Is burning the best way to get rid of diseased plants?
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 antethesis 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 seems to be the season of fire lighting. A season that culminates on the 5th of November where people vie to get the largest most dangerous pile of flammable material that they can and then proceed to burn it all.
Not only that but insult is added to injury by firing off of fireworks. As if we did not have enough pollution. Why not add a little more heavy metal contaminated smoke to the atmosphere?
‘Oh’ I hear you say, ‘but aren’t they beautiful?’ No. Flowers are beautiful. Gardens are beautiful. People are beautiful.
Garden fires produce carcinogens - cancer producing substances. You loose the nutrients locked up inside the plants when they burn. It adds carbon dioxide to the atmosphere unnecessarily and it dumps pollution onto surrounding allotments. You do not get rid of stuff. It is still there - just changed- and some of it gets onto other people’s 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 wet plant material because I will guarantee that you will not destroy pests or diseases in this way. Heat is one of the ways of killing microorganisms, however I would be surprised if the heat generated and the achitecture of a normal smoky garden fire would be a reliable way of safely disposing of diseased material.
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. Ah but… I hear you say - regardless of the ‘buts’ there are alternatives.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. 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 surounding 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. 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. In any case, it does not seem to have any adverse effect on my vegetables.
Earlier in the 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.
September 8th, 2009 at 5:56 am
I hear you. I don’t bury them. I just have an out of the way area where it all composts. I live on a downslope and it helps keep some of the water from running off entirely and instead soaks into the ground. My yard loves it.
September 8th, 2009 at 8:23 am
I agree, I don’t believe burning is the way to go and I’m always surprised when they suggest it on shows such as Gardener’s World… Especially these days when everyone is trying to be carbon neutral!
November 24th, 2009 at 8:33 pm
I do admit that I have had two bonfires since I took on the allotment - that’s one a year. It has to be done when the pigeon men on the adjacent plots aren’t racing their pigeons (doesn’t do them any good). With a clay soil, I’ve no intention of going down anywhere near the subsoil as I’m just only just getting a workable amount of topsoil after three years (previous tenants certainly didn’t believe in adding compost). And the wood ash on the compost heap is a valuable commodity. However I’ve now burned the backlog of rotten timber that I inherited so that will ensure that there’s no need of more fires. Diseased plant material? In the bag and down the tip when there is anything that I don’t want to compost. We have a visit to the tip about twice a year to get rid of “stuff” that turns up which can’t be used. But yes, I don’t see the point of burning excessively. Certainly not some of the things that other allotment holderss would burn.