Paris Alston: This is GBH’s Morning Edition, and the heat goes on. We’ve got a little break from this week’s hot temperatures, but another heat wave is on the way. Earlier this week, we spoke with meteorologist Dave Epstein about how humidity can make the hot air feel worse. And now he’s here to talk about lawn care when the grass is getting scorched. So first off, how do heat and humidity affect grass?

Dave Epstein: Yeah. So, you know, a lot of us have lawns in this area. And if you do have a lawn and you want it to look good and now you’ve got heat, and sometimes we have these spells where we don’t have as much rainfall, the grass gets stressed out. It gets stressed out because [of] a lot of sun, the soil dries out, it needs moisture, and even the high humidity can start to promote some of the diseases that affect grasses. Things like dollar spot, for example, and other fungal diseases. And you can start to notice patches of it dying out.

Alston: So given that, what are the best practices for lawn care?

Epstein: Yeah. So a couple of things. Number one is: Leave your lawn a little bit longer this time of the year. So I’m looking out as you and I are talking here this morning, I’m looking out, and my lawn is probably four inches long. Most people would come on and say, hey, you need to mow it. And yeah, it is getting to that point where it needs mowing, but I keep it very long during the course of the summer, and I’ve really changed my practice over the past decade or so, because that way less moisture is leaving the lawn and the lawn tends to stay greener and it needs less water.

Alston: What about watering in general? Should you be doing that with these high temperatures?

Epstein: Yeah. So if you’re going to water, if your soil starts drying out and the lawn starts, you know, burning out — and you can water, some towns have water bans — the best time to do it is from about 4 a.m. till 7 a.m. in the morning. So the reason for that is that if you’re done by 7 or 8 o’clock, it’s not going to make a big difference. That now the moisture that is on the grass blades will dry out during the day. Also, as you’re watering, all that water is going into the lawn. If you were to water, say, at noon, 1 p.m., a lot of the water that is being released, whether it’s an irrigation system or whether it’s a sprinkler, it’s evaporating into the air even on a humid day. So you’re not getting as much. And if you water in the evening, you’re leaving your lawn wet all night long, and that can promote disease. So that’s why that early morning is the ideal time.

Alston: Now you mentioned different types of lawns and I hear there’s something like a monocultural lawn. What is that?

Epstein: Yes. So monoculture lawns kind of, you know, became avant garde, in the United States back in the '30s, '40s, '50s when, you know, you had these companies showing you pictures of a lawn that had just perfect grass. Right? All the blades look the same, all the same color, same height. And what that is, it’s just one type of grass. So I’ll pick one — it’s all Kentucky bluegrass, for example. And it does look really nice because it’s all the same thing. But the problem is, is that if you have a disease that moves through a lawn with one thing, it’s going to rip that out and it’s going to kill it. So, for example, if all of our forests were just beeches and that’s all we had, and now we have beech leaf disease moving through New England, we’d end up with no forests. So it’s important to kind of mix your lawn up with lots of different types of grasses. I have clover in my lawn, I have fescue, I have Kentucky bluegrass. I have some other grasses that I have no idea what they are, kind of just moving around. It’s not uniform in color or height, but it’s a much healthier lawn.

Alston: Okay, a little ecological diversity in a sense. Now —

Epstein: Exactly.

Alston: So is there an ideal seed mix that you would use when you’re trying to get this mélange of grass?

Epstein: Yeah, I would say the key word you use, Paris, is mix. When you buy grass seed, you want to look for a seed that has some of the blue grasses, has some of the fescue. And another thing that you can add into the mix are some of the micro clovers. So there’s some great white clover as a high-level type of plant that can be mixed into the lawn. Now, why is white clover good? It’s drought tolerant. It needs less water. It flowers, it’s good for pollinators. And it helps your soil. Also rabbits, which are all over the place this summer, love the white clover. And so they’ll also eat that on your lawn rather than your plants. They’ll choose that first.

Alston: Well, that is meteorologist Dave Epstein talking about how to care for your own lawn as we are in the middle of these high temperatures. And if you ever have a plant or weather related question for Dave, you can text that to (617) 300-2008. Dave, thank you so much.

Epstein: You’re welcome.

Alston: You're listening to GBH News.

Hot summer days can mean trouble for lawns. Heat can scorch the grass and leave it dry, and too much rain and humidity can encourage disease, said GBH’s meteorologist and gardening expert Dave Epstein.

There are things people can try to help their lawns out. Here are three key tips from Epstein.

Mow less

Cutting your lawn can leave it more vulnerable to drying out during long spells of heat. An easy way to avoid that: Let it grow out.

“My lawn is probably four inches long,” Epstein said. “Most people would come and say, ‘hey, you need to mow it.’ And yeah, it is getting to that point where it needs mowing, but I keep it very long during the course of the summer, and I’ve really changed my practice over the past decade or so, because that way less moisture is leaving the lawn and the lawn tends to stay greener and it needs less water.”

Water early in the morning

Watering the lawn during the hottest parts of the afternoon can lead to too much evaporation, meaning the grass won’t get enough water. And watering it at night can leave it too wet for too long, which can encourage fungal diseases, like dollar spot.

The sweet spot is usually between 4 a.m. and 7 or 8 a.m., Epstein said.

“The moisture that is on the grass blades will dry out during the day,” he said. “Also, as you’re watering, all that water is going into the lawn.”

Reject the monoculture, embrace ecological diversity

Monoculture lawns — large swaths of ground covered with only one type of grass — became popular in the U.S. in the 1930s, ’40s, and ’50s, as companies pushed advertisements with perfectly uniform lawns.

“It does look really nice because it’s all the same thing,” Epstein said. “But the problem is, is that if you have a disease that moves through a lawn with one thing, it’s going to rip that out and it’s going to kill it.”

Epstein recommends mixing lawns with different types of grasses and small plants.

“I have clover in my lawn, I have fescue, I have Kentucky bluegrass. I have some other grasses that I have no idea what they are, kind of just moving around,” he said. “It’s not uniform in color or height, but it’s a much healthier lawn.”

He recommended looking beyond just grass seeds. In the past, he’s suggested creeping thyme, ground ivy and white clover.

“There’s some great white clover as a high-level type of plant that can be mixed into the lawn,” Epstein said. “It’s drought tolerant. It needs less water. It flowers, it’s good for pollinators. And it helps your soil.”

An added benefit to clover: Rabbits love it.

“They’ll also eat that on your lawn rather than your plants,” Epstein said.