As more and more Canadian municipalities ban the cosmetic use of pesticides, many gardeners are left wondering how to manage their lawns without letting them become a haven for dandelions, other weeds and pests. Well, there's good news for these gardeners—and anyone else concerned about pesticide use: almost all lawn problems can be dealt with organically.
Michael Pascoe has been caring for 100 acres of turf, without using synthetic chemical pesticides, for the past 15 years at Cuddy Gardens, a private estate garden near London, Ontario. Pascoe is a horticulturist, but he sounds more like a Buddhist monk on the subject of organic maintenance: “If there are problems with your lawn, you need to ask, ‘Why are they there?'”
The key is to identify the underlying cause—the “why”—of your ailing grass. Quite often the problem comes down to soil depleted of nutrients and organic matter, and lack of aeration. More good news: autumn is the perfect time to give your lawn an organic pick-me-up, which will get at the root causes of turf traumas and ensure vigour come spring.
Organic maintenance in fall basically consists of a trio of tasks: aerating, top dressing and fertilizing. All three will improve your soil, providing a healthy foundation on which your lawn can thrive. (See “The Gentle Approach” on next page)
Along with these three practices, there are a few other fall tasks that may be required, depending on how well your grass has come through the rigours of summer, the main challenges being drought, pests and weeds.
If, for example, there are bare patches, early fall (six to eight weeks before frost) is a good time to overseed. Rake the soil, sow the seeds, then lightly rake again. Top-dress with a very thin layer (about one centimetre thick) of topsoil; water well, keeping the area moist until seeds sprout and the grass thickens.
For pest and weed problems, there are a number of organic products on the market that you can apply in autumn. And here's a heads-up: Lorelei Hepburn, owner of the Ontario-based organic lawn-care company Environmental Factor, predicts that leatherjackets (the larvae of the adult crane fly, which looks like a large mosquito) will be a common pest this fall. She suggests pulling back the sod to look for the greenish brown larvae (see “Sneak Peek” on next page). In early September, there won't be any visible lawn damage yet; however, if it's mid-October, you'll likely see brown patches if there are leatherjackets. It's best to look for these pests in a couple of different places. Another sign of the larvae is the presence of crane flies. If you do find leatherjackets, you can buy beneficial nematodes (microscopic parasites that destroy insect pests such as cutworms and Japanese beetles) to spray on the lawn to control them. Available commercially at select nurseries, nematodes can also be used to control white grubs (the larvae of various beetles), which could be found in the soil at this time as well.