We love our lawns, but do you consider how many chemicals you apply to your grass every year, asks Val Bourne, AG’s organic wildlife expert
When we moved to Spring Cottage 12 years ago, the old shed contained a cocktail of chemicals, including DDT – an organochlorine pesticide that was banned in Britain in 1984.
This chemical was widely used in agriculture as a seed dressing from the late 1940s onwards. By the 1960s it was known to be poisoning and killing small birds in large numbers, and this partly led to a sharp decline in birds of prey.
It wasn’t just a question of supply and demand, though – fewer songbirds, therefore fewer birds of prey – as the real reason was far more complex.
Scientists working at the now defunct Monks Wood Experimental Station in Huntingdon, Cambridgeshire, realised that eggs being laid by birds of prey were very soft-shelled and fragile. This was attributed to a form of chemical poisoning. Birds of prey were ingesting small birds and mammals, and were accumulating the toxin in their body fat because they were at the top of the food chain.
Pigeons were also accumulating high levels of DDT, although it didn’t kill them. Peregrine falcons, which often feed on pigeons, were badly affected.
A publication called Planet Earth (Summer 2015) ran an article called ‘Watching the Birds’ by Tom Marshall. It recorded that “by 1961 more than half of the peregrine nests… occupied during the 1930s were empty.”
It’s different today. Peregrine levels are now higher than they were pre-war and many a city cathedral has resident peregrines keeping pigeon numbers down. However, if DDT hadn’t been banned, the peregrine may well have been on its way to extinction.
What has this got to do with gardening? Well, human beings are definitely at the top of the food chain and they’re also vulnerable. To go back to Planet Earth, “it was then realised that organochlorines can harm human health after travelling along similar environmental pathways and accumulating in our bodies, and may be associated with problems including cancer and diabetes”.
It may surprise you, then, to know that more chemicals are applied to lawns than to any other part of the garden. Yet this is where your pets walk, and your children and grandchildren roll and cartwheel. I’m fully for lawns, and when the Best Beloved deigns to mow ours it’s the equivalent of a Paul Daniels’ magic act, because it sets off the garden.
Our lawn is not weed-free, but I love the blue haze of self-heal (Prunella vulgaris) that appears in August and I’m regularly adorned with daisy chains, courtesy of my three granddaughters. I also get to see buzzards, kites, kestrels and sparrowhawks close to home.
Before you use any chemical, think about where it could end up! The website Breastcancer.org has a section on Exposure to Chemicals for Lawns and Gardens, with lots of gardening tips.