Cool-season grasses grow primarily in the spring and fall and will go dormant and turn brown during droughts or hot weather. Most cool-season grasses will survive this dormancy, but a few introduced species will not. If you want your lawn to remain green during the summer and ensure its survival, you will need to provide it with at least 1 inch to 1-1/2 inches of water each week. Since most sprinklers only deliver about 1/4 inch to 1/3 inch of water per hour, plan to water your lawn at least four hours a week. Be careful not to provide more water than the soil can absorb, as it wastes water. You should also avoid watering your lawn too frequently because it will cause your lawn to develop a shallow root system.
If you are planting a new lawn, it is important to consult with your local greenhouse to find out which types of cool-season grasses grow best in your area. For best results, seed your lawn in the fall, sometime between August 15 and October 31. It is possible to seed in the spring, but this generally does not allow the seed to develop a strong enough root system in order to survive the summer. If you must plant in the spring, provide a temporary cover (such as annual ryegrass) or plan on over-seeding areas that do not survive in the fall.
Cool-season grass seed should be planted heavier than other grasses. Apply one-half the seed in one direction and the second half at a right angle. Then, lightly rake the seed in the soil and water the soil. Seed should be watered regularly until the grass is tall enough to be mowed — about four inches high.
To ensure the greenest lawn, you will want to fertilize four times a year: March, May, September, and October. However, some lawns will do fine if you fertilize in May and October. Before doing any fertilizing, have your soil tested to evaluate its pH and nutrient levels. When fertilizing in March, it is important to use a fertilizer that is lower in nitrogen. Too much nitrogen will cause the grass to grow rapidly, which depletes its energy reserves and makes it less able to survive the summer. This also applies to crabgrass preventatives, which may contain a fertilizer. Purchase a variety that does not contain fertilizer and use it in late March or early April.
Fertilizing in September and October is very important because it will keep your lawn greener longer and allow it to develop thicker with a better root system. When fertilizing in May, use a product with nitrogen that is at least fifty percent in a slow-release form.
Of course, the drawback to having a healthy lawn is the mowing. Cool-season lawns need to be mowed when they are between 1-1/2 inches to 3-1/2 inches high. But then, there has to be some penalty for having the best-looking lawn on the block.
If all this seems a bit overwhelming, you can find a recommended lawn care service on Kudzu. Then you won't have to worry whether your thumb is green ... or brown.