Summer is the time when your lawn actually needs more water than any other season. It is necessary for the survival of cool-season grasses and to support the growth of warm-season grasses.
But the question is, how often to water the lawn in summer? Is there a recommended frequency?
Unfortunately, there is no direct answer. You can't set a frequency without considering the sprinkler rate, duration of watering, type of grass, and soil condition. You have to consider all these factors to provide an adequate amount of water for your lawn.
Let's understand how to decide the right frequency and watering duration by considering different factors.
Deep vs Shallow Watering
Shallow watering is not recommended in summer. If you are turning on your sprinklers for 5-10 minutes daily, it's not enough for the lawn.
The reason is that the soil is extremely hot. When you water the lawn, the water evaporates quickly due to extreme temperatures. It does not reach the depth of the soil where it's needed. The water remains at the top and evaporates in no time. After that, your lawn suffers from water deficiency.
Secondly, due to shallow watering on a regular basis, you train the roots to stay at the top of the soil. That's the only place for them to absorb water. But when you miss a watering session or the soil dries, the sun bakes the root at the surface, which leads to the browning of the grass.
Deep watering is the way to go in summer. You provide a significant amount of water in a single session. It keeps the soil moist for a longer period. Even if some of the water evaporates, the rest is available to the grass. Generally, lawn owners should aim for 1-1.5 inches of water per week.
In deep watering, the water penetrates the soil and goes deep about 6 to 8 inches. The grass roots chase the water downward and create a deep root structure. Thus, the grass can absorb water from the depth. Secondly, the water that has penetrated deep into the soil will not evaporate quickly. It will remain in the soil to quench the thirst of the grass.
The Right Frequency
We have established that deep watering is the right way to water grass in the summer. Now, let's figure out the frequency.
Ideally, you should split the total amount of water you need to provide to the grass into 2-3 deep watering sessions.
Suppose you want to provide 1 inch of water to the grass throughout the week. You can provide that in two sessions, which means 0.5 inch of water in each, one on Saturday and the second on Wednesday.
Watering 2-3 times a week is better than daily shallow watering. This is a general rule for watering grass in summer, but it can change because of some factors. Let's understand them.
Factors that Affect How Long/Often to Water Grass
Considering these factors is essential to figure out the best frequency and duration for lawn watering.
Soil Composition
Suppose your lawn soil contains too much sand. In this case, when you water the lawn, the soil does not retain water. Sand particles aren't close together; there are huge gaps. That's the reason the water drains quickly. Therefore, the roots have minimal time to absorb water. No matter how deeply you water the lawn, the grass won't be able to absorb enough water.
Sandy soils should be watered more often with less volume per session, as the soil can't hold water. For instance, if you want to water the lawn for 30 minutes, you can do it three times for 10 minutes each.
Contrary to that, some lawn soils have too much clay. It holds water for very long, more than the required time. It prevents runoff, but if the soil stays moist for too long, it could suffocate the grass and lead to root rotting. The worst part is that the water stays on the soil and is not absorbed by the roots.
For clay soil, the Cycle and Soak method is excellent. It works well even if the soil is compact or the lawn is sloped. In this method, you need to water the lawn first for 15-20 minutes. It softens the soil. After waiting for 30 minutes, water for another 20 minutes. Now, this water will easily reach the root zone.
Loamy soil has the perfect balance; it neither drains water quickly nor retains it for too long. And this is what every lawn needs. You can follow the normal watering routine, which is 2-3 times deep watering per week.
You can improve the lawn soil by adding organic compost and make it perfect for the grass. But if you don't want to do that at this stage, you can adjust the watering habits.
Climate
Watering should be adjusted according to the climate.
In arid and semi-arid climates, like Arizona and Nevada, lawn owners need to water a bit more. That's because the evaporation rate is high, and more water is needed to fulfill the needs of the grass. Instead of 1 inch of water, they can aim for 1.5 to 2 inches of water per week. It can be split into 3-4 watering sessions.
For humid regions and the Gulf Coast, lawn owners should water twice a week in the early morning. If there is rain expected, do not water the lawn. Sometimes, the rain is enough to cover the watering needs of the whole week. It's necessary to keep an eye on the weather forecast.
In high-wind climates, the transpiration rate is high. Which means plants sweat more moisture through leaves, and then the water evaporates from the surface. It silently steals water from the grass. Therefore, lawn owners can add one more deep watering session to handle the moisture loss.
Transitional areas are quite tricky. They experience dry summers, cool winds, wet springs, and almost everything. Therefore, lawn owners need to be more careful. They have to adjust the watering routine accordingly. Water more if the weather is too hot, and reduce watering if there is rain predicted during the week.
In moderate summer regions, 1-1.5 inches of water per week is enough. However, lawn owners can adjust watering according to the daytime temperature, wind, and rain.
Grass Type
Cool-season Grasses
Cool-season grasses follow the C3 photosynthesis pathway, which begins to fail when the temperature increases. Initially, the plant starts to burn its stored energy to survive, which is called photorespiration. Then, it enters partial dormancy when the temperature reaches 85⁰F during the summer.
The grass is in the survival stage; it spends its energy to bear the harsh temperature instead of growing. Secondly, it has higher transpiration rates, so it sweats water faster. Simply put, it needs more water than usual.
You should provide cool-season grasses with 1.5 inches of water per week. Split it into three deep watering sessions.
Warm-season Grasses
Warm-season grasses grow actively in summer. They use the C4 photosynthetic pathway, which works well in high temperatures between 80⁰F to 90⁰F.
These grasses can handle drought and extreme temperatures. They have a deeper root system to absorb water from depth. Secondly, they can prevent water loss by closing their pores, which is why they do not lose excessive water through transpiration.
You can water warm-season grasses deeply during the summer season. 1 inch of water per week is enough to support their aggressive growth. You can split it into two watering sessions.
Further reading: Cool-season grass vs Warm-season Grass
Lawn Conditions
Certain lawn conditions might change watering routines a bit.
Compact Soil: When the soil is compact, it does not allow water to go through. The water remains at the top of the soil and doesn't reach the roots. The tiny soil particles are so close that there is no air pocket left for air or water passage. You should think about lawn aeration as soon as possible. Till then, you can go with the Cycle and Soak method for watering.
Thick Thatch: It is the layer of organic matter above the soil. When it is more than 0.5 inches, it acts like a sponge. It absorbs all the water rather than passing it to the soil and roots. It reduces the water efficiency. You should do dethatching to remove the thatch layer. But if you haven't done so yet, increase the quantity of water in each session.
Shaded Areas: If there is any shaded area in the lawn, it will be less affected by the heat and direct sunlight. The water will stay longer in the soil. Therefore, you can reduce the watering quantity a bit. Too much water can actually invite fungus.
Sloped Areas: The grass in sloped areas can't absorb water, as it runs off easily. Therefore, frequent and shallow watering sessions are recommended. You can also go with the Cycle and Soak method.
Newly Seeded Lawn: After you overseed or reseed a lawn, you need to keep the soil moist. Seeds require consistent moisture for germination. Even one dry spell could kill them, and after that, you can't do anything. They require shallow and frequent watering. You can water 1-2 times a day for a few weeks until the grass blades are out of the soil and are about 1 inch. For more details, check out how long to water new grass seed.
Measuring the Amount of Water from the Sprinkler
We have mentioned multiple times in the article to provide 1 inch or 1.5 inches of water to your lawn. But how can you measure this amount while using sprinklers?
Step 1: Place a few empty tuna cans in your lawn.
Step 2: Run your water sprinkler system for 15 minutes.
Step 3: Measure the depth of collected water in all tuna cans and take the average.
Step 4: Suppose you measure 0.25 inches in the tuna cans. Now, you can easily calculate the sprinkler rate. In this case, the sprinkler rate is 1 inch per hour. You can also use the following formula.
Sprinkler Output (in/hr) = [Depth of water in cans (inches) × 60] / Time (Minutes)
Sprinkler Output (in/hr) = (0.25 x 60)/15
Sprinkler Output (in/hr) = 1 inch per hour
Once you know the sprinkler rate, you can easily figure out the duration for watering. Suppose you want to provide 1.5 inches of water to the lawn, and the sprinkler output is 1 in/hr. It means you need to keep the sprinkler system running for 1.5 hours or 90 minutes. If you want to split it into two watering sessions, each session should be around 45 minutes.
When is the Best Time to Water Lawn in Summer
The time of watering is equally important as the frequency and amount of water. Watering at the wrong time results in wastage and lawn diseases.
The best time to water a lawn in summer or any season is early morning. The optimal window is 5 am to 10 am. In extremely hot regions, you can do it a bit earlier, such as 4 am to 9 am.
The reason for selecting this time is the low evaporation. It's the coolest part of the day, and the sun is slowly rising. Thus, the water stays in the lawn and is available to the roots. The wind is also calm, so if you turn on the sprinkler system, it won't be disturbed.
Another important reason is that the grass has enough time to absorb the water. After that, the sun will rise and dry out the grass blades. Which means the soil won't stay damp for a longer period. It reduces the chances of fungal diseases.
The worst time is midday. The sun evaporates water at a high rate, so the soil dries out quickly. The water won't reach the roots; it's wasted.
You might think about watering at night. But it is not recommended. It is definitely the coolest time, but if you water at night, the soil will stay moist for too long. It will create a favorable environment for fungal diseases.
How to Achieve Maximum Efficiency
Automated Water System
Instead of counting every minute and waiting to turn off the sprinkler system, go for automation. You can install a simple smart switch. With this, you can control the watering duration and control it from anywhere. It saves you time and water.
Smart Irrigation
Smart irrigation includes weather-based controllers that keep an eye on the weather forecast and adjust watering according to the conditions. For instance, if there is rain, it will automatically reduce the watering duration. Thus, once you install a smart irrigation system, you don't have to worry about adequate watering. It will take care of your lawn.
Mowing Height
Mowing also plays an important role in reducing the effect of summer heat. Make sure to keep your grass at the optimal height during the season.
Keep cool-season grasses around 3.5 to 4 inches. These grasses are in survival mode, and they can't bear extreme heat. When you keep them a bit higher than usual, they provide shade to the soil. It keeps the area a bit cooler and retains water for a longer period. It also keeps the crown safe, where all the energy is stored. And don't let it overgrow, as it can invite mold.
Warm-season grasses love the heat and high temperatures. They grow aggressively in summer, so you can keep them around 2 to 3 inches. You can also go lower with some grass varieties, but maintaining this height is the safest.
Now, the real problem with most lawn owners is that they don't have enough time to mow the lawn. Their busy schedule and mower issues keep them from maintaining a perfectly cut yard.
A robot lawn mower is the perfect solution for them. It automates lawn mowing and saves time and money. Once you set the time and mowing height, it does everything on its own. You have a perfectly manicured lawn every day, which not only looks aesthetic but also keeps the grass healthy.
For small lawns up to 0.25 acres, the Navimow i2 AWD series is excellent. If you have a medium lawn up to 0.5 acres, the Navimow H2 series is perfect. For large lawns, you can go with the Navimow X4 series.
Final Words
To determine the perfect watering frequency for your lawn in summer, you have to consider the grass type, climate, soil composition, sprinkler rate, soil compaction, slope, and various other factors. There is no fixed value, as all these factors have some effect on the lawn. We have explained all these variables to help you decide the frequency and watering duration without any hassle.
In most cases, you should provide 1-1.5 inches of water per week and split it into two watering sessions. In arid climates, you can water up to 3-4 times per week. For adequate watering, calculate your sprinkler rate and create a watering routine. You can achieve better results with smart irrigation and by keeping the grass height a bit higher than usual.
