Whether consisting of turf grasses, clover or thyme, lawns are usually at their best during the cool and rainy days of late spring and fall. So when the summer heat arrives, your yard cover can take a hit. Here’s how, with just a bit of attention, you can keep it in great shape all summer long.
A cool, rainy summer may feel dismal from a human point of view, but your lawn loves it—that’s when it’s at its lushest. When the sun blazes down day after day and temperatures continue to soar, evaporation increases and those green blades begin to turn yellow, then brown, until all growth stops. But your grass isn’t actually dead—it just enters a state called “summer dormancy,” until cool and rainy weather returns in the fall.
If you want your lawn to remain green all summer, you have to compensate for the decreased rain and increased evaporation by watering it. Giving the lawn a quick spritz now and then will only stimulate shallow rooting, leaving the lawn’s roots exposed to heat and drought damage. To maintain a healthy, green lawn, you need to space the waterings out and always water deeply to encourage turf roots to reach deep down into the soil where it’s cool and damp.
Here’s what to do: Place a rain gauge (available at any hardware store) on the lawn. If less than 2.5 centimetres of rain falls during the week, then you’ll need to compensate for the difference. Turn on the sprinkler or irrigation system and let it run for about 45 minutes (depending on your water pressure and the amount of rainfall), stopping when the gauge reads 2.5 centimetres. That’s perfect for clay and loam soils, but if your soil is sandy, it’ll take a bit more work. Sand holds little water so whatever you apply, or what’s supplied by the rain, doesn’t stay long in the root zone. This means that you’ll have to water more often, about every three to four days, for 45 to 60 minutes each time.
The Law is The Law!
Many municipalities implement summer water use restrictions. Check with yours to find out if there are any guidelines specific to your region. The best time to water is in the early morning when the soil and air are at their coolest, as there will be minimal evaporation. You can add a timer to your lawn sprinkler or irrigation system so it will turn on and off at the appropriate times.
Here’s an easy tip for a healthier summer lawn: Adjust your mower’s blades so it trims higher in the summer. Mowing as short as a golf green, down to 5 centimetres or less, is never good for a lawn; the effect can be devastating in hot months. That sort of scalping reduces the lawn’s vigour and lets the sun penetrate to the roots, burning them. It also heats the soil (not something lawns like!) and increases evaporation: a veritable chain reaction of disasters for the lawn.
Instead, let your lawn grow to about 10 to 11.5 centimetres, then mow it down to 7.5 centimetres. The longer grass provides shade for the roots and you’ll also be cutting back less of the energy-giving leafage. You may need to mow every five days to once a week in the early summer, but when the heat rolls in, the lawn’s growth will slow down and you’ll rarely need to mow more than once every two weeks.
Don’t rake up lawn clippings: If left where they fall, they will quickly decompose and disappear from view. This is called grasscycling and lawns love it! The clippings gently enrich the soil with minerals while also keeping the roots cooler and reducing evaporation. And your municipality will thank you, too. Bags of clippings left at the curb are expensive to pick up and bog down waste removal processes.
Toward the middle of summer, you may notice a curious phenomenon: a circle of mushrooms that emerges from the lawn. This is called a fairy circle, because people once believed they were caused by fairies dancing on them under a full moon. Today, we know that this circle of mushrooms is a natural occurrence due to the presence of long-established soil fungi. If you dig into the soil inside the circle, you’ll see the presence of white filaments: this is the mycelium, or the vegetative part of the fungus. The white or brown mushrooms that pop up are the mycelium’s fruiting bodies (spore-producing organs). There are more than 60 species of mushrooms that are known to produce fairy rings.
Often, the lawn within the ring itself is greener than the lawn outside of the ring because the fungus releases nitrogen that stimulates green growth. On the other hand, if your lawn is well fertilized and watered in dry weather, the ring will be largely masked, as the lawn will be about the same colour everywhere. Regular watering and fertilization are about the only treatments that have much of an effect because it's very difficult to eliminate this type of fungus, other than by removing and replacing all the soil in and around the ring to a depth of 30 centimetres.
So, what should you do? If the mushrooms annoy you, try simply mowing them down or knocking them over with a rake. They typically won’t reappear (until the following year) and soon the lawn will again be evenly green all over.
Fairy rings can last for years, growing annually and sometimes eventually reaching up to 10 metres in diameter. Rather than fighting it—a battle you're likely to lose—it's better to learn to accept it as one of nature’s curiosities, one you’ll be able to observe on your lawn. Lucky you!
White grubs are the larvae of various beetles—June bugs, Japanese beetles, rose chafers, etc.—that live in the soil under the lawn and feed on the roots. In small numbers, they don’t cause any significant damage, but in larger numbers, the lawn will turn a sickly beige colour. The problem is often signalled by the presence of skunks or raccoons digging holes in the lawn in search of the larvae. You can also try pulling on the yellowing lawn; if a clump comes out in your hand, it’s a sign that the white grubs are at work. Dig a little deeper and you should see the little critters themselves. (White grubs do the most damage in sandy soils—something to consider when you buy your next house!)
If you maintain your lawn with regular and deep watering, proper fertilization and relatively high mowing, it should be healthy and better resistant to white grub damage. In June and July, the female beetles are looking for places to lay their eggs, so avoid shining any artificial light on the grass at night. Light attracts them and can make the problem worse.
Until recently, the main treatment available for white grub control was an application of parasitic nematodes. This treatment is still available and should be applied according to the manufacturer’s recommendations. Note that nematodes can be very slow before having a noticeable effect: you'll rarely see much of a difference before the second year. A new product, a bacterium called Bacillus thuringiensis galleriae or BTG—sold under the trademarks GrubGONE and Grub B Gon Max—is more effective in most cases and provides results more quickly. It can be applied at any time from spring to late fall. Just apply it with a lawn spreader, as you would fertilizer, then water well. You should expect to see results in a few weeks.
Say No To Summer Feeding
To enjoy a lush green lawn all summer, you’ll have to fertilize. When grasses have an easily accessible source of minerals, including nitrogen—the first number on a bag of fertilizer—they’ll be as green as they possibly can be. However, summer isn’t the right time to apply fertilizer. Turf growth slows down due to heat and drought and your lawn won't be able to efficiently absorb the minerals you apply. Not only is a mid-summer application essentially useless, but it can even burn the roots and cause the lawn to yellow. Ideally, you’d apply a slow-release lawn fertilizer in May (mid-June at the latest), certainly not in July or much before the end of August. In most circumstances, this single application of spring fertilizer, combined with grasscycling, is all you need for a healthy, luxuriant lawn. You can also do a second application of fertilizer at the end of summer (late August or early September) when temperatures begin to fall. Even though manufacturers offer fall lawn fertilizers, the same one you applied in the spring is perfectly acceptable for fall use.
Sharp Blades Greener Lawn
If you think your lawn isn’t as green as it could be, sharpening the mower blade might be all you need to do. A sharper blade cuts the grass neatly, without leaving a visible scar, while a dull blade shreds the leaf tips as it mows, spreading dead brown tissue that gives the whole lawn a greyish cast.
Mow Without Damaging Trees
When mowing your lawn, be careful never to bump the trunk of any trees with the mower, especially young ones with thin bark. Such contact, however minor it may seem, can injure the bark and cause it to detach from the trunk, which opens the door to harmful fungal infections. Worse still are string trimmers, used to cut the grass at the base of the trunk that the mower can’t reach, which often cause more damage than a mower. A damaged tree rarely recovers from this kind of injury and will slowly decline over time. These seemingly minor mechanical injuries are the main cause of tree loss on home lawns.
Fortunately, preventing this kind of damage is super easy. You can simply place a tree trunk protector—a tube with air gaps—around the trunk. They’re sold in garden centres and hardware stores everywhere. Or, remove a circle of grass around the trunk and replace it with a layer of ornamental mulch 7 to 10 centimetres thick. That way, no grass will grow near the trunk and there will be no reason to approach it with a mower or trimmer.
And there you go! With a bit of attention and relatively little effort, you can have a lush, green lawn all summer long.