Cool-season grasses, the kind you’ll find in most Minnesota lawns, grow best in the cooler temperatures of spring and fall and are dormant in the summer. Unlike warm-season grasses, Minnesota lawns tend to benefit greatly from a late summer fertilization, which improves their appearance by promoting recovery from mid-summer stress.
The goal isn’t to shock the grass out of dormancy, but to boost its density and general health in preparation for the colder months. However, late summer fertilization needs to be done at the right time and done correctly to be truly effective.
When to Fertilize Your Lawn in the Summer
The University of Minnesota lawn care calendar recommends fertilizing Minnesota lawns in the late summer to the early fall—early August through mid-October. Obviously, that’s a wide timeframe, so the exact date your lawn will benefit from fertilizer will depend on its specific needs. September is a popular time for many homeowners.
The calendar also warns against applying fertilizer in the scorching mid-summer months, as the hot temperatures can cause fertilizer to burn the plant. Too much growth during the primary dormant period will stress the grass, and it will be unable to maintain the heavy growth. Late summer or early fall fertilization helps the plant improve water retention to recover from the hot summer stress.
Use a Fertilizer High in Nitrogen
Nitrogen, phosphorus, and potassium are the nutrients your lawn needs in the highest quantities. Phosphorous and potassium are most useful for helping new lawns get established, as they enhance root and stem growth. For cool-season grasses, Perdue University suggests using a nitrogen-rich fertilizer in the late summer or early fall, which will improve the density and green color without causing too much of a growth surge.
It can also be a good idea to get a soil test to determine if there are any other nutrients your lawn is lacking. Buy your fertilizer with nitrogen and these nutrients in mind.
Most fertilizers require a light watering after application to help break down the nutrients and move them into the soil. Avoid overwatering—the general recommendation for watering lawns is one or two inches a week—and avoid fertilizing if you’re expecting heavy rain. Too much water can wash away the fertilizer, undoing your hard work.
Fertilize in the Morning
Morning is the best time to fertilize your lawn for a few reasons. Because the grass needs to be watered in conjunction with fertilizer application, you need to ensure you lawn has time to dry out before nighttime, or disease can take root. Watering in the afternoon may seem like a good idea, but the hot sun can evaporate the water before it can benefit the grass.
In addition, morning temperatures are cooler. That, combined with the presence of morning dew, will help keep your grass from burning.
Lawn care schedules can be a lot to juggle during a busy summer. Find yourself getting overwhelmed? Call Land Concepts for professional lawn care services and get your Minnesota lawn good to grow.