Once the outside air temperature is in the 80 degree + range, cool season grasses slow or stop their growth, no amount of water, fertilizer or begging will make them grow any faster or any greener!
If you wish to keep your lawn green and healthy all summer long here are a few tips you can follow:
Lawns need at least 1” of water per week. Even if you have an irrigation system you need to check the amount of water the system is providing to your lawn. A rain gauge or a straight sided can, like a clean tuna or cat food can placed on the lawn will let you know how much water is being applied. Remember to check all areas of the lawn as irrigation systems may need adjustment to insure all of the lawn is being watered equally. Make adjustments if needed.
Infrequent deep watering is better than multiple light watering as this encourages deep root growth and makes the lawn less susceptible to drying out. We have no control over the natural rain fall, so use irrigation in combination with what Mother Nature provides, watch the weather, monitor rain fall amounts and add water as needed.
If you need to apply water, water early in the day to avoid excessive moisture staying on the grass blades, damp grass encourages the growth of fungal diseases on your lawn. Evening and night watering should be avoided if possible as grass blades will remain wet for a long time, if there is no other option, some water is better than none, but be aware and monitor for disease.
If you do not wish to water your lawn or if your lawn is not receiving enough water and it goes brown and dormant, no amount of water during hot weather will bring it back to life! At that point you are best to stay off the dry brittle grass to avoid damage to the plants. When the weather becomes cool and moist again, your grass should recover.
Raise your mower blades in anticipation of hot weather. Taller grass provides shade to the soil helping to suppress weeds and retain moisture. Mow regularly, remove no more than 1/3 of the grass blade, this reduces stress on the grass and reduces the size of clippings which will help them break down quicker and the mulched clippings will help your soil retain moisture.
Sharpen your mower blades! Grass should be cut, not shredded. Tearing causes stress to the grass blades, increasing water loss and disease susceptibility.
Mow in the morning or in the evening. Mowing during the heat of the day increases water usage and stress.
New Hampshire soils are naturally acidic; grasses prefer a soil pH nearer to 7, or neutral, in the 6-6.5 range.
Soil pH, whether too low or too high, impacts the grass plants ability to take up nutrients from the soil. Low soil pH can be corrected with applications of lime. As lime requires time to react with the soil, spring and fall applications generally produce the best results. The only true way to determine your soil’s fertility and pH is with a soil test. Avoid fertilizing your lawn during the hot dry summer or if the grass is dormant. Nutrients put down on plants that cannot use them may burn the lawn and nutrients not absorbed by the lawn may “run off” causing an environmental hazard.
Control Weeds, Disease and Insects:
Proper care of your grass plants will reduce weed, disease and insect pressure. Strong healthy grasses are more resistant to all pest attacks. Monitor your lawn for weeds, insects and diseases, early detection will allow for quicker control and reduce spread.
If needed, apply post –emergent broadleaf weed control before weeds go to seed, use a product that controls broadleaf weeds without damaging grass. Avoid applying weed control to stressed, thirsty lawns, as grass damage may result under these conditions.
Weather conditions will determine what insects and diseases to keep a look out for. Hot dry weather will increase the risk of Chinch Bug and Grasshopper damage, apply insecticides only if necessary and follow all label directions. Grub control should be applied during mid-summer “when beetles fly, then apply”, these products are designed to break the beetle – grub lifecycle by eliminating next year’s adult beetle crop.
Cool wet weather or watering in the evening will increase the risk of fungal diseases like Powdery Mildew, and Brown Patch. Timely applications of fungicide will reduce the damage caused by these diseases.
Re-Seeding and repair:
Because of the nature of cool season grasses, it is best to re-seed and repair lawns in the fall. Later summer and early fall soil temperatures are high enough to promote seed germination, rainfall generally increases in the fall which reduces the risk of seedling death due to drying out and the cooler weather allows the grass to grow and become established before the cold and snow arrives again.