- What Is Ripening, Anyways?
- What Color is Your Tomato?
- How to Ripen Green Tomatoes Indoors
- Frequently Asked Questions about Tomato Ripening
Tomatoes are one of the most popular garden plants. They are tasty, versatile, and easy to grow. However, unless you live in a protected greenhouse, your outdoor tomatoes probably fall victim to pests before they get the chance to fully ripen.
It seems 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 depressing when you don’t yield much due to problems with ripening.
These days, I have much more success because I ripen almost all my tomatoes indoors. Indoor ripening 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. Using this method, I have more control over when the fruits get ripe, and I am much more successful in obtaining a crop of unblemished, tasty red tomatoes.
What Is Ripening, Anyways?
Before we get into how to ripen your tomatoes, we have to understand ripening as a process first. 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 of the tomato breaks down and red color pigments come to the surface.
Timelapse of a ripening tomato. Created from this video
As it ripens, it decreases in tannins, which are responsible for the sourness of green tomatoes. Ethylene gas, which is present in aging fruits, helps to break down cell membranes. As a result the tomatoes become softer. This is why tomatoes accelerate in ripening 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 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. There are 6 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 10-30% 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 turn pink, meaning that between 30-60% of the tomato’s surface will show a red color.
Then, the light red stage means that more than 60% of the surface is pink or red.
The final stage is red, and this is when more than 90% of the surface shows red color.
How to Ripen Green Tomatoes Indoors
There are a variety of methods that can be used to ripen tomatoes indoors. I have experimented with different methods and tricks 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
- 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 the green tomato 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.
Step 2: Wash
Wash the tomatoes under cold, running water. You’ll want to use running water so you can wash away all the dirt and bacteria down the drain, and not cross contaminate the tomatoes. As you do this, also remove any stems, so that the stems will not accidentally puncture other tomatoes.
Step 3: Sort
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 bad tomatoes, but if they are left with the good ones, they may cause the good ones to rot.
Step 4: Create the Ripening Area
You will ripen the tomatoes in a flat, wide container. Cardboard produce boxes are ideal. You can get these boxes when you buy fruit at Costco or Sam’s Club. However, any cardboard box should also work.
The container you use must be made of an absorbent surface, such as thick cardboard. You will need to layer the bottom with something absorbent, like a towel or paper towels.
This will absorb 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 5: Place the Tomatoes to Ripen
Place the good tomatoes in a layer at the bottom of your container, spacing them 2-3 inches apart. To avoid the spreading of rot, the tomatoes should also be spaced apart so they are not touching.
Step 6: Store the Container
Store this box in a cool, dry area that is 50-65ºF (10-18ºC). Basements, garages, or indoor porches can all be good areas for storing. High humidity will cause more rotting and a higher chance of mold, so you may need to use a dehumidifier.
Good air circulation is also important for preventing mold. Cooler temperatures, from 50-60ºF (10-18ºC), will cause tomatoes to ripen more slowly. Higher temperatures, from 60-65ºF (15-18ºC), will cause more rapid ripening. Make sure that the tomatoes don’t reach a temperature under 50ºF, or they may go soft and never turn red.
Step 7: Monitor the Tomatoes
It is best to check on the tomatoes every day. Check on them once a week at the very least. Remove any rotting tomatoes as soon as you see them. It is best to check for rot at least every other day, because rot will spread quickly to other tomatoes. When tomatoes become 50% red, remove them from your box and continue to let them ripen in your kitchen.
Step 8: Enjoy Your Ripe Tomatoes!
It should take between 3 weeks to 3 months for your tomatoes to finish ripening. Through some careful monitoring and temperature control, you can cultivate a yield of tomatoes that lasts through the winter!
Frequently Asked Questions about Tomato Ripening
Q. Can I ripen tomatoes by bringing my tomato plant inside?
A. 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 that you have picked off the plant.
Q. Are there any chemical products needed for ripening tomatoes?
A. I do not recommend any chemical products. In the right conditions, tomatoes will ripen on their own just fine.
Q. Can placing a banana near the tomatoes cause them to ripen faster?
A. Yes, ripe fruits like bananas release ethylene gas, which is one of the factors that leads to ripening. You can also use apples.
Q. Do the tomatoes need to be stored at an exact temperature?
A. It definitely helps the ripening process when they are kept at within the recommended temperature range. Keeping them at a consistent temperature also helps you predict how long it will take for them to ripen. In cooler temperatures, tomatoes will ripen more slowly.
Q. Do the tomatoes need to be picked before frost?
A. It is best if they are. Tomatoes will die well before freezing temperature, and if the tomatoes are damaged by frost they are not likely to ripen. If frost has already damaged the plant, you may be able to save and ripen the tomatoes that were covered or on the inside part of the plant.
Q. Can tomatoes be ripened indoors next to sunny windows?
A. No. 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 to warm they will rot.
Q. How important is it for the tomatoes to ripen in certain temperatures?
A. The temperature makes a significant difference. Warmer temperatures from 60-68 F can be used to ripen them faster, and cooler temperatures from 50-58 F can be used to slow them down. If the tomatoes are too cold, however, they will be stunted and never turn red. This is why you should never put green tomatoes in the fridge.
Are there other methods that work well, such as wrapping the tomatoes in newspaper or putting them in plastic bags?
I have tried these methods, plus many more, and I have had the most success with the method I have described above.
Tomato ripening is fairly simple, and overall it yields a better crop. Because I have seen the struggles of tomato harvesting first-hand, my hope is that every gardener would know how to ripen tomatoes.
If you have suggestions, questions, or tomato-ripening experiences that you wish to share, please feel free to leave them in the comment section. Also, if you enjoyed this article, please share it with other gardeners!
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