You must water your lawn in hot weather at least three times per week, as long as you soak the soil to a depth of at least 6 to 8 inches. Akin to normal conditions, watering your lawn daily will create a shallow root system, which dries out fast and weakens your lawn.
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. Your turf should receive about 1/3 an inch of water every two days in order to maintain deeper roots, thus helping protect against drought.
WATERING SCHEDULE
Deep watering helps to encourage deep root growth. Deeper roots stay cooler and stronger to better protect your lawn and garden from heat stress. Allow a deep watering at least once per week, twice if the temperature exceeds 100 degrees or more for several days in a row.
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.
It is ideal for watering your lawn about 1 inch of water for every single application per week. On average, it takes 30 minutes to disperse 0.5 inches of water. Therefore, you must water your lawn in hot weather three times per week, for about 30 minutes each, to get an inch of water on your lawn.
Vegetables and fruits that are developing fruit during a heat spell need regular watering to ensure good production. Vegetables typically require daily watering during summer weather, but may need a second watering when temperatures are extremely high.
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.
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.
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.
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.
If your grass gets too much water, it doesn't get oxygen and can actually suffocate. Too much water also makes your grass more susceptible to disease.
In conditions when the heat is just too much for your grass to overcome, it will essentially shut down until cool, moist weather returns. During this condition, you should irrigate your lawn at least once per week. If you have a newly-planted lawn, don't let it go dormant.
Grass needs the benefit of the day to dry and heal before dusk settles. Since mowing your grass in the early morning can damage it and mowing it during the early afternoon can burn it because of all the high temperatures, the ideal time is mid-morning. That is of course if you're free during that time of day.
During really hot weather, water your vegetables at least two to three times a week. Watering the garden deeply is critical. The water must go down, down, down to encourage deep roots and get away from the hot soil surface.
It is best to turn on your system during the warmest time of the day when anticipating freezing conditions. Be sure the outside temperature is 40 degrees fahrenheit or above when you run your system. You ABSOLUTELY do not want to run your sprinkler system during a hard freeze as this will cause damage to your system.
Soak the lawn with a sprinkler system
Ensure you soak the lawn thoroughly until you see small puddles of water on the surface. "The best way to water your grass in hot conditions is to use a sprinkler system and really soak the lawn,” agrees Jonathan McQuire, gardener.
Watering in the morning also helps your lawn stay cooler throughout the hottest parts of the day, decreasing the amount of heat stress for the turf. If you are unable to water in the mornings, early evening (between 6:00 PM and 8:00 PM) is the next best time.
Once temperatures reach 77 degrees, it becomes too hot for root growth, and root growth ceases. When temperatures reach 90 degrees, it becomes too hot for shoot growth and the grasses stop growing and begin to fall dormant, with the surface grass turning a brown hue.
Grass generally stops growing once temperatures drop to below the range of 50-55 degrees Fahrenheit or reach above 90 degrees Fahrenheit. Since soil takes longer than air to lose and retain heat, it will take a period of a least a few days for a temperature change to impact the growth of grass.
In hot weather, patients should be encouraged to drink more than 6 – 8 mugs of fluid per day.
Drinking at shorter intervals is more effective than drinking large amounts infrequently. Do not drink more than 48 oz (1½ quarts) per hour! Drinking too much water or other fluids (sports drinks, energy drinks, etc.) can cause a medical emergency because the concentration of salt in the blood becomes too low.
Water has a high specific heat capacity—it absorbs a lot of heat before it begins to get hot. You may not know how that affects you, but the specific heat of water has a huge role to play in the Earth's climate and helps determine the habitability of many places around the globe.