water are being driven off as gaseous oxides.  I would rather have all the nutrients that are locked up in plant tissues returned to the soil.  This is why burying them is much better.  

Composting will not only deal with pernicious weeds, it will also produce a good soil conditioner.  I compost couch grass (Elymus repens); mare's tail (Equisetum arvensis) and bindweed (Calystegia sepium) after carefully drying and turning for at least two or three months.  As a further precaution I compost them in a 1 tonne, FIBC, bulk builders bag, which fits quite snugly into my pallet compost boxes. Grow out of that if you can rhizomes... 

Other weeds will compost a lot easier than this.  There is no need for burning.  There are a lot of nutrients locked up in these weeds that should be returned to the allotment soil.  If you can't  spend the time doing this then put them in the dustbin.

Further more, 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 diseased material to the tip or you could bury it deeply 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 triple 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 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 ancient South Americans 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.  In any case, it does not seem to have any adverse effect on my vegetables.  (I wrote this in 2010 before I found that the technique had been used for years and called hugelkultur. I realise now that I had been doing hugelkultur for years before I knew what it was called.)  

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 (2009) 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 top 6 to 8 inches of top soil are normally well drained. The logs and brush wood seem to leave drainage spaces in the soil which water can flow through easily. 

There is no need to burn woody material on allotment bonfires; as you can see here, it can be very effectively buried to form a raised bed.  The nutrients from the wood will slowly be released into the soil over many years giving sustained fertility to the soil.  

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.  Burning, including your allotment bonfire, just short circuits the process and produces greenhouse gases straight away with no opportunity for carbon storage or capture.

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.  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  Teflon and 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.

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 challenging 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. So why make it worse by lighting bonfires on your allotment?

It is the same science that makes your mobile telephone work, your fridge 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 and my vegetables. 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, don’t believe that cigarettes cause cancer and don't believe that your bonfire smoke is affecting my vegetables. 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. Or light a fire and put pollution all over them.  

Science does not prove things; it just interprets data, hopefully reasonably. 

Totally agree bad data produces bad interpretation.  Questioning data is a fundamental part of science and is going on all the time. Scientists always should challenge data, its collection and interpretation. Very legitimate part of science.
However, 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, including lighting bonfires, 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. 

So why add to the problem by lighting allotment bonfires?  

Take it home and put it in the bin.