- The Great Toronto Tree Hunt
- LEAF Learning Garden
- Let It Bee
- Maple Leaf Forever Tree
- Urban Forest Demonstration Gardens
- Urban Wood Utilization
- Young Urban Forest Leaders Program
- Youth EAB Ambassador Program
- Past Projects
Signs of disturbed soil:
- compacted and hard to dig in
- little or no organic matter (the dark layer near the top of healthy soil)
- hard, clay-like texture with few air pockets
- hard surface that water runs off of, rather than soaking into
What is healthy soil like?
If you live in a newly constructed home, chances are your soil is in need of help! Typical construction practices remove two to three feet of native topsoil, often leaving only hard clay remaining. The clay is then covered with a few inches of soil and sod. This practice wreaks havoc on soil. The subsoil underneath is so compacted that it essentially acts like concrete and plants must struggle to survive.
Soils in natural conditions have many layers – each layer has different chemical and physical properties that have distinct roles in the soil's function. The top two layers are the most important for trees as they contain the nutrients, water, organic matter and air spaces that roots need to grow.
If you have not started to landscape or lay sod yet . . .
You can give your soil an overhaul by mixing in plenty of compost or other organic matter. This process needs to be done BEFORE tree and shrub planting, since digging can seriously damage roots. Use a shovel or digging fork to mix the amendments into the top 10-12 inches of soil. You will need to do this over large planting areas, such as your whole lawn (before sod is lain) or in a large planting bed. It will not help trees and other plants to mix in amendments in small holes at the time of planting. Tree roots grow quickly and need to spread out into the surrounding soil. The small ‘pots’ created by amending only an area large enough for the existing roots when the tree is planted will restrict root growth and negatively affect the health of the tree.
Do NOT disturb the soil around existing trees by digging up the soil. This can cause severe root damage and even death of the tree. Where tree roots already exist, soil amendments must be made gradually. Simply sprinkle a thin layer of compost or well-composted manure on top of the ground, at least as far out as the branches reach.
This organic matter will gradually work its way down into the soil below. Apply again when you notice that most of the compost has disappeared. Always maintain a layer of woodchip mulch around the base of trees as well.
If you have already started to landscape your yard . . .
Follow the steps below. These steps should be carried out regularly to maintain a healthy soil balance.
Mulch around trees and other plants
Leaving soil bare exposes it to the damaging elements of sun, wind and rainfall. Soil that is not covered with plants or grass should be covered with mulch (wood chips, leaves or other organic matter). Mulching with compost is especially beneficial because earthworms and other soil life move through the mulch and help carry these materials down into the soil. Placing mulch around trees and other plants also helps conserve moisture in the soil and limit weed growth.
Leave your leaves and grass clippings
Leaving the leaves that fall from your tree and the clippings from your lawn are a simple step to get organic matter and nutrients into your soil. Grass clippings, which are full of nitrogen and other nutrients, breakdown quickly and provide free fertilizer for your lawn. You don't need a special type of mower to leave clippings on the lawn; just keep the blades on your mower sharp. The City of Toronto no longer collects grass clippings as garbage or yard waste, so the best thing to do is leave them on your lawn.
Fertilize with compost, not chemicals
Chemicals do more harm than good to lawns in the long term - not to mention the harm they can do to our health. Instead of using chemicals, sprinkle a layer (about 1/2 inch) of compost over the entire surface of your lawn and garden in spring and fall.
You can use a spreader or top-dressing machine, or simply sprinkle by hand. This will add organic matter and nutrients to the soil. On lawns, make the spring application at least three weeks before your first mowing. After a couple of years, you can reduce the application to one treatment -- a 1/4 inch layer applied in fall. You can pick up free compost from the City (see below).
Aerate your lawn and water wisely
Removing small plugs of soil allows water and nutrients to penetrate more deeply in compacted or new subdivision soils, helping to speed up the process of soil restoration. Contact an organic lawn care service to enquire about this service.
Sometimes rainfall will provide all of the water your lawn requires. About an inch of water per week in summer is enough. If you do water, one deep watering per week in the early morning is best. More frequent, shallow watering will only encourage a small, shallow root system. Over watering can cause roots to rot.
Signs of soil improvement:
- there is layer of organic matter present; the top layer of soil is darker in colour
- water soaks in rather than running off
- the texture gradually becomes less clay-like and there are more air pockets
- it's easier to dig in (this may take some time)
- there are more worms visible when you dig
- City of Toronto Programs www.toronto.ca
Lawn Care 416.397.5296
- For organic gardening tips try Rodale's Chemical-Free Yard & Garden. 1991. Random House Publishing.