Lawns will forgive a summer of neglect if you’ll do something good for them in autumn. Books could be written about this, but it all boils down to three main points, and here they are:
Lawns are made of millions of grass plants growing shoulder to shoulder, and they all need to breathe oxygen. The roots of grass plants take oxygen from soil, and if that soil is dense and compacted, it doesn’t have the pore spaces necessary to hold oxygen. A core aeration machine pulls little plugs of soil out of the lawn, breaking up heavy clay underneath and allowing air to find its way into the root zone. Core aeration machines can be rented, or a lawn service will offer this treatment. The little plugs of soil are thrown on the surface, and should be left in place. Weather will begin to break them down in a week or so, and the plugs can then be batted about with a leaf rake to further disintegrate them. Yes, it looks a bit messy, but be assured you’re doing the right thing.
If the lawn is fertilized only once a year, autumn is the best time. An autumn fertilizer analysis is lower than formulas designed for spring or summer, and garden centres will have bags of the appropriate fertilizer in stock now. The ideal time for spreading fall formula fertilizer is from mid-October until the second or third week of November, when day temperatures are around 10°C, but the ground is still soft. Grass plants won’t be growing in that cool air, but the nutrients will be absorbed by the plant crowns and stored for use in early spring. That means the lawn will get off to a good start next spring. If you want to feed the lawn a second time next year, wait until late May or early June.
With so many grass plants competing for moisture, lawns are vulnerable to moisture stress and drought. Frequent irrigation is one way to sustain a lawn in severe summer heat and drought, but a well-mulched lawn will be considerably more self-reliant. There are many organic materials that make a good lawn mulch, such as a two-inch (5-cm) layer of triple mix or composted manure, but the easiest to find and most cost-efficient material is shredded leaves. Spread dry, crisp leaves over the lawn and pass over them several times with a power lawn mower. The resulting chipped, cut and shredded leaves will form a rough mulch, slipping down between grass blades and composting at soil level. This process can be done several times throughout autumn, whenever dry leaves are available. It looks a bit messy just after the process, but the shredded leaves will settle down in a few days.