How to ripen green tomatoes on a plant?

Jaime BeamerMarch 4, 2023

0 56 5 minutes read

Tomatoes have been my favorite produce since I began gardening. Every spring I start at least a dozen varieties from seed, some that I’ve purchased and some that I’ve fermented and saved.

I like the kaleidoscope of colors—from milky white to deep indigo—as well as the seductive scent of tomato leaves that cover my hands after rummaging through the vines for perfectly ripe fruit.

Nevertheless, at this time of year, the same thing that provides me joy—harvesting baskets of tomatoes—can also be a cause of irritation, particularly in Central Oregon, where the season is short and the fruits develop slowly.

Every year, no matter how early they were planted inside or within greenhouses, there always seem to be a few holdouts that stubbornly remain green when the temperature starts to turn dangerously near to freezing.

That’s because, as a tropical perennial in its native Peruvian highlands, land of everlasting summer, the tomato plant lacks the same molecular cues that urge other plants to wind down and generate seed when temperatures begin to fall.

This implies that your tomato plants will continue to produce blossoms and fruit until they are pruned or destroyed by frost.

So you don’t have to make another batch of pickled green tomatoes this year… at least not right away.

Try a handful of these easy tips to speed up ripening when the days shorten and the temperature cools!

Contents

Trick #1: Pinch off the top of the plant.

If you’re only a few weeks away from the first frost and still see a fair amount of green tomatoes on the vine, the best way to promote faster ripening is to pinch off (cut) the top of your tomato plant—just remove the tip of the main stem above the topmost blossom. This inhibits the plant’s ability to grow higher and produce more blossoms.

I also pluck any green fruits that have not yet achieved maturity. Without its resources being wasted on growing fruit to full size, the plant can channel its energy into ripening the fruit it’s already produced.

Some studies have shown that reducing the number of fruit not only speeds up ripening, but also improves the size, flavor, and nutrient content of the harvest. Therefore it’s a win-win situation!

Trick #2: Induce stress.

Inducing stress is a simple approach to help tomatoes to mature quicker.

If tomato plants believe their life is threatened, they will accelerate the maturity of their fruits in order to generate seed and develop the next generation of plants.

Just lowering the quantity of water they get might cause stress. Let the plants to acclimatize gradually by providing less and less water each time during a three-week period. You don’t want to overstress the plants at first (which could cause blossom end rot, split fruits, or cracks).

This deliberate withholding of water is akin to the dry farming approach used by commercial growers to boost taste.

The fruits are smaller than tomatoes allowed to mature on the vine under normal circumstances, but limiting the plant’s water intake boosts the sugar content and other taste compounds in the fruits, resulting in sweeter and richer tomatoes.

Therefore, in addition to helping your fruits mature faster, this approach may provide you with a nice extra!

(But, I should point you that just not watering your plants is not an optimum technique to produce tomatoes. A successful crop of dry-farmed tomatoes has to be dry-farmed from the beginning under specific climate and soil conditions.)

Trick #3: Try root pruning.

Another simple technique to cause stress is to prune the roots, which disrupts the plant’s growth cycle. This special technique hampers the plant’s absorption of water and sends out distress signals, telling it to hurry up and ripen the tomatoes it’s produced.

To do this, simply insert a spade 6 to 8 inches deep into the soil, about 1 foot away from the main stem, and move it in a circle around the plant. This will cut the plant’s outermost roots, causing it to develop more quickly than it would otherwise.

In general, the optimal time to root prune a tomato plant is after the first few clusters of fruits have formed but before they start to mature.

In my location, I normally do this three to four weeks before the first frost, however time may vary depending on your garden and environment.

When you combine root trimming with decreased watering (as described in technique #2 above), your “laziness” at the end of the season will pay off with better-tasting, more nutritious fruit and less waste in the garden!

Trick #4: Ripen tomatoes indoors with a bit of apple peel.

If an early frost has forced you to bring in all of your unripe tomatoes, you may speed up ripening by putting them in brown paper bags with a little of apple peel inside (loosely and in single or double layers, not packed thickly on top of each other).

Apples produce a lot of ethylene, a colorless, odorless, naturally occurring gas that softens the flesh and raises the sugar content (a process we know as ripening).

With the help of ethylene, your green tomatoes should ripen in a week, as opposed to the two weeks it generally takes mature green fruit to ripen.

And picking mature green fruits is essential for properly ripening tomatoes inside. These are the ones that have reached full size and may have a tiny yellow hue on the exterior. As you cut a sacrificial piece of fruit, you should notice a gelatinous feel and a color change on the interior.

Green tomatoes that are mature have the highest chance of ripening off the vine. Sort and separate yours according to stage of ripeness, as it’ll help you discern when each batch is ripe and ready by checking only a few test fruits (instead of needing to open and check the whole bag).

For optimal results, keep the unripe fruits in a cool, dry area in the home at temperatures between 65°F and 70°F—never refrigerate them, since this not only stops the ripening process but also renders the flesh mealy after extended cold exposure.