Water deeply but not often.
Your lawn should receive 1/3 an inch of water every other day in order to remain strong and drought-resistant. Water in the morning to avoid the afternoon's high evaporation rates and the possible fungus risks your lawn could face if irrigated at night. Shoot for 6-10 am.
A 2-3 inches layer of mulch makes a huge difference in hot weather. It acts as a shade cloth to hold in moisture and cool plant roots. Without mulching, the intense heat from the sun can make your soil dry — and you end up watering the garden even more.
Don't water everyday.
The more shallow your grass roots are, the less hearty it will be in hot weather. Instead water about two times per week for longer periods of time. The local lawn companies I have spoke with around my area (North Central Texas) recommend about 20-30 minutes per watering cycle twice a week.
Water Wisely
Most lawns need to be watered no more than three days a week in the spring as well as in the summer and two days a week in the fall. This watering schedule is recommended under normal water supply conditions.
Avoid watering grass on a hot afternoon when it's 95 degrees or higher. The best time to water grass is at dawn or in the early evening. Water deeply three times a week instead of a little water daily. Test whether your sprinkler system is watering your lawn evenly.
It is ideal to water lawns about one inch of water per week. To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water.
It is often recommended that you water your lawn early in the morning, as early as 4 am and no later than 10 am. During extreme heat, watering should be done no later than 7 am.
Typically, most lawn irrigation periods during the summer should last between 25–30 minutes each. This amount of time depends on a lot of different factors though. As previously stated, each irrigation system or sprinkler can deliver different amounts of water and it's important to hit that 1 inch per week requirement.
In times of extreme heat, it is vital to water your lawn for about 30 to 45 minutes daily. Once the temperatures drop below ninety, you can cut back to watering three to four times a week, until that blissful thunderstorm comes and quenches your lawn's thirst!
Topdress Your Lawn.
The #1 thing you can do to improve the water holding capacity of your turf is to amend the hard clay and rock soil that most of us inherited with a 3/8ths to 1/2 inch layer of topdressing. Topdressing will: (1) Act like a sponge and allow your turf to hold more water before run off.
By aerating the area you'll de-compact the soils which will help nutrients and water to penetrate the soil. Aeration is much easier after a good soak, so if your lawn is already dry, don't try to aerate before the soil is softened up with deep watering. Wetting agents assist water to absorb into the soil.
So, how often should you water your lawn in the summer? The answer may surprise you. Between irrigation and natural rainfall, your grass should receive between 1 and 1.5 inches of water each week during the summer. Water deeply every other day for the best results.
If it's 70-80 degrees outside try watering 2-3 times a week. During the spring your lawn will be fairly easy to manage so you don't have to water all the time. In the blazing summer, when temperatures are between 90-100+, try watering 3-4 times a week.
During extremely hot weather (daytime temperatures above 90F and nighttime temperatures above 70F), try to water daily or every other day. In a 10x10-foot garden, this would mean giving your plants 8 to 9 gallons of water each day.
In general during hot summer months, you should be watering your lawn up to three times per week if there wasn't any recent rainfall. As a general rule of thumb, watering up to one inch deep each time you water your lawn is ideal.
Watering in the morning (before 10 a.m.) is the best time for your lawn; it's cooler and winds tend to be calmer so water can soak into the soil and be absorbed by the grass roots before it can evaporate.
If you can water, do so deeply but infrequently. When the water penetrates further into the ground, it's slower to evaporate and encourages deeper root growth, which it turns helps protect the grass during the next heat wave.
1) Watering for Too Long
This should be no more than three times per week. Set a timer for 20 minutes and stick to your schedule, even if you think the lawn needs more water. You don't want to oversoak it.
It's important to water deeply and infrequently to encourage deep root growth and drought tolerance. Most grasses require about 1-2 inches of water per week, which can be achieved through one or two deep watering sessions. Overwatering can lead to shallow root growth, disease, and pest problems.
Watering every day is not advised. It should be done 2 to 3 times per week only to prevent a shallow root system. If possible, water during the early morning hours to ensure that the lawn dries entirely before nightfall. However, watering at any time of the day is better than not watering at all.