Knowing how to water a lawn the right way is critical to the overall health of your lawn. The frequency and amount of water you apply to grass vary, depending on soil, time of year, weather conditions, type of grass, and so on. Follow these tips when watering, and your lawn will shine:
Water to the proper depth: Moisture should penetrate to about 6 to 8 inches deep. Watering less deeply results in a shallow-rooted lawn that dries out quickly.
On the other hand, applying water that penetrates much deeper than 6 to 8 inches is wasteful because most grass roots don’t grow longer than that.
Check how deeply the water penetrates your lawn by probing the ground with a stiff metal rod or long screwdriver. The rod moves easily through wet soil and then stops, or becomes difficult to push, when it reaches dry soil.
Allow the lawn to partially dry out between watering: This step creates the good moisture-air relationship that is essential for healthy roots. The lawn shows you when it’s getting dry and needs water: When you walk on the grass, you can look back and see your footprints. The grass also changes color from bright green to a dull, almost smoky, grayish blue when it is dry.
Avoid runoff: If you apply water faster than the lawn can absorb it, which happens with many types of sprinklers, the water runs off into street gutters and into oblivion. That’s wasteful, so don’t do that. Instead, water in short intervals of about 10 to 15 minutes, turn off the water (or move the sprinkler) to let the water soak in, and then turn the sprinkler back on for another 10 to 15 minutes. Repeat this procedure until you get the water down to about 6 to 8 inches deep.
You can avoid runoff in other ways. One is to use sprinklers that apply water very slowly The other method is to get rid of thatch, a layer of organic crud that builds up near the surface of a lawn and dramatically slows water penetration.
Water in the morning: Early morning is the best time to water. The weather is usually cool and calm, humidity is usually high, and water evaporates less. The wind also doesn’t blow the water into the neighbor’s yard. Morning watering gives the lawn a chance to dry off before evening, which can protect your lawn from disease and pests.
In midsummer, most lawns need between 1 and 2 inches of water a week: You can apply the whole amount of water once a week, but most people get better results by splitting it into two applications. In sandy soils where the water penetrates quickly, splitting the water into three applications may work better. Watering more frequently than three times a week is verboten.
Watch your lawn and make appropriate adjustments: If the lawn doesn’t seem to dry out between waterings, stretch the intervals in between. If the water doesn’t get deep enough, apply a little more at each watering, but water less often. If everything seems fine, try cutting back on the amount you apply anyway and see what happens. Maybe you can conserve some of that valuable resource.
Watering newly planted lawns is a whole different ball of wax. You need to water new lawns more often until the grass plants become established.