Trouble in Tomato Land – why all the green tomatoes?

By Linda Weiford, WSU News

Green-tomato-webPULLMAN, Wash. – If you planted garden tomatoes this year, you may be wondering why they seem stuck on green.

Area gardeners are reporting that, with few exceptions, the popular backyard crop is taking its sweet time ripening. Although many tomato plants are teeming with big orbs, most are as green as Granny Smith apples.

“I’m very disappointed in the growth of my tomatoes this year and have heard from other growers who feel similarly,” said volunteer master gardener Debbie McNeil with Washington State University’s Whitman County Extension. “I planted the same variety in the same spot where previously they had done very well. This summer, they’re definitely lagging.”

Green tomatoes. (Photo by Linda Weiford, WSU News)

A pattern of zig-zaggy weather temperatures since early June has slowed the ripening process, she said.

“While we’ve had warm and hot days, we’ve also had a number of cooler ones,” she said. “Consequently, tomatoes haven’t had an optimal number of what we call ‘growing degree days’” – a measurement of heat accumulation within a certain temperature range.

Those cool temperature dips – like what we’re experiencing this week – have reduced the number of growing degree days by 10 so far, said McNeil.

That shortage put tomatoes about a week and a half behind schedule, said Randy Gilmore, an avid tomato grower and owner of Sun Mountain Natives, a distributor of hand-collected native plant seeds based in Moscow, Idaho.

“Tomatoes got off to a shaky start in early June when high temperatures went from being in the 90s to the 50s in a matter of days,” he said. Since then, similar fluctuations have occurred, though fortunately not as extreme.

Will summer’s great gift to the table even make it to the table?

Yes, said Gilmore and McNeil, who offer two simple words of advice: Be patient.

“They should catch up later this month and the rewards will be well worth the wait,” said McNeil.


Debbie McNeil, WSU Whitman County Extension, 509-397-6290,
Linda Weiford, WSU News, 509-335-7209,