Can you plant tomatoes on Mother’s Day? Memorial Day? Be patient

by Connie Oswald Stofko

by Connie Oswald Stofko

“Let me tell you a story,” said Kelly McDonald, executive director and Master Gardener at Cornell Cooperative Extension in Cattaraugus County.

“Last year my husband and I planted tomato seeds in the house with grow lights. The plants were getting bigger, so we moved them into gallon buckets. The weather got warmer and we moved the plants in and out of the garage (to protect them from cool nights).

“Then we got a warm stretch of weather. We got so excited. It was hot and sunny, so my husband decided we should plant the tomatoes in the garden.

“On May 22, we got a frost. It killed all the tomato plants.

“We lost over 60 plants.”

That frost last year hit the Southern Tier, but surprises like that can happen throughout Western New York.

Why planting times are so variable

Climate change

Our growing season in Western New York is longer than it used to be—two weeks longer than it was in 1965, according to Stephen Vermette, professor of geography in the Department of Geography & Planning at SUNY Buffalo State University.

Now the growing season starts about a week earlier in spring and lasts about a week longer in autumn.

Weather

Climate is the average of the weather patterns in a location over a longer period of time, usually 30 years or more. Weather is what you get when you walk out the door.

Do you remember 2020? We had a mild winter. April was beautiful and I expected to glide seamlessly from spring to summer. Instead, May took a step back into winter with snow, and in some areas, the snow accumulated.

That’s weather. And weather in Western New York is difficult to predict.

Where you live

When will you get your last frost? It depends on where you live. Note: Frost can occur even when the air temperature is above freezing, due to cold air settling, microclimate variations and other factors. Many frosts occur when the air temperature is in the mid-30s.

At the Buffalo International Airport there is a 90 percent probability that April 22 will be the last date to have a low of 36 degrees Fahrenheit. However, there’s still a 10 percent chance that there could be a low of 36 degrees as late as May 19. Statistically, it’s probable that one year out of 10 will see a low of 36 degrees as late as May 19.

For Jamestown there is a 90 percent probability that May 4 is the last date for a low of 36 degrees, with a 10 percent chance that June 2 could have a low of 36.

See the last frost for other Western New York areas on the page with U.S. Climate Normals from the National Centers for Environmental Information, part of the National Oceanic and Atmospheric Administration (NOAA).

It may be easier for you to find your town on this map from NOAA Climate.org. The map shows the average date on which the chance of freezing temperatures drops below 50 percent. That means that it’s probable that temperatures will stay above 32 degrees Fahrenheit for the rest of the season.

You can plant now, but . . .

Tender plants such as tomatoes need more than just a frost-free day. The nighttime air temperatures are important, too.

“You can plant your tomato plants when it’s 45 degrees or warmer at night,” McDonald said, “but it’s better to wait.”

It’s best to plant when days are 60 to 65 degrees Fahrenheit during the day and 50 degrees at night, she said.

If plants are subjected to temperatures that are too cold, the tomato could result in catface, McDonald said. The fruit can be mildly to severely deformed, appearing puckered and lumpy.

And if you plant too early, you might get a setback instead of that head start you think you’re getting.

So can you plant on Memorial Day? Mother’s Day?

Years ago, people saw Memorial Day as the time to safely start our gardening season. Now many gardeners race to get plants outside by Mother’s Day.

When can you plant tomatoes and other tender plants outside? Keep these things in mind:

• The climate and weather are different throughout Western New York, so there is no one-size-fits-all for every part of WNY.
• Western New York’s climate is getting warmer, so you may be able to plant sooner than you could in 1965. But that doesn’t mean that you can plant sooner this year than you did last year.
• The rules of thumb about planting on a certain holiday were never definitive starting times. They are estimates—informed guesses.

Let’s take a look at Mother’s Day. It falls on May 12 and the forecast is:

• Buffalo: high of 57, low of 52
• Lockport: high of 63, low of 49
• Chautauqua: high of 60, low of 48
• Little Valley: high of 58, low of 43

A couple of these areas are expected to have nighttime temperatures that are warm enough for tomatoes on Mother’s Day. But the weather can still change after Mother’s Day.

“You don’t know what Mother Nature might do,” McDonald said. “It’s better to wait.”

How to make a decision

Use these steps to make a decision on when to plant:

• Find the last spring freeze date for your area.
• Check the weather forecast for your area.
• Choose whether you want to take a chance or play it safe.
• What to do if it doesn’t work out. (If you do get cold nights, you can cover your plants to protect them, McDonald noted.)

Other plants

• Eggplant and potatoes need the same conditions as tomatoes. You can start potatoes early underground, but you don’t want the leaves showing above ground until the weather is warm, McDonald said.
• There are cool weather vegetables that you can plant very early.
• Here are more plants that can tolerate cold as well as some that can’t.