How to Ripen Green Tomatoes Quickly Indoors

Tomatoes are one of the most popular garden plants, and understanding how to ripen tomatoes is important when you grow them. Unless you live in a protected greenhouse, your outdoor tomatoes probably fall victim to pests before they get the chance to fully ripen, or perhaps you have a short growing season where they can’t ripen on the vine.

It may seem your only option is to pick them while they are green, but is it easy to ripen them indoors? What is the best method for ripening tomatoes? Also, are there methods that can slow down or speed up the ripening process?

In this article, I’m going to share the best method for ripening tomatoes indoors, along with some tips and tricks. I know all too well what it is like to have tomato problems, and it can be tough when you don’t yield much due to issues with ripening.

These days, I have much more success because I ripen almost all my tomatoes indoors. Indoor ripening has also taught me how to ripen tomatoes faster or slower. By slowing down the process, it is possible to have fresh tomatoes even in the winter.

What Is Ripening, Anyway?

Before we get into how to ripen your tomatoes, we first have to understand ripening as a process. Ripening is the transformation process that gives tomatoes their signature red appearance and their sweet, fresh flavor. When a tomato fruit ripens, the green chlorophyll breaks down, and red color pigments come to the surface.

As it ripens, the tomato decreases in tannins, which are responsible for the sourness of green tomatoes. Ethylene gas, which is present in aging fruits, helps break down cell membranes. As a result, the tomatoes become softer. This is why they ripen faster when they are around riper tomatoes. As the tomatoes become softer and sweeter-smelling, they also attract pests.

If left outdoors, most tomatoes will be eaten before they become pink. You will have much better results if you pick them when they are still green but just beginning to ripen. They can easily be ripened indoors to reach their most delicious red color.

What Color is Your Tomato?​

How ripe your tomato is can be determined by the color on the outside. This standard can be applied to all kinds of tomatoes, including cherry tomatoes. There are six tomato color classifications recognized by the USDA: green, breakers, turning, pink, light red, and red.

If your tomato is completely green, ranging from light green to dark green, it is the furthest from being ripe. Once your tomato begins to show a little yellow, pink, or red, it is said to be in the ‘breaking’ stage. When 10 to 30% of the tomato’s surface is showing yellow, pink, red, or a combination of these colors, it is ‘turning.’

After the turning stage, your tomato will become pink, meaning that 30 to 60% of the tomato’s surface shows a red color. Next is the ‘light red’ stage, meaning more than 60% of the surface is pink or red. The final stage is ‘red,’ which is when more than 90% of the surface shows red color.

Some varieties may be slightly different depending on their natural color, like yellow Sun Gold, orange Pineapple, or the green and yellow Green Zebra. Check your specific variety you’re growing to determine their color when ripe.

Other Methods

You might wonder, ‘can I bring my tomato plants indoors to ripen the tomatoes on the vine?’ You can, but tomato plants carry things like bacteria, microbes, and mold spores, so bringing the plant inside will also contaminate your home. This will quickly contaminate other tomatoes you have picked off the plant.

Commercial growers might tout ripening methods that include chemical treatments of oxygen and ethylene. However, you don’t need to get that technical. In the right conditions, your tomatoes will ripen just fine on their own.

You might think, ‘sun-ripened tomatoes are a thing—doesn’t that mean I can ripen them in a sunny window?’ Well, not exactly. Light is not required for ripening, and it will actually make the skins harder. The heat will cause the tomatoes to ripen too quickly, and if they become too warm, they will rot. Sun-ripened tomatoes are different than window-rotted tomatoes.

You can indeed ripen your tomatoes in a paper bag or wrapped in newspaper placed in plastic bags. These methods do work. However, they take longer and are harder to regulate than the method we’re going to discuss right now!

How to Ripen Green Tomatoes Indoors​

There are a variety of methods that can be used to ripen green tomatoes indoors. I have experimented for years, and have found that simpler is often better. This method is fairly easy, but it has also given me the most success.​

Here is a list of items you will need.​

• A wide, flat box or container
• Absorbent material, such as a towel or paper towels
• Thermometer
• Dehumidifier (if the ripening area is humid)

Step 1: Pick Your Tomatoes

If a tomato is hit by frost, it will turn dark green and cease to ripen. Therefore, it is important to pick green tomatoes off the vine before a threat of frost. Only pick the tomatoes that are shiny and green, or green with a little pink. The smaller, white tomatoes will not ripen well indoors. This applies to cherry tomatoes, slicers, and paste tomatoes.

Step 2: Wash and Sort

Wash the tomatoes under cold, running water. You’ll want to use running water so you can wash all the dirt and bacteria down the drain and avoid cross-contaminating the tomatoes. As you do this, also remove any stems so they will not accidentally puncture other tomatoes.

If you have any tomatoes that are soft, bruised, or blemished, separate them from the firm and clean tomatoes. You can attempt to ripen the damaged tomatoes, but if left with the good ones, they may cause them to rot.

Step 3: Prepare a Container

You will ripen the tomatoes in a flat, wide container. Cardboard produce boxes are ideal. The container you use must have an absorbent surface, such as thick cardboard.

Line the bottom with something absorbent, like a towel or paper towels. This absorbs moisture from any tomatoes that start to rot. If the liquid from rotting tomatoes touches other tomatoes, it will cause the good tomatoes to rot more quickly.

Step 4: Place the Tomatoes

Place the good tomatoes in a single layer at the bottom of your container, spacing them 2 to 3 inches apart. To avoid the spread of rot, the tomatoes should be spaced so they are not touching.

You can speed up the ripening process by including a ripening banana, apple, or other piece of fruit, which will diffuse ethylene into the unripe tomatoes. If you go this route, ensure you’re checking the box frequently, as the ripening process will be much faster than it would be without them.

Step 5: Store

Store this box in a cool, dry area that is 50 to 65°F (10 to 18°C). Basements, garages, or indoor porches can all be good storage areas. High humidity will cause more rotting and increase the chance of mold, so you may need to use a dehumidifier.

Good air circulation is also important for preventing mold. Cooler temperatures, from 50 to 60°F (10 to 15°C), will cause tomatoes to ripen more slowly. Higher temperatures, from 60 to 65°F (15 to 18°C), will cause more rapid ripening. Make sure the tomatoes don’t reach temperatures below 50°F, or they may become soft and never turn red.

Check on the tomatoes every day, or once a week at the very least. Remove any rotting tomatoes as soon as you see them. Check for rot at least every other day, because any rot will spread quickly to other tomatoes. When the tomatoes become 50% red, remove them from your box and continue to let them ripen in your kitchen.

It should take between 3 weeks to 3 months for your tomatoes to finish ripening. With careful monitoring and temperature control, you can cultivate a yield of tomatoes that lasts through the winter!

Storing Ripe Tomatoes

You may have heard that you shouldn’t store nightshades in the refrigerator. However, that’s just not the case for tomatoes. While it may be true for peppers, eggplants, and the like, tomatoes do just as well when stored in a cool, dark fridge. In fact, they won’t degrade as quickly as if stored on the counter.

If you have a perfectly ripe tomato that you’re not going to eat right away, the refrigerator will keep it at the same ripeness it was when you placed it inside. It should keep for up to 2 weeks this way, as long as you haven’t cut into it.

As you might already know, cold tomatoes don’t have as much flavor as room-temperature ones. So, when you take the tomato out of the refrigerator for slicing or cooking, let it come to room temperature first. Then enjoy its full flavor.

It’s still viable to store your tomatoes on the counter, but they may not last as long. Whether you choose to store them in the fridge or on the counter, turn them blossom-end up. As we’ve discussed, tomatoes ripen from the bottom up, and storing them on their stems will assist in this process.

Additionally, storing them with the blossom end pointing toward the ceiling distributes the tomato’s weight more evenly, preventing weight-driven deterioration over time.

Frequently Asked Questions