You’ve been delicately caring for your tomato plants all summer and looking forward to that first delectable, juicy fruit. But you’ve been waiting and waiting and waiting for your green tomatoes to turn red. They just aren’t ripening. What gives?
Generally, tomatoes take from six to eight weeks from the time of pollination to reach maturity, based on the variety you’re growing and weather conditions.
“There are several factors that impact when tomatoes will ripen,” says Nate Muri, founder of Garden Like a Viking and Viking Growing System. “There’s often a perception about when they ‘should’ ripen, but that can be influenced by many things.”
When it comes to slow ripening, it’s generally not something you did or didn’t do. “The plants will produce ripe fruit in time,” says Frank Hyman, author of Ripe Tomato Revolution and former organic tomato farmer. “They’re not holding out on you. It’s the conditions that control what’s going on.”
Learn why your tomatoes are still green and what you can do about it.
Why aren’t my tomatoes ripening?
It's a common problem. “Although we think of tomatoes as a summer crop, fruit development nearly halts during hot weather,” says Chris Enroth, horticulture educator with University of Illinois Extension. “For tomato fruit development, the ideal daytime temperature range is about 70 to 85°F, while nighttime temperatures of 60 to 70°F are ideal for pollination, fruit set, and fruit development.”
Much like you feel sluggish in hot weather, tomato plants aren’t happy when it’s too warm either. “As day temperatures increase above 85 degrees, fruit development slows,” says Enroth. “Once daytime temperatures go above 95 degrees and nighttime temperatures stay above 75 degrees, pollination pretty much stops. It is too hot for pollen to remain viable. The plant will abort its flowers, and this is when we often see a lull in tomato fruit development.”
Humidity also plays a role in pollen viability. “In areas of the United States that experience high humidity like the Midwest, we can also experience gaps in tomato fruit set,” says Enroth. “Relative humidity above 70 percent causes the pollen to clump and stick together making it difficult for flowers to become pollinated. So, even if you’re seeing normal flowers, if the relative humidity has been high for several days, the flowers will have reduced pollination.”
In addition, when temperatures soar to the 90s and higher, lycopene and carotene, the pigments responsible for giving the fruits their coloring, can’t be produced. As a result, the fruits remain green, says Muri.
Can you make green tomatoes ripen faster?
Unfortunately, no. You’ll simply have to sit back and hope for cooler days to come. “If you have green tomatoes, you are going to have to wait it out,” says Hyman. “This is an opportunity to develop your patience. You have to reconcile yourself to nature’s pace.”
The tomato plant itself is usually not permanently harmed by a short period of hot weather. “Once temperatures moderate, flowering, pollination, and fruit set typically resume,” says Enroth. Fruits begin to ripen again, too, when temps drop.
One trick you can try toward the end of the season is to pinch off flowers and small fruits you know will not have time to develop into tomatoes. “This will allow the tomato plant to dedicate more resources ripening the more mature fruits on the plant,” says Enroth.
Finally, if you’re impatient to pick your first tomato, go ahead and harvest them when the first signs of red appear on them. While this isn’t going to make them ripen faster, it typically prevents them from developing unsightly cracks, which can occur with uneven soil moisture levels, says Hyman.
Arricca Elin SanSone is a writer, editor, and content creator who specializes in lifestyle and gardening. With a background in health reporting, she applies these same research skills when writing about the science of growing things. She trials new plants in her expansive garden, and her houseplant collection consists of 60+ varieties. Arricca has written thousands of articles for publications such as Country Living, House Beautiful, Good Housekeeping, Prevention, VERANDA, Southern Living, and more. She’s happiest when digging in the dirt, baking, or spending time with the people and dogs she loves.
