Summer is the season for outdoor play — so why is it that so many lawns wither and die during this time of year?
The truth is that not all grass varieties love the summer sun and heat. In much of the world, cool-season grasses dominate lawns, and these varieties enjoy their active growth periods during spring and fall. This means for much of summer, cool-season lawns are dormant, and some even slip into death.
You can tell that your lawn is a cool-season lawn based on your regional climate and your lawn’s typical behavior. Cool-season grasses grow best when the soil is around 50 degrees Fahrenheit, which occurs when the air temperature is between 60 and 75 degrees Fahrenheit. Typically, homes in the northern third of the U.S. — in New England, the upper Midwest, the High Plains, Northern California, and the Pacific Northwest — will have cool-season lawns, and homes in the Transition Zone — the lower Midwest as well as the northern Southeast and Southwest — could have cool-season grass or a mixture. While a qualified lawn care service can identify your precise lawn variety and give you tips and tricks for maintenance, your lawn is likely dominantly cool-season if it starts growing just after the last frost in spring.
If you want to make the most of your lawn this summer, you need to work to keep it alive and thriving. Here’s how.
Keep It Long
Across the board, cool-season grasses like to grow longer than their warm-season counterparts. This is because cool-season grasses tend to grow in areas that lack warmth; thus, the longer greenery above the surface helps trap warm air and moisture near the soil, helping the plant grow. The most common cool-season grasses, tall fescue, and buffalograss, like to be left as long as three inches, while other cool-season varieties, like Kentucky bluegrass and ryegrass, like to be a bit shorter at about 2.5 inches.
However, just because cool-season grass likes to be left long doesn’t mean you can neglect your mowing duties. You should be mowing your lawn at least once per week during growing seasons, perhaps twice if your lawn is particularly active. Mowing this often prevents grass from getting too long, which can weaken the plant in various ways.
First, when grass grows too long, it needs more nutrients to support that growth, and lacking enough, it will start to wilt and die. Additionally, too-long grass is a pain to mow because you should never cut off more than one-third of the greenery in one swoop. Doing so will shock the plant, potentially causing patches to die or else inhibiting its ability to heal promptly. If you let your grass grow too long, you must mow more often, chopping off a smaller amount until you reach the proper height.
Even though the summer is hot, you probably don’t need to give your lawn more to drink. Cool-season lawns typically live in environments that naturally get good precipitation, even during the summertime. In most places, seasonal rains are enough to keep a lawn alive, and by giving your lawn extra water through sprinklers or a hose, you risk drowning it. When cool-season lawns sit in swampy conditions for too long, they attract pests and fungal diseases, which kill the grass. Thus, overwatering rather than underwatering should be your primary concern.
Of course, climate change is altering summers across the world. If your summertime is mainly dry and you suspect your lawn isn’t getting enough moisture, you should perform a simple test: the tuna can test. Place empty, shallow containers, like tuna cans, around your lawn. Every evening, measure the amount of water collected in the containers. Over a week, the containers should collect about 1.5 inches of water. If they haven’t, you can supplement your water sources — but you should do so infrequently, only once or twice per week.
Finally, a lawn lesson you might not be happy to learn: Grass doesn’t much like to be walked on. Excessive traffic causes the lawn’s soil to compact, making it much harder for roots to grow and acquire nutrients. Over time, compaction problems result in a lackluster lawn and even eyesores like dead patches. You can tell that your lawn has a compaction issue if you can see a path of dead grass where you and your family regularly walk or play.
This isn’t to say that you can’t step on your lawn at all. The grass is relatively robust — but heavy activities, like driving vehicles or using heavy toys, will exacerbate compaction. If you expect to have an active summer on your lawn, you should plan to aerate your soil at the end of the season. If you can’t or don’t want to aerate, try to anticipate the bulk of your summer fun for the pool, the porch, or other spaces in your yard.
The healthier your lawn is at the start of the summer, the more effectively it will survive all season long. Thus, summer care doesn’t start in June and end in September; you need to make lawn care a year-round priority or hire someone who will.