During hot, dry weather, folks envision their lawns turning into dusty prairies, complete with forlorn tumbleweeds rolling by and someone playing a harmonica in the background. However, overwatering does more damage, so you’re better off erring on the dry side. If your lawn has a bluish-green tinge or your feet leave imprints in the turf, it could probably use a drink.
The best time to water is between 4 a.m. and 8 a.m., arguably the most opportune time for an automatic irrigation system to switch on and spritz paper carriers, early-morning joggers or neighbors leaving for work with their hair gel just so. The second-best time is between 8 p.m. and midnight. Most sprinklers should be left in one place for two to three hours in order to thoroughly wet the root zone. And, of course, most sprinklers are conveniently designed to also soak sidewalks, windows, patios and parked cars with open sunroofs. When a lawn is not watered during a drought and it starts turning brown, it’s not dead, but dormant. When moisture returns, either through rainfall or irrigation, it will likely revive itself.
You can find some good information about watering the lawn in Purdue publication AY-7, “Irrigation Practices for Homelawns,” available at www.agry.purdue.edu/turf.
A sprinkler or sprinkler system can also be used to water flowers and vegetables, but you run the risk of creating other problems. Water early in the day and the plants dry quickly enough to head off wet-foliage woes like powdery mildew and other fungal diseases. These diseases are nasty in and of themselves, but they also leave plants more vulnerable to pests like the squash vine borer. If you can’t water early in the day, consider a soaker hose or drip irrigation system. Both of these send the water directly into the soil where it’s needed. I’ve never tried a drip irrigation system, but a soaker hose is a relatively inexpensive and easy solution. That is, it’s easy once you get the hose uncoiled and placed where you want it.
As a general rule, flowers and vegetables need an inch to an inch and a half of water per week, perhaps more during hot and dry periods. To measure Mother Nature’s contribution, I keep at least a couple of rain gauges around the garden (one readable from the kitchen window) and empty them every Sunday.
If the soil feels dry about an inch below the surface, you probably need to water, especially if plants are wilting. However, if plants are wilting and the soil is moist, root rot from overwatering is likely preventing the plant from absorbing water. Other signs of overwatering include yellowing leaves, especially near the bottom of the plant; powdery mildew or gray mold; green algae on the soil surface and soft or mushy stems.
Overall, watering deeply and infrequently is best, but some plants prefer to have their soil kept consistently moist. As always, read the seed packets and plant tags. Plants are naturally inclined toward balance; all we need to do is help them keep it.