KC Gardens

How to keep your lawn alive during the hot, dry summer

Bluegrass and fescue, the varieties common in Kansas City lawns, struggle in hot, dry conditions.
Bluegrass and fescue, the varieties common in Kansas City lawns, struggle in hot, dry conditions.

Summer has arrived, and the dog days are here to stay for a while. This year the hot, dry conditions got off to an early start, and they’re putting stress on lawns.

Bluegrass and tall fescue prefer a cooler, moister environment. Under stress they grow at a much slower rate, which is not conducive for the food production the plants require.

Compounding the problem is the fact that food for the grass plants is stored in the roots and crowns. Roots quickly decline during periods of heat and drought, and as a result there are fewer roots in which to store food, and therefore less food.

Root systems can also decline as a result of ill-timed fertilizer application. Over-fertilization in the spring encourages growth when the grass is not inclined to grow because of increasing heat and decreasing moisture. This leads to the plant’s system working harder, using up more of the stored food and thus weakening the valuable plant resources and roots.

Cool season lawns naturally would go dormant during periods of summer stress. We trick them into remaining green and overcoming the loss of stored food and energy by watering.

Timely watering will prevent the turf from turning brown. High temperatures and the hot sun quickly dry out the upper surface of the soil, the area where most of the grass roots are thriving. It is important to replenish this moisture for a lush, green lawn.

Once you have started watering to combat heat, it should continue to reduce stress on the turf. Apply every few days to replace moisture lost to evaporation. This will require about 1 to 1  1/2 inches of water a week.

Choosing not to water is another option. The lawn will become dormant and turn brown. However, dormant grass still uses and needs water to stay alive. A thorough soaking every few weeks keeps the plants hydrated and prevents death of the grass crowns.

Proper mowing is another heat management strategy. Keep the mowing height high; 3 to 4 inches for best results. Longer leaf blades help protect the turf by shading the soil and making extra energy for the plant. Mow as needed; the shoot elongation slows greatly during hot weather.

Hopefully these dog days will not last long. September’s lower temperatures and increased rainfall are the best cure for a stressful summer.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? Email them to garden.help@jocogov.org.