It is always nice to have a long soaking rain in midsummer to make a lawn plush and green. But too much rain from a summer storm can make a lawn white, red, yellow, and brown. Some homeowners who are knee-deep in floodwater say, "Enough, already!"
Mike Reynolds of Black Diamond Garden Center says waterlogged turf can die after being submerged for days. "It takes about 72 hours for turf to die underwater," he says. "It may die even quicker in this kind of heat because there is no way for the plant to exchange gases underwater. It essentially drowns."
At this time last year, Mr. Reynolds says, we were fighting a drought. "Many lawns were brown already." Light summer rainfall caused many lawns to go into summer dormancy by July, leaving many homeowners with a crusty brown carpet of turf. He says, "This year we have above average rainfall and many of those lawns are still lush and green."
But all of this hot, moist weather may cause white fungus and red rust to grow on turf, requiring application of a fungicide. Mr. Reynolds says fungus has been a problem in wet areas that haven't had a chance to dry out. "I have had to spray a lot more fungicide this year already," he says. Last year, he says many lawns struggled against insect damage as well as a lack of rain.
The problem of heavy rains causing low areas to flood is common in farmers' fields, residential areas - even those that are fitted with drainage tile - and on golf courses. "Some fairways that stay underwater for more than three days will suffer," Mr. Reynolds says. "That's why turf managers spend so much time on getting their drainage right."
To try to rescue your turf, you have to find a way to drain it. Some possibilities:
●Cut a small trench to a natural drainage area in the lawn.
●Direct water to a downspout tile that reroutes water falling from the roof and takes it to the street.
●Dig a trench to a nearby ditch or hook up a pump to move the water to lower ground.
There's not much you can do for lawns that have been submerged for more than 72 hours. When turf starts to die, it turns a sickly shade of yellow, then dries up and turns brown. If that happens, Mr. Reynolds says to let the turf dry, then replant the damaged areas in September when the weather is cooler.
For the best chance of regrowth, rake out and remove the old sod. Sprinkle a light layer of grass seed on the bare spots, then top dress the patches with fresh topsoil. Keep the patches moist until the new grass starts to sprout. Then water the areas once to twice a week.
"I don't see this flood period causing any long-term disease problems," Mr. Reynolds says. "The turf will bounce back if it hasn't been underwater for more than three days. It always does."
He adds, "I would take this kind of rain over a drought anytime."