Some harmful chemicals are permitted in organic gardening (although you are encouraged only to use them occasionally if you feel you must). Others, such as glyphosate are regarded as anathema under all circumstances. Copper, a very toxic fungicide was once accepted in organic gardening but can now only be used on organic farms with special permission. Some permitted organic remedies, such as copper bands and dry material such as grit, eggshells or wool to deter slugs, really don’t work very well in the medium to long term. Other approaches, such as knocking aphids off broad beans with a water jet are effective (if repeated daily) and quite fun.
Generally, we have a lot to learn from organic practices, especially the suggestion of being a bit easy going and accepting a few weeds and holes in the leaves of your veg. What isn’t clear is the impact of very occasionally using an organically forbidden chemical such as glyphosate, according to the instructions, in circumstances where hand weeding is impossible, Typical examples include ground elder established among the roots of shrubs or deep-rooted bindweed which you can train up a stick and then treat safely inside a plastic bag.
The truth is there have not yet been any rigorous controlled experiments looking into the actual biodiversity impact of such small-scale use. The same is true about judicious use of insecticidal sprays to defend choice plants threatened with pest invasions. This is probably the number one research question
for wildlife gardening – and it would need a very large and long-term experimental study to resolve. At the Wildlife Gardening Forum we advise people not to use chemicals unless they feel they have to, and in the great majority of cases, especially with insecticides, you really won't need them.
Organic growers invoke the precautionary principle to say that if we don’t know we should assume the worst. Wildlife gardeners can weigh up the pros and cons and decide for themselves when such chemicals are considered on a small and infrequent basis. Using a prohibited chemical may stop you calling yourself an organic gardener, but it definitely doesn’t stop you being a wildlife gardener.
Jennifer Owen deliberately managed her exceptionally well-studied garden conventionally, although by choice she was tolerant of moderate weed growth and didn’t use pesticides beyond slug pellets. While not an organic garden as such, her management was a model for wildlife gardeners everywhere, and she recorded very large numbers
of plants and animals . The high biodiversity found in “ordinary” gardens by the Sheffield BUGS study suggests that typical non-organically managed gardens are excellent for wildlife.
It’s great to garden fully organically if you wish, but you will probably have just as much wildlife even if you do use chemicals occasionally.
Page written by Steve Head: reviewed by Ken Thompson