Lawn Care
By Sarah Coulber
Grasses, like other plants, thrive under optimal growing conditions. But if you’re not careful, they can become susceptible to a variety of problems and become dependent on chemical pesticides and fertilizers — resulting in a hit to your wallet and to the environment. With a bit of forethought and planning, however, you can have a lush green lawn ― and grow it organically. Here’s how:
Selecting, Sowing and Over-seeding
Before buying grass seed, make sure you match it to the light and moisture conditions of your garden. You can mix different types of grass seeds to cater to the different areas of your garden, to discourage weed growth and to improve your lawn’s chances of withstanding insects and disease.
For cool-season grasses that germinate quickly and suit our northern climate, choose perennial rye grass and fine fescues. They grow well in the spring and fall and go dormant during the hot mid-summer. And fine fescue grass is often insect-resistant because it carries an internal fungus.
Kentucky bluegrass is a common choice for lawns for its aesthetic appeal. However, it is a higher maintenance grass that requires full sun, well-drained soil, and more water and nitrogen inputs than some other grasses. If you want to grow it, mix it with other grasses for improved strength. Ask your local nursery for advice on the best mix for your garden.
Over-seeding, or adding new grass seed, each year helps to keep your lawn lush enough to out-compete any weeds trying to grow. Over-seed in early spring or in late summer/early fall to give the young plants about six weeks to get established before the extreme conditions of summer or winter set in. Apply 900 g (2 lbs.) per 1,000 square feet — more if the lawn is thin (1.3–1.8 kg/3–4 lbs.). You can increase the chances of the seeds germinating by giving the area a light raking to remove any barriers to the soil. Keep seeds and seedlings moist until they are well-established, which takes about three to four weeks, and remove weeds by hand.
Mowing
Cut the grass at a height of 7–10 centimetres (3–4”), removing no more than one-third of the grass length at each cutting. What most homeowners don’t realize is that the height of the grass is proportional to the depth of its roots, and to have a healthy lawn you need healthy roots and leaves. Grass that grows in shade requires a particularly long leaf blade for greater sunlight gathering and food production. If you cut the grass too short, you work against the plant by:
- reducing its ability to make its own food because it collects less sunlight and carbon dioxide from its leaves;
- decreasing the plant’s ability to get water and nutrients from the soil because of shallower roots;
- increasing recovery time after periods of drought and dormancy;
- weakening the grass and making it more susceptible to weeds and insects;
- allowing more sunlight to the soil, which can burn sensitive roots, thus weakening or killing the plant and allowing weeds to move in; and
- letting moisture evaporate more quickly, which means you spend more time and money watering the lawn.
Be sure to keep the lawn mower blades sharp to minimize stress on the plants. Paul Sacks, author of Handbook of Successful Ecological Lawn Care, recommends getting blades sharpened after 8 hours of cutting. Check with your local hardware store to see if they provide this service.
Leave grass clippings where they lie. Grass clippings decompose quickly through soil organisms ― critters that break down organic matter and improve soil structure and aeration, thus allowing more nutrients to be available to your lawn. Thatch from clippings is usually a problem only if your soil is very low in microbial activity or if you’ve just cut extremely long grass. If you do get large clumps, mow again to break them up. To encourage more soil organisms, avoid chemical and organic pesticides and chemical fertilizers. Instead, apply good rich compost.
If you don’t want to keep your clippings on your lawn, rake them up and put them on your compost pile or use them as mulch in your garden beds.
Watering
How you water your lawn seriously affects its health. Shallow watering causes the roots to grow upwards toward the water. This makes them susceptible to scorching from the sun and causes them to exist in the upper level of the soil where water evaporates quickly. To promote a lush lawn with deep roots that better resists weed, drought and insect damage, water deeply, 2–3 cm (½–1”) once a week. If you have very sandy soil, however, you may need to water more often until you can build up the soil with compost applications. You may also need to water more where your grass grows under large trees. A better solution would be to replace the grass with mulch under trees and shrubs, at least out to the drip line.
Use an empty tin to track how much rain falls in a week and to determine how much water you need to add, if any. To know if you are watering deeply enough, dig about 15 cm (6”) down to see how dry or moist the soil is. If it is bone dry right after watering, you need to add more water.
Let the soil dry out between waterings to prevent disease and allow for good air circulation. To reduce evaporation, water in the early morning. Refrain from watering your lawn during times of dormancy, such as in the heat of mid-summer, to make it harder for any germinating weed seeds to survive. This also discourages the eggs and grubs of lawn pests such as the Japanese and June beetles.
Fertilizing
Plants require nutrients to grow and to be healthy. Fertilizers are wonderful allies when used correctly and in a manner that suits the nature of the plant in question.
While synthetic fertilizers can give you a good show, they usually aren’t worth the money in the long run. Many release their nutrients too quickly for the plant, and much gets washed away in the rain, polluting our waterways. Quick-release chemical fertilizers, with their high nitrogen content, stimulate excessive top growth without sufficient root development. The grass becomes weak and susceptible to a variety of weed, disease and insect problems. It also needs to be mowed more frequently.
Organic fertilizers are typically safer and more beneficial than chemical ones. They release macro and micro nutrients slowly and steadily, nourishing the soil and keeping soil organisms healthy. Adding organic material to the soil improves air circulation, water retention and drainage. Examples of organic fertilizers include compost, old manure, fish emulsion, and grass and leaf clippings left on the surface, which help to break up organisms. If you use manure from farm animals, you need to let it sit for a few months before adding it to your lawn, as fresh manure can burn roots. Compost has multiple benefits. It can be made at home at no cost and it reduces the amount of waste going to landfills. If you buy organic fertilizer, look for a 3-1-2 ratio of nitrogen-phosphorus-potassium.
Many lawn experts feel the best time to fertilize your lawn is in the fall. Apply about 0.6 cm (¼”) or more with a shovel and rake. It is also helpful to provide a small amount of nitrogen during the year — leaving grass clippings is the perfect way to do this.
Aeration
Compacted soil prevents adequate water retention and air circulation ― two elements that plant roots require for optimum health. To check your soil, push something like a screwdriver into the ground. If it goes in easily, your soil is okay. If you have to push very hard, your soil may be compacted. Some causes of compacted soil are heavy traffic and an insufficient number of soil organisms.
One way to aerate your soil is to remove plugs from the soil, approximately 5 cm (2”) deep throughout your lawn. But this method is generally not recommended as too much air can speed decomposition of organic matter leading to increased compaction.
The best way to aerate is to encourage organisms (earthworms and microbes) with a thin layer of compost and to avoid pesticides and chemical fertilizers, especially the quick-release ones.
And remember — leave those grass clippings on the lawn!
Photograph: Sarah Coulber
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