Meteorologist Dave Epstein is our go-to person for pressing weather questions on everything from winter blizzards to summer droughts. He’s also a horticulturist, meaning he’s an expert in anything that grows leaves and flowers. GBH's Morning Edition asked our audience for weather and gardening questions, and Epstein graciously answered them on the air. This transcript has been edited for clarity.
Since it is officially autumn and getting cooler outside, when is the last time you should mow your lawn?
Autumnal lawn mowing is a delicate balance, Epstein said.
“You don't want to leave your lawn super short going into winter and you also don't want to leave it super long,” he said.
He tends to aim for a length of 2 ½ to 3 inches, he said.
“Sometimes, if you have a warm fall, you can end up having to mow it into early December. It just depends on how cold it is, as we move through the next couple months,” he said. “I would say that after you've had several kind of harder frosts and you notice it sort of slowing down.”
Do we need to do any type of special lawn grass care before the winter season?
First: Put away regular lawn fertilizers.
“There are some late fall fertilizers you can put out, but any of the other fertilizers, you also want to stop that because it promotes what's called snow mold, and that gets on the grass and it literally looks like a little mold that you see in the spring up with the snow melts and it can damage your lawn,” Epstein said.
Epstein said he looks for organic, slow-release fertilizers for his own lawn in the fall.
It’s also a good time to deal with soil pH levels.
“Here in this part of the country, our soils tend to be fairly acidic. So putting down some lime is a good thing,” he said. “I like the pelletized stuff better than the powdered stuff because the powdered stuff gets into the air and you end up breathing it.”
The limestone may take several months to work its way into the soil, he said.
With all of this rain, we have clusters of mushrooms popping up in our yard. Should we be concerned? We are pulling them up and definitely not eating them. But is there anything else we should do to prevent our yard from turning into a mushroom farm?
No need for concern, Epstein said. Leave them be.
“There's probably something dying underneath there that the mushrooms are feeding on,” he said. “Just leave them. They're not a problem.”
Mushrooms, he said, are “a really cool organism.” And while some are edible, it’s indeed a bad idea to eat them unless you are absolutely certain that you can identify them correctly.
“There's a few really great ones that are out there that are edible: chicken of the woods, hen of the woods, there's some chanterelles that I've seen popping up this time of year. But you’ve got to know what you're doing,” he said.
My peonies are very sick. They have brown spotted leaves. What should I do?
“I noticed the same thing,” Epstein said. “I suspect it's all the water we've had. There's some fungus and bacteria that attack those. Hopefully the rootstock is okay.”
Epstein’s advice: Cut back any of those spotted leaves and get rid of them.
“Removing the leaves will stop the spores from kind of spreading again next year,” he said.
In a few months, once the ground freezes hard, add some fresh mulch around them for the winter, he said. With any luck, they’ll bounce back next year.