There are a few things you can do to help your existing lawn before you have to add water. The first cultural practice worth noting is mowing to a height of 3-3.5″, especially in full sun. Mow only if you need to and do so in the am or late pm, try to avoid 12pm to 3pm when the sun is the highest and the grass is the most stressed. Mowing during this time frame, especially in high heat (85 or above)- combined with dry conditions or turf that is already stressed will most likely cause more browning and or leave mower tracks. Imagine the stress placed on a lawn that is already just holding on with dry, sandy soil. Imagine then the additional moisture loss out of each leaf blade as you mow, the result can be quick and dramatic, browning within hours or days at best. Once your lawn has shut off, either in patches or entire areas- it will take days if not weeks of solid irrigation to “restart” the growing process. As I have said before, browning is a survival mechanism when your turf shuts off from growing due to a lack of moisture in the soil. If there is not enough moisture, turf growth will slow down and finally stop. During this process, your lawn will turn a dull, purple blue- to possibly white spots on the leaf blade- and finally to a tan or complete brown.
Providing irrigation at the earlier stages will produce faster results than the later brown, the time frame can be from a few hours or overnight with light stress (hazy or dull green/blue) to weeks with all on dormancy and browning. So what is a good rule of thumb when it comes to irrigation? That is a complicated question so I will stick with the average home- without an irrigation system. If you want a green lawn during the summer- you will have to irrigate at some point or prepare to see browning to varying degrees as rainfall comes and goes. There are a few types of irrigation goals, one is to keep the lawn aesthetically pleasing and green. The second would be to keep your lawn alive during an extending dry period- such as 3 to 4 weeks with an inch or less total. Most lawns will require 1″ of rain per week to grow properly without experiencing drought. Remember, grass blades are mostly water so to expect your lawn to grow and or stay a vibrant green in high heat and or lack of rain is simply not realistic. Preparing your grass with slow release fertilizers, high calcium lime, sea kelp, and aeration are powerful tools which keeps your grass healthy. Healthy turf will respond faster to irrigation, recover better, and withstand dry conditions- especially if mown correctly (3-3.5″).
Watering your lawn for aesthetics is best if you can proactively watch for dull patches- if you do see one, hit it with water for 1/2hr to 1hr for a day or two. You should see recovery fairly quickly if your turf is in good shape. Most lawns have “hot spots” or zones which tend to dry out faster than the majority of your lawn. If you know where these areas are, you can simply watch them and be prepared to water them more often than the rest of the lawn. In some cases, those may be the only sections you water, so have your hose and sprinkler ready. Don’t waste your water, don’t irrigate for hours upon hours, after an hour or so- you have provided enough and soaked the upper root zone.
A general rule on watering- some water is better than none. As a rule, watering in the early am to late am is the best time. Watering at high noon or the afternoon will not burn your lawn, but a lot of water will evaporate- a waste of resources for sure. If you cannot water until the afternoon to early evening- you are likely to set up your lawn to summer diseases like brown patch or red thread. As a rule, keeping your lawn dry going into the night is your best option. Again, diseases like brown patch are enhanced by high heat, humidity levels, and excessive soluble nitrogen (liquid fertilizer). A light touch is often required in late to mid July to August if the heat and humidity arrives.
Survival irrigation are for those of you who have sections of lawn that “suddenly” turned brown. You wake up one saturday morning and go outside to get your newspaper- you glance up and parts of your lawn are brown! When did that happen? Well, likely it has been going down hill for a week or more and you just noticed the color change. This is certainly not magic! What can you do? Why bother? Well, if your grass is toast, a nice light brown like I enjoy my coffee- any water will help- believe me. At this stage, your grass is close to dormant or dormant. Don’t mow it and add more stress. Any water will help keep the crown- the heart and soul of your lawn alive. While most growing lawns need 1″ per week of rainfall, even if you water once for an hour or so, each week- you can keep your grass in a dormant state but alive. What you don’t want to do is water vigorously for one week each day and then just let it ride for the rest of the month. This kind of irrigation is survival irrigation, minimizing death and future dead patches. Speaking of dead patches- this is a dangerous time for your lawn because you will never see damage inflicted by chinch bugs, cutworms, sod webworms, or grubs. September rolls around and you chalk up dead areas to lack of water when in fact you had and still may have insect activity.
Irrigation does not have to make you a slave to your lawn if you know what you want to accomplish and how your lawn reacts to heat and dry weather. Break out those hoses and check your sprinklers today!