The Dirt Gardener's Column for June 26

Q. When and for how long should I water my lawn? I’ve been reading that you promote a deep-rooted grass by watering infrequently but for twenty minutes to a half hour. My husband says he waters daily for ten minutes starting at six am. Who is right?

A. This is a tricky question, as both answers could be correct. The key factor in determining the correct answer is found in the soil profile. This is where the majority of the roots are found. With a round nose shovel, I’d make two perpendicular cuts in the turf. At the apex of the two cuts, lift the pie like section up exposing the profile. You should now clearly see the blades of grass, thatch, an organic layer between the grass and the soil along with the native soil. Your two options are ‘A’, an infrequent watering schedule but for a longer period while ‘B’ has you watering frequently for a shorter period. For example, with Option ‘A’ you would be watering every five to seven days verses Option ‘B’ everyday. For Option ‘A’ to be viable, you need to see roots in the native soil layer. The lack of roots indicates you have a shallow rooted grass that requires frequent watering to sustain them during the summer months. The grass roots have no ability to access the moisture in the native soil so water stress occurs quickly. Option ‘B’ would then be the appropriate answer. Over the years, this has been an increasing problem with the popularity of soded lawns. It was less of an issue with lawns started from seed as the roots penetrated the native soil right away. Watering longer but less frequently is not going solve the problem in any turf the receive six hours or more of direct sun per day. Aerating, removing the cores and then top-dressing the area is one method of encouraging the shallow roots to go down. This should be done twice a year for several years. Another method is with Liquid Thrive from Soil Logic, a liquid soil conditioner. Liquid Thrive is designed to break up clay soil, improve drainage and reduce compaction. Neither of these methods are quick fixes. They take more than one season to be successful; however, they’re less expensive than starting over by installing a new lawn. I prefer watering turf and landscape plants during the morning hours from four to eleven am. Your applying water on a rising temperature putting moisture in the root zone as the plants needs it and the air is calm unlike in the afternoon and evening hours. With Option ‘A’, Drought Defense from Soil Logic can also extend the days between watering. Drought Defense changes the physical nature of the water droplets along with changing a soil’s ability to absorb and hold moistue. When applied to the soil surface and watered in, it adheres to the soil particles where it will stay for many weeks. The captured water molecule is no longer able to evaporate, allowing moisture in the root zone to stay longer. Hence you’re able to water les often.

by Buzz Bertolero, CCNP