Several decades ago, many homeowners got into the habit of collecting their grass clippings and sending them off to landfill sites. People thought grass clippings left on a lawn could cause diseases and an accumulation of thatch (a compacted layer of organic debris) that could stop water, sun, and air from reaching the soil.
Today's research shows that these old fears are unfounded. In fact, thatch is mostly made up of roots and stems - not clippings - and is caused by over-fertilized, fast-growing grass roots. Clippings left on the lawn provide important nutrients, increase soil fertility, and act as a water-saving mulch. They also save us a lot of time and effort!
You may not be quite ready to transform your property into a wildflower meadow, but simply leaving clippings on your lawn will reduce waste, fertilize your grass in an environmentally responsible way, and provide a much healthier habitat for wildlife.
The following tips on proper mowing and watering procedures will ensure the best use of grass clippings as lawn fertilizer.
• When you mow, cut off just one-third the height of the grass. Your lawn will grow thicker and develop deeper roots if it's not scalped too close to the ground. It will also be more resistant to drought, disease, and insects.
• A good rule of thumb is to grow your lawn at least 9 cm high, then cut it to 6 cm.
• Don't mow during a drought or when the grass is wet.
• Make sure your mower blades are sharp.
• Water your lawn infrequently but for longer periods, rather than too little too often. Otherwise, shallow roots will develop. During long periods without rainfall, give the lawn 2 to 3 cm of water once a week.
• Water your lawn early in the morning - not during the day or in the evening. That way, more water will soak into the soil instead of evaporating. Watering in the cool, moist evenings is not advisable because it can increase the risk of lawn diseases.