Tomatoes Not Ripening in Pots? What to Do Now
Tomatoes in pots stop ripening mainly because the temperature has moved out of the range that ripening needs, not because you did something wrong. Pick the fruit that has reached the mature green stage, shiny skin with a pale star on the blossom end, and finish it indoors at 55 to 70 degrees Fahrenheit. Fruit that is still matte, dull green will not ripen off the plant. And unlike a garden bed, a pot can simply be moved.
Why tomatoes in pots stall at green
Ripening is a temperature-driven process, and it has a fairly narrow comfort zone. University of Illinois Extension horticulture educator Christopher Enroth puts the optimum range for ripening tomatoes at 68 to 77 degrees Fahrenheit, and notes that temperatures above 85 degrees stop the plant producing lycopene and carotene, the pigments that make a tomato red. That is why fruit can sit for weeks looking yellowish-green instead of coloring up. The same guidance flags excess water and low light levels as problems, because both affect the plant's uptake of potassium.
Late in the season the failure runs the other way. Days shorten, nights cool, and the fruit sits below the range rather than above it. Nothing is diseased and nothing is dying. The plant has simply run out of the conditions it needs to finish the job it started.
Two things make this sharper in a container than in the ground. A pot holds a small volume of mix with air on every side of it, so it tracks the air temperature far more closely than soil does, warming faster by day and cooling faster at night. And a container plant usually carries a heavy fruit load relative to its root volume, so whatever energy it has is divided across every tomato on it at once.
How to tell which green tomatoes will still ripen
This is the single check worth doing before you touch anything else, because it decides what you do with every fruit on the plant.
Colorado State University Extension describes the mature green stage as fruit that is a shiny green with a white to light green star shape on the blossom end. Those tomatoes have finished growing and will ripen indoors, though the guidance is honest that flavor development is incomplete compared with fruit left to ripen on the plant. Fruit that is still matte and dull, with no star, has not reached that stage. It will not turn red in a bowl on the counter.
So the job is sorting, not rescuing. Go over the plant once and put the fruit into three piles: anything with a blush of color, anything mature green, and everything else. The first two piles are food. The third pile is the plant's unfinished work, and it is the pile that tells you whether the remaining plant is worth keeping going at all.
If the only fruit left after that sort is small, hard and matte, the plant has nothing it can still deliver this season, and the honest move is to pull it and get the pot cleaned out rather than nurse it through another three weeks.
Move the pot, not just the fruit
Here is the part written for a container grower and almost never for anyone else, because the pages that rank for this question are written for an in-ground garden with fifteen plants in a row. Those growers have exactly one option when the weather turns: pick everything and bring the fruit inside.
You have a second option. The plant is in a container, which means the whole growing system is portable. A pot that can be lifted can be moved to the warmest position you have, and on a small balcony that is usually hard against a wall that has had sun on it all day, out of the wind, rather than out on an exposed edge or a railing. A pot that can be carried can come inside for the night and go back out in the morning while the air is still in the range the fruit needs.
This is not a way to grow new tomatoes. Nothing set now is going to size up. It is a way to buy ripening days for fruit that is already mature green and sitting just below the temperature it needs, and it often turns a bowl of counter-ripened tomatoes into a few that finished on the plant, which is the version that actually tastes of something.
The limit is honest too. Moving a pot is only worth it while the plant has fruit worth finishing and while the pot is a size and weight you can genuinely handle, and it is not worth hurting your back over six tomatoes. If the plant is in a half-barrel, pick the fruit instead.
Ripening picked tomatoes indoors, without turning them to mush
Once the fruit is off the plant, the whole thing becomes a storage question. Colorado State's guidance is specific and it is worth following rather than improvising: remove the stems, wash the fruit and let it air dry on paper towels out of direct light, then arrange it in layers one to two tomatoes deep in a covered box or a container, with newspaper or cardboard over it, somewhere dark and cool.
Temperature decides the speed. Stored between 55 and 70 degrees Fahrenheit, fruit held near 70 ripens within a couple of weeks, while fruit near 55 takes around a month. Below 50 degrees, the same guidance says, tomatoes go bland, which is the usual reason a fridge is the wrong place for this.
Humidity decides the losses. Too much and the fruit molds, too little and it shrivels. To raise humidity, Colorado State suggests putting the tomatoes in a strainer or blanching pan set inside a covered container with water in the bottom, with the fruit not touching the water. To speed things up, add a banana or one or two already red tomatoes to the box, which supplies the ethylene that pushes the color change along.
Check the box every few days and take out anything that has colored or anything that has gone soft. One rotting tomato in a closed container will take several others with it.
| What you have | Where it goes | Roughly how long |
|---|---|---|
| Fruit with any blush of color | Counter, out of direct sun | A few days to a week |
| Mature green, shiny, pale star | Covered box near 70 degrees F | Up to about two weeks |
| Mature green, cooler spot near 55 degrees F | Covered box, dark | Around a month |
| Matte green, no star | Will not ripen; cook it green | Use within days |
What to do with the fruit that will never ripen
Matte green tomatoes are still food, they are simply not going to be red food. They are firm and sour and they behave in a pan more like a vegetable than a ripe tomato, which is why almost every traditional use for them is a cooked one.
What this site does not do is tell you how to can, pickle or ferment them. Those processes are a food safety subject with tested, published procedures behind them, and a gardening guide is the wrong place to improvise one. If that is where you want to take the harvest, the National Center for Home Food Preservation publishes the tested processes, and the right move is to follow one exactly rather than adapt it.
For a container harvest the question is usually smaller than that anyway. A handful of green tomatoes is a side dish, not a pantry project, and the storing-a-small-harvest problem is the one most balcony growers actually have. The approach in the guide to storing homegrown vegetables with one fridge applies here: sort first, use the fragile things first, and do not refrigerate what refrigeration ruins.
Setting next season up so it does not happen again
Three things decide whether you are reading this page again next autumn, and all three are decided early.
Days to maturity, read off the packet. Every seed packet and plant tag states how long the variety takes from transplant to first ripe fruit. That number, counted back from the point your own weather reliably drops out of the ripening range, is the whole planning calculation. Small-fruited and early varieties carry shorter numbers, which is why they so often finish on a balcony where a big beefsteak does not.
Feeding, timed to the stage. A plant pushed hard with nitrogen while it is carrying fruit puts its effort into leaves. The same restraint that applies to feeding container flowers without burning them applies to a tomato pot, with the extra wrinkle that container mix is fed on a schedule rather than holding reserves of its own, so it is genuinely easy to overdo.
Fruit load, decided by you. A container plant carrying thirty green tomatoes in September is dividing a small root system's output thirty ways. Taking off the youngest, smallest fruit that has no realistic chance of finishing concentrates what is left. It feels wasteful and it is not, which is the same counterintuitive logic behind picking more often producing more.
One more thing worth knowing: the plant does not owe you a second act. When the fruit is in, the next decision is the pot, not the plant, and the where to store pots over winter in an apartment problem arrives immediately after this one.
FAQ
Will green tomatoes ripen if I leave them on the plant?
Only while the temperature stays in range. Colorado State University Extension's guidance is to harvest before consistent freezing temperatures arrive, because frost ends the question. If your nights are already cold and the fruit is at mature green, it will usually finish faster indoors than outside.
Does the paper bag trick work?
It is a real method. University of Illinois Extension describes picking fruit showing a lighter green or a little blush and ripening it indoors in a paper bag with holes punched in it, taking one to five days. The holes matter, because a sealed bag traps the moisture that causes mold.
Why are my tomatoes orange or yellowish instead of red?
That pattern points at heat rather than cold. Temperatures above 85 degrees Fahrenheit hinder the plant's production of lycopene and carotene, per Illinois Extension, and fruit ripened through a heat wave often colors unevenly as a result.
Should I pull the plant or keep it going?
Sort the fruit first. If nothing on the plant has reached mature green, there is no harvest left to wait for and the plant is using the pot. If several fruits are mature green, keeping the plant in the warmest spot you have for another week or two is worth it.
Can I keep the plant through winter and get fruit again next year?
A tomato is grown as an annual and a container plant that has finished a season is spent. The thing worth keeping is the pot and the habit, not the plant.