Monty Don’s expert tip for ripening green tomatoes

The taste of a sun-ripened tomato from your own garden is truly something, but now that September has arrived, some of the harvest we’ve carefully tended may never be red and ripe.

But don’t despair if you think that you’ve enjoyed the last of these wonderful fruits from your plot. Dedicated tomato grower – and of course gardening expert, author and broadcaster – Monty Don has come to the rescue with a really rather amazing tip on ripening green tomatoes.

When you know how to grow tomatoes, use this neat trick and you can relish the taste of the summer for just a little while longer.

Monty Don’s top tip on ripening green tomatoes

Monty Don revealed the secret of ripening green tomatoes on his website. Now we’re sharing his advice, plus some of our own expertise.

But, first, why haven’t tomatoes ripened well this year? Whether you've been growing tomatoes in raised garden beds or pots, Monty says that they ripen best when the temperature is between 79 and 86ºF (26 and 30ºC). In other words, in many gardens it’s been too hot this summer, and particularly if the tomatoes are under glass.

Contrary to what you might expect, this has meant that many tomatoes have stayed green much longer than when the summer is cooler, Monty explains.

But, with the heat on the wane now September is here, the result is green tomatoes that will never ripen, he says.

There is a solution for ripening green tomatoes, though. The secret, according to Monty, is to pick them either individually or on the vine from your kitchen garden.

Then, all you have to do is put your green tomatoes in a drawer with a banana, and they will ripen and turn red, he says. 

Why a banana? It will naturally give off ethylene gas which promotes the ripening of fruit. Tomatoes give this gas off, too, but the presence of the banana will help ripen them. And why put the green tomatoes and the banana in a drawer? It traps the gas.

More ways to ripen green tomatoes

There are alternatives to Monty’s trick with green tomatoes. Whichever you use, bear in mind that the green tomatoes you pick should nevertheless be mature and full or almost full size. 

Don’t wash the tomatoes before you try these methods as you don’t want them to develop mold (you should, of course, always wash them before eating). 

1. Instead of putting the tomatoes into a drawer with a banana, put them into a paper bag along with a banana or an apple (sample principle), and close the bag up. Take a look each day and serve any tomato that’s turned red and ripe.
2. Swap the drawer or paper bag for a cardboard box and place the tomatoes inside but apart from one another. Again, add a ripe banana to help things along. Close the box. Check daily and eat each tomato when ripe.

Using these methods, like Monty’s, ripening takes a week or two. 

Our top tip? Don’t store these containers of tomatoes in the fridge; the tomatoes should remain at room temperature. The room should be around 65 to 77ºF (18 to 25ºC).

If you want even better results with your tomatoes next year, don't forget that it's worth including the best companion plants for tomatoes in your veg plot to help boost the yield of your tomato crops and protect them from pests.