Green tomatoes that fail to ripen after a hot summer can be encouraged to turn red and juicy with a simple trick from gardening expert Monty Don. The method involves picking the fruit and storing it in a drawer alongside a banana.
Why tomatoes stay green
In a blog post from 2024, Monty explained that tomatoes ripen best when the temperature is between 26C and 30C. This summer, like two years ago, has been too hot for tomatoes, especially those grown in a greenhouse, leaving many fruit green for much longer than usual.
Monty said: "However, by September, the heat is running out, and inevitably, we are all left with green tomatoes that are never going to ripen."
The banana trick
Monty added: "However, if you pick them either individually or on the vine, then put them in a drawer with a banana, they will ripen and turn red." The banana releases ethylene, a hormone linked to fruit ripening, which speeds up the process. Apples also give off the same gas, but bananas tend to work better and are cheaper to use.
Gardeners should check the drawer regularly and remove tomatoes as soon as they have ripened. The RHS also recommends the banana trick and suggests that at the end of the season, outdoor plants with unripe fruit can be lifted and laid on straw under cloches, or the fruit can be picked and placed somewhere warm and dark to ripen.
Checking maturity and planting advice
To check whether green tomatoes are mature enough to ripen, gardeners can cut one in half. If the inside is yellow with sticky tissue around the seeds, it is ready. All similar tomatoes can then be picked, cleaned of vines, twigs and stems, and placed in a drawer.
For growing tomatoes from scratch, the best time to sow is February, March or April, indoors in warm conditions, moving plants outside once the risk of frost has passed. Frost damage can stunt growth and result in dead fruit.
