See also http://www.urbanfoodjustice.org/social-platform/soil-quality/ for presentations etc on soil quality.
Most soil, as long as it’s not waterlogged or contaminated can be used to grow food – though you may want to improve the texture, drainage or nutrient quality.
There are three types of soil test:
- acidity (ph) test, which you can buy cheaply online, or from a garden centre. This tells you if you might need to add lime, but most Leeds soils are slightly acid, which is fine for most veg.
- test for nutrients (most people would routinely add some plant food for veg growing)
- contamination test – see below.
Simple test for Leeds soils http://www.keirg.freeserve.co.uk/diary/tech/soiltype.htm
Soil ph for veg http://www.keirg.freeserve.co.uk/diary/tech/fertile.htm
DIY soil testing http://organicgardening.about.com/od/soil/a/easysoiltests.htm
Testing and improving your soil http://www.growveg.com/growguides/soil-types.aspx
See Horticulture for more on soil preparation
Most places – especially gardens and allotments which have been used for veg in the past – are safe to grow in, though if you think your site was ever used for industry (slaughterhouse, garage, paint works, tannery, incineration etc), might have had a stolen car burned out on it, or been used for fly-tipping, it’s probably best avoided. If in doubt, you have three options:
1) Contact the Council for advice
LCC say: ‘If a group are considering using an area of previously uncultivated ground as allotments then they can always ask us what we know before going ahead. A good map, which depicts exactly the area to be cultivated, would be required.”
Leeds City Council Contaminated Land Department http://www.leeds.gov.uk/council/Pages/Contaminated-Land.aspx
Leeds City Council presentation on soil contamination to Urban Food Justice Project – see Resources
2) Conduct a contamination soil test
This is usually very expensive and you really need to do one every square metre or so to be sure. Feed Leeds is hoping to secure funds for a community soil testing service, but this is still some way off.
Guide for Soil Testing in Urban Gardens (Toronto) http://www.pkc.gov.uk/CHttpHandler.ashx?id=20664&p=0
3) Isolate any soil that could be contaminated
LCC advise “Allotmenteers should only need to consider isolation of the existing soil if there was anything wrong with it, or potentially wrong with it, based on a reasonable deduction from available evidence. Buying soil for raised beds is not sustainable if the existing soil is OK, and the amount required could make this very costly.”
If you do decide you need to isolate, this is normally done with a strong barrier (usually plastic sheeting or clay) with the new soil placed on top. One good way to achieve this is to create raised beds (at least 0.5m deep), or use stand-alone planters.
There used to be a supply of free growing material in Leeds (from Yorkshire Water, at Esholt) made from ‘phytoremediated’ green and brown waste, which is cleared for growing garden plants, but not veg as yet (though we understand it to be safe, and that it should be accredited as such in due course) – though this project is currently stalled. You can buy soil and other growing media at most garden centres.
See Raised Beds, Containers etc
Federation of city farms and community gardens contaminated land guidelines http://www.farmgarden.org.uk/publications/135-contaminated-land-guidelines
Leeds City Council, Contaminated land Inspection strategy http://www.leeds.gov.uk/council/Pages/Contaminated-land–inspection-strategy.aspx
Phytoremediation uses natural processes to remove toxins, but is not recommended for veg growing activities.
Phytoremediation (USA) http://www.clu-in.org/download/citizens/a_citizens_guide_to_phytoremediation.pdf
There is some pollution from traffic fumes, though the situation is much better than it was when we used to put lead in petrol. Generally speaking, the further your site is away from traffic the safer it’s likely to be. Local studies have suggested that washing the produce thoroughly should remove most chemicals, though brassicas (cabbages etc) have been shown in some research to take up more heavy metals than other veg, so if you are growing very close to busy road you could always avoid them of you wanted to.
More information http://ec.europa.eu/environment/integration/research/newsalert/pdf/291na1.pdf
Dogs and Cats etc.
Animals should really be kept away from veg patches to minimise the risk of contamination from faeces. If you have a cat problem you can use netting over beds, or deter them by sticking holly or other thorny cuttings between your plants (birch twigs scattered on the soil work surprisingly well). Solar-powered sonic scarers are also available (which are even supposed to deter squirrels, foxes and deer). Always wash your hands thoroughly if you do encounter any poo, and always wash your produce as a matter of routine.
Horse manure is good for plants and safe to handle.
More information http://www.thriftyfun.com/Growing-Vegetables-Where-Pets-Have-Pooped-or-Peed.html
Five Ways To Keep A Dog Out Of A Garden Bed http://www.gardeningknowhow.com/plant-problems/pests/keep-dog-out-of-garden.htm
Please advise of any broken links, or links you think should be included here.