Why your tomatoes won’t turn red in the heat — and when you should pick them

(Image credit: Shutterstock) It’s been an extraordinary summer. I’ve never known a season when the temperature has been so high without any rainfall.My area is officially in drought, and unsurprisingly my lawn and yard are looking parched. It’s easy to see which plants and flowers are heat and drought-tolerant, and I’m making a mental note of what to concentrate on growing next year.Everything is behaving differently; even my tomato plants are responding to the high temperatures. Where they would usually be turning red, they are stuck in between color changes.I’ve been watering my tomato plants consistently, making sure they’re hydrated without overwatering. However, there’s one element that is outside of my control.Tomatoes react differently to extreme temperatures (Image credit: Shutterstock)According to Holly from the Garden Tendencies Instagram channel, high temperatures impact the color change in tomatoes.“Once it stays above 85 degrees [29.4°C], tomato plants stop making the pigment that turns fruit red. So your tomatoes sit there, full-sized and stuck between green and orange, never finishing,” she says.Without knowing that the temperature halts the process, you may hold off harvesting your homegrown crop, but she advises against keeping them on the vine.Get instant access to breaking news, the hottest reviews, great deals and helpful tips.Instead, Holly suggests, “Pick at first blush, the moment you see any color, and let them finish on the counter.”But don’t worry, you won’t notice the difference in the taste.“The flavor difference versus vine-ripened is less than 1%. You’re not sacrificing taste, just outsmarting the heat,” she adds.How high heat stops tomatoes turning red (Image credit: Shutterstock)Tomatoes need temperatures between 70°F and 75°F to build color properly. When the temperature reaches between 85°F and 90°F, the high heat stops the fruit from making the red and yellow pigments (lycopene and carotene), which it needs to change color.The intense heat causes the ripening process to slow or stop completely if the high temperatures persist. Bonnie Plants explains, “Fruit left on plants may have some color on the outside, but may still be green inside. So, if a period of intense heat is in the forecast, pick any fruit already showing hints of ripe color and allow it to finish ripening indoors.”My tomatoes are still looking green, without the first sign of a blush, but I’m going to wait a little while longer to see if they start to turn. Let me know in the comments whether you’ve noticed a difference with the lack of color change in your tomatoes this year, and whether you’ve already started to pick them off the vine. Follow Tom's Guide on Google News and add us as a preferred source to get our up-to-date news, analysis, and reviews in your feeds. More from Tom's GuideHow to get rid of tomato blossom end rot for a healthy harvest7 mistakes to avoid when growing your own tomatoes3 ways to tell that your tomatoes are ready to harvest Camilla is the Homes Staff Writer and covers everything to do with homes and gardens. She has a wealth of editorial experience, mounting over 30 years, and covers news and features, tests products for reviews and compiles buying guides. Her work has appeared in business and consumer titles, including Ideal Home, Real Homes, House Beautiful, Homebuilding & Renovation, and Kitchen & Bathroom Business. She’s even appeared on the cover of Your Home, writing about her own house renovation. Although she’s obsessed with decorating her home, she also enjoys baking and trying out the latest kitchen appliances. But when she’s not inside, you’ll find her pottering about in her yard, tending to her vegetable patch or taking in her prized hydrangeas.