How to ripen green tomatoes, the quickest method is to pick them and put them in a bowl or paper bag with a ripe banana, somewhere warm and dark, and they will turn red in a week or two. On the plant, you speed things up by removing the lower leaves, pinching out the growing tip in late summer, and easing off the watering so the plant stops making new growth and puts its energy into the fruit it already has. Warmth is what actually does the work, not sunlight, which is the bit most people get wrong.
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Every August I have the same conversation with someone over a fence: plants loaded with tomatoes, not one of them turning red, and a growing worry that the whole lot is going to waste. It is one of the most common questions I get, and the good news is that ripening is easy to nudge along once you understand what the plant is actually waiting for. After twenty years of growing them on heavy Oxfordshire clay, I have tried most of the tricks, and a few of them genuinely work while the rest are folklore.
Why Tomatoes Go Red: It Is Warmth, Not Sun
Here is the thing almost everyone gets wrong, myself included for years. Tomatoes do not need direct sunlight to ripen. They need warmth, and they need a gas called ethylene, which the fruit produces itself. Sunlight helps the plant grow and it warms the fruit, but a green tomato will ripen perfectly well in a dark drawer as long as it is warm enough.
The sweet spot is roughly 20 to 24C. Below about 10C ripening more or less stops, which is why the crop stalls as autumn cools. And here is the counter-intuitive part that catches people out in a hot summer: above about 30C the plant stops making lycopene, the pigment that turns tomatoes red, so in a heatwave your fruit can sit stubbornly green or turn a patchy yellowish orange. If that is happening to you, the plant is not sick, it is too hot, and there is nothing to do but wait for the weather to settle. The RHS covers the growing side in detail if you want the background.
Once you understand it is about warmth rather than light, every method below makes sense, because they are all just ways of keeping the fruit warm and surrounded by ethylene.
How to Ripen Green Tomatoes on the Vine
If the plant is healthy and there is still warmth left in the season, the best tomatoes are the ones you ripen on the plant. You just help it along. The single most effective thing is to stop the plant growing, because as long as it is putting out new leaves and flowers it is spending energy on growth rather than ripening. From early to mid August, pinch out the very top of each cordon plant two leaves above the highest truss you want to keep. This is called stopping, and it tells the plant the season is ending.
At the same time, strip off the lower leaves up to the first truss of fruit. This lets light and warm air get at the trusses and improves airflow, which also cuts the risk of disease. Keep removing any new side shoots too, the same way you would earlier in the season, which I cover in removing side shoots on tomatoes. Finally, ease back on watering. A plant that thinks a drought is coming panics slightly and throws its energy into ripening the fruit it has, so slightly drier is better than lush at this stage. Just do not let it wilt hard. There is more on getting that balance right in how often to water, and the wider late-summer care sits in how to care for tomato plants.
How to Ripen Tomatoes Indoors, Off the Vine
Sometimes waiting on the vine is not an option. The nights have turned, blight is threatening, or the season is simply over. When that happens, pick the green tomatoes and ripen them indoors, which works far better than most people expect once you know it is ethylene doing the job.
The classic method is a paper bag or a bowl with a ripe banana or apple, which pump out ethylene and set the tomatoes off. Keep them somewhere warm, around 18 to 21C, and out of direct sun, which can scald them. Check every couple of days and remove any that are ripening or, worse, going soft, because one rotting fruit will take the rest with it. A single layer in a cardboard box lined with newspaper works just as well as anything fancy. Wrapping individual fruits in newspaper slows them down if you want to spread the harvest out over weeks rather than have them all at once.
One tip worth knowing: only fruit that has reached full size and started to lighten from dark to pale green, or shown the first blush of colour, will ripen well indoors. A tiny hard dark-green tomato picked in September has not developed enough and will more likely shrivel than redden, so those are the ones for chutney.
Ripening a Whole Plant at the End of the Season
When frost is forecast and a plant is still covered in green fruit, do not pick them one by one. Lift the whole plant, roots and all, and hang it upside down somewhere warm and dry like a shed, a garage or a spare room. The fruit keeps drawing on the plant and ripens gradually over the following weeks, and you get a much better result than picking everything green in a panic.
If frost has not quite arrived but is close, you can also buy a week or two outdoors by covering the plants at night. A layer of garden fleece thrown over the row on cold nights holds enough warmth to keep ripening ticking along and protects the fruit from a light frost. Knowing when your first frost is likely helps you plan all of this, and the frost date checker gives a date for your postcode. Clearing the last of the tomatoes is one of the jobs I list in August gardening jobs, and it dovetails with what to sow in September as the beds start to clear.
How to Ripen Tomatoes Quickly
If you want the fastest result, the banana-in-a-paper-bag method is hard to beat. The confined space concentrates the ethylene from the banana around the tomatoes, and in real warmth they will often colour up in three to five days rather than the week to two weeks a bowl on the side takes. An apple does the same job if you have no banana.
What does not work is the internet advice you will see about ripening them on a sunny windowsill. It is the most common suggestion and one of the worst, because a windowsill cooks one side in direct sun while the fruit stays cool, and you end up with soft, unevenly coloured tomatoes with tough patches. Warm and shaded beats bright and hot every time. There is no genuine way to ripen a tomato overnight, whatever you read, but the paper bag is as close as it gets.
Why Your Tomatoes Might Not Be Ripening
If the fruit is simply refusing to turn red on the plant, it is usually one of a handful of causes, and none of them means the plant is beyond help. Cool weather is the most common in a British summer, since ripening slows below 10C and the plant is just waiting for warmth. A heatwave is the opposite problem, stalling the colour above 30C. Too much leafy growth is another, where the plant is busy growing rather than ripening, which is exactly what the stopping and leaf-stripping above fixes.
Overfeeding, especially with a high-nitrogen feed, pushes the same leafy growth at the expense of fruit, so switch to a high-potash tomato feed once fruit has set. And sometimes it is simply too late a crop, where plants that went in late are only fruiting as the light fades. If your plants are struggling in other ways as well, it is worth working through common tomato problems, and if they are flowering but not even setting fruit, that is a different issue covered in tomato plants not producing fruit. Yellowing leaves alongside slow ripening point to why tomato leaves turn yellow.
What to Do With the Green Ones That Never Turn
Every year there are stragglers, the small hard green tomatoes that were never going to ripen. Do not bin them. Green tomato chutney is one of the genuine pleasures of the end of the tomato season, and it turns a glut of unripe fruit into jars of something you will still be enjoying at Christmas. Fried green tomatoes are worth a go too if you have never tried them.
I have come to see the green ones not as a failure but as a second harvest, and it takes the anxiety out of that first frost warning. Whatever has not ripened becomes chutney, and nothing is wasted. The BBC Gardeners’ World tomato guide has more on end-of-season care if you want another view.
Getting Ahead of It Next Year
Half the ripening battle is won long before August, at planting time. The single biggest cause of a late, green-heavy crop is starting too late, so plants that go in on time have the whole warm season to fruit and ripen. My guide to when to plant tomatoes covers the timing, and growing tomatoes in the UK pulls the whole thing together.
Variety matters too. Cherry types like Sungold ripen far earlier and more reliably in our climate than big beefsteaks, which often run out of summer before they colour up. And a greenhouse changes everything, holding the warmth that ripens fruit and extending the season at both ends. If you are still getting seedlings established each spring, how to grow tomatoes and why tomato seedlings go leggy will help you raise stronger plants that fruit earlier. Outdoors, growing a blight-resistant variety also means you are less likely to be forced into picking everything green because blight has struck, which is a common reason people end up ripening indoors in the first place.
How to Ripen Green Tomatoes: Frequently Asked Questions
How do you ripen green tomatoes quickly?
Put them in a paper bag or bowl with a ripe banana or apple, somewhere warm around 18 to 21C and out of direct sun. The ethylene from the fruit ripens them in three to five days.
Do tomatoes need sunlight to ripen?
No. Tomatoes ripen with warmth and ethylene, not light. A green tomato will turn red in a warm dark drawer, which is why the sunny windowsill trick often fails.
What temperature do tomatoes need to ripen?
Around 20 to 24C is ideal. Ripening slows below about 10C and stalls above about 30C, when the plant stops making the red pigment.
How do you ripen green tomatoes on the vine?
Stop the plant by pinching out the top in August, strip the lower leaves, remove side shoots, and ease off watering so it puts energy into ripening rather than growth.
Can you ripen green tomatoes indoors?
Yes, and it works well. Pick full-sized green tomatoes, keep them warm with a banana or apple nearby, and check every couple of days, removing any that soften.
Why are my tomatoes staying green and not turning red?
Usually cool weather, a heatwave over 30C, too much leafy growth, overfeeding with nitrogen, or a crop that went in too late. Stopping the plant and stripping lower leaves helps.
What do you do with green tomatoes at the end of the season?
Full-sized ones can be ripened indoors with a banana, or the whole plant hung upside down somewhere warm. Small hard green ones are best turned into chutney.
How long do green tomatoes take to ripen off the vine?
Usually one to two weeks in a warm spot, or three to five days if enclosed with a ripe banana. Warmth is the main factor, so cooler rooms take longer.
A Sensible Place to Start
If your tomatoes are green and you are not sure what to do, start with the simplest thing. Pick a few of the biggest, put them in a bowl with a ripe banana somewhere warm, and watch them turn over the next week. That one small experiment shows you it is warmth and ethylene doing the work, not sunshine, and once you trust that, the rest falls into place.
For the fruit still on the plant, stop it growing in August, strip the lower leaves, and let the season do its job. And when the first frost warning comes, do not panic-pick everything green. Ripen what you can indoors and turn the rest into chutney. Handled that way, the end of the tomato season stops being a race against the weather and becomes just another part of the harvest.