Ask Dave Epstein: How to help your blighted tomatoes

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.

Have a gardening or weather question for meteorologist Dave Epstein? Tweet him @GrowingWisdom, email us at thewakeup@wgbh.org, or text 617-300-2008.

I am limited to growing my veggies in pots on my deck. I have been very successful but now with all this rain, I am concerned about my tomato plants needing a "life jacket." Any suggestions to assure they don't rot, develop blight or other issues with over watering? — Diane in Marlborough

There are plenty of organic options for preventing blight and rot in tomatoes, Epstein said.

If you notice tomato plants’ leaves turning yellow or dropping, it may be time to use a fungicide.

He recommended two brands of organic fungicide: Serenade and Monterey. If those don’t work, try a copper-based fungicide.

“The copper product is kind of the strongest one,” Epstein said. “So it's like if you go to the doctor’s and you get the antibiotic. The Serenade and the Monterey products, those are kind of the initial. If that's not working, you go to the copper, but don't start with start with the copper, because that's kind of the last vestige.”

Is there a particular crop that is going to benefit from the influx of rain? — Jason in Melrose

More rain typically means larger fruit — but also less flavorful fruit.

“With too much water, the sugars are not as concentrated and things don't taste as sweet,” Epstein said.

But some crops thrive: Lettuces, peas and some root crops, like carrots, kohlrabi and beets, Epstein said.

If you haven’t planted any vegetables yet, it’s not too late.

“You can still put some seeds in,” Epstein said. “I planted some kales, lettuces. In another couple of weeks, you could put in some peas and get a nice fall crop.”

What is the best way to get rid of powdery mildew on squash plants? — Craig LeMoult, GBH News reporter

The same organic fungicides that will help blighted tomatoes will also help get rid of that mildew, Epstein said.

“There are synthetic products out there, but they are chemicals which are not approved for organic gardening,” Epstein said. “So there are some broad spectrum things if the organic stuff isn't working.”

Why are so many beaches closed for high bacteria levels? Can I still go into the water?

All of the recent rain on the Massachusetts coast is responsible for those higher bacteria levels.

“What happens is that you have pollutants that are in the ground. The heavy rain washes that in,” Epstein said. “It overwhelms the system of those beaches.”

The bacterial counts will eventually level out naturally, Epstein said. But in the meantime, some beaches may be closed. Bacteria may vary — some can be dangerous if people accidentally ingest them, others can cause skin irritation or other issues.

“As you have the tides coming in and out, it's kind of cleaning it out. The bacteria levels go up and it takes several days, or in some cases it could take a week or more, to kind of get that bacteria out of there,” Epstein said.

The same phenomenon is responsible for shellfisheries closing in New Hampshire and Maine, he said.

“They can't harbor shellfish for the same reason — the high levels of bacteria — because of the heavy rain,” Epstein said.

Bottom line: Check with local authorities before heading to the beach, Epstein said. There may be restrictions keeping people from going in the water.

July 3 was the hottest day in recorded human history — immediately beaten by July 4, with a global average temperature of 62.92 degrees Fahrenheit, according to the University of Maine's Climate Reanalyzer. What does that mean?

“It's big in the sense that it just keeps confirming what we already know: That the planet's warming up,” Epstein said.

The temperature measurement is considered preliminary, but Epstein said he considers it valid.

“It was done scientifically,” he said. “But it's got to be confirmed. It's like one of those things that they'll have to go back and look. And I think we're going to actually see even warmer temperatures here over the next four to six weeks, where that record will probably end up being broken.”