Over watered lawns frequently lead to excess blade growth, summer fungal diseases and more frequent mowing. Excessive watering of lawns also wastes water and increases the risk of fertilizer and pesticide run-off from the lawn to paved surfaces. This could negatively impact local water quality.

Lawns that receive little to no water from irrigation or rainfall during summer months will go dormant. Grass blade coloring will lighten. Most lawns will recover when water returns. During a severe drought, the grass may die and require over seeding in the fall. This may be acceptable to those looking to conserve water during summer months.

Tall fescue when properly managed develops a deep root system and can be very drought tolerant. However, this advantage is lost if grown on shallow or extremely compacted soils.

Kentucky bluegrass can survive extended drought periods by gradually slowing growth, turning straw colored and entering summer dormancy. Once water becomes available again, it can initiate new growth from the crown of each plant.

Perennial ryegrasses have little tolerance to dry conditions and usually do not persist well in non-irrigated areas.

Fine fescues such as creeping red, chewings fescue, and hard fescue tolerate dry periods quite well due to their low water requirements.

Warm season grasses such as bermudagrass, zoysiagrass and St. Augustinegrass actually prefer warm conditions and can tolerate most drought conditions due to their deep and extensive root systems.

Water composes from 75 to 85% of the weight of a healthy grass plant. It is essential for seed germination, tissue formation, plant cooling, food manufacture, nutrient absorption and transport. Water loss from a grass plant is greatest under conditions of high light intensity, high temperature, low relative humidity, and windy conditions. Without adequate water, the grass plant can't cool itself and becomes susceptible to wilting, desiccation and death.

Morning is best for two reasons. When you water in the middle of the day, you will waste a lot of water because of evaporation. When you water in the evening, your grass could grow fungus and turn brown. Most people set their timers for some time between 4 a.m. and 8 a.m.

How Often

Automatic sprinklers have led many to believe that grass likes a regular, consistent watering schedule. You’ll conserve a lot of water and make your lawn more resilient if you try to water your lawn when it needs water instead of automatically.

The deeper the roots of your lawn, the less you will need to water. Unfortunately, most homeowners have their sprinklers set to water 15-20 minutes every other day, which encourages shallow and weak root growth. Watering deep will encourage the roots to follow the water and grow deeper.

Watering 
It's best to water in early morning, very early, like 5 a.m. This gives the lawn an opportunity to dry before nightfall, a time when many types of fungus are most active. This is also usually a non-peak time for most communities' water supply. It's also much better to water early only a couple of times a week than to water lightly more often. Deep soaking encourages deep root growth, whereas light watering encourages the roots to stay close to the surface of the soil, making your lawn more susceptible to heat and drought.

Another thing to keep in mind is that an actively growing lawn this time of year will require about 1 to 1.5 inches of water per week. This of course will depend on your soil type.  Lawns can be a source of pride — just don't let the summer heat get the most of it, and you.

Summer Lawn Care Tips

Mowing height adjustment is probably the most important practice to prepare lawns for hot weather. Mow at heights around three inches or slightly higher. If in doubt, set the mower as high as it will go. Lawns maintained at higher heights usually develop deeper roots and dry out slower than closely mowed turf. Lawn growth will slow as the weather gets drier and hotter.

Questions also arise concerning lawn watering practices for the summer. Most lawns in our area consist of cool-season lawn grasses such as Kentucky bluegrass, perennial ryegrass, and fine fescue. These grasses naturally slow down and may go dormant in the heat of summer. Decide to water lawns all summer as needed to keep them green or let lawns go dormant. Do not allow lawns to turn brown and then water them back to a green condition, as this depletes energy reserves and stresses the plant.

Water lawns deeply and infrequently, applying about 1 to 1-1/2 inches per application, depending on site variables. Water early in the day if at all possible.

Water should soak down into the soil. If allowed to go dormant, lawns only need about 1/4 to 1/2 inch of water every 2 to 3 weeks to keep root and crown tissue alive. Once more favorable cooler and drier weather returns, the lawn should break dormancy and green-up again.

It's best to hold off until later in the season for most other lawn care practices, including fertilizing, seeding, thatch control, and applying weed killers. The period from late August through early September is ideal for many of these practices. For now, help your lawn by proper mowing, watering, and keeping foot and vehicle traffic off the grass as much as possible during the heat of the summer months.