Do your tomatoes look like this? They may have Blossom End Rot. Jean Faucett/Shutterstock

For me, tomatoes make late summer what it is – although corn, beach days, agricultural fairs and visits from friends and relatives each add their own elements to the season.

We harvested our first tomatoes, both bite-sized and slicers, in late July this year, greatly improving our lunches and salads and giving me a brief burst of pride.

Compared to last year, when the weather was cool and soggy, our crop is hugely improved. But a friend who has successfully grown tomatoes in past years sent us  photos of her tomatoes this summer, which looked like they had been devastated by diseases. The few fruits that seemed to be ripening well and disease-free got eaten by critters, she said.

I went to the state’s “Got Pests?” website to see if I could help. It was easy to scroll down the website and find tomatoes that looked like the ones in the friend’s photos. The culprits seemed to be catfacing and blossom end rot. (Keep in mind that this diagnosis is not from an expert but from a guy who likes to garden and gets paid to write about it.)

An indigo cherry tomato grows in columnist Tom Atwell’s garden in the summer of 2022. Photo by Tom Atwell

The good news is that if my diagnosis is correct, those problems are not diseases. They are what Got Pests calls “physiological problems.” Catfacing is caused by cold weather at the time of blossom set and blossom end rot by calcium deficiency related to fluctuations in available moisture. I can understand how both of those could happen.

We’ve all read about climate change and nowadays we experience a lot of mid-May warm days, which makes us rush to plant the tomato seedlings before the traditional May 30 Memorial Day guidance. The odd cool night can hit the blossoming tomatoes and cause blossom end rot. And we may think we have plenty of rain, but one dry spell with warm temperatures can cause the plants dry out. One thing to remember is that tomatoes, wonderful as they are, are a tropical plant and they’re fussy when asked to grow in New England. So wait until the temperature is reliably warm before you plant them, and then make sure that they get plenty of water.

We have run the sprinkler on our gardens only twice thus far this summer. If we have two or three days without rain, I get water from our rain barrels and douse all the warm-weather vegetable plants – squash and cucumbers, as well as tomatoes – some flowers and anything in containers. My wife Nancy says I do it just to build up my step count, but really, that’s just a side benefit.

I was pretty sure even before going to Got Pests? that the tomatoes were not victims of the more serious and occasionally widespread problems of Late Blight or Early Blight. As a member of the Maine Organic Farmers and Gardeners Association, I subscribe to Caleb Goosen’s Pest Report. He reported on Aug. 9 that Late Blight had been detected near Presque Isle in Aroostook County, but as of my writing this, it had not been found elsewhere in the state. Upstate New York has been hit harder, though.

Late Blight affects both potatoes and tomatoes. It’s what caused the Irish potato famine, 1845 to 1852, that in turn caused huge numbers of Irish to immigrate to the United States. To prevent Late Blight, he advises removing the lower branches on tomato and potato plants to ensure they get a bit of air circulation, and applying copper fungicide, which is allowed on organic crops, before light rains and after heavy rains.

It is too late this year, but Pamela Hargest, of the Cumberland County Cooperative Extension, recommends a list of disease-resistant tomato plants that you can find on the website of Cornell University. Or read the labels on the tomato seed packets and the tomato plants you buy. Look for resistant tomatoes and save yourself from disappointment. Specifically, you’ll want to buy tomato seedlings that have VFNT resistance, which stands for resistance to verticillium wilt, fusarium wilt, root knot nematodes and tobacco mosaic virus.

Truthfully, I don’t know what those problems are, but they don’t sound good.

Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at: tomatwell@me.com