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How to Ripen Tomatoes in a Greenhouse

12 Easy Tips on How to Ripen Tomatoes in a Greenhouse

Do the tomatoes in your garden refuse to ripen? Have you tried every trick you knew of and prayed to God for days but have not seen any results yet? Well, growing tomatoes can be a little frustrating like that.

However, it doesn’t have to be impossible. If your tomatoes refuse to ripen, keep reading to learn how to ripen tomatoes in your greenhouse.

A Little Bit About Growing Tomatoes

Who doesn’t love tomatoes? The juicy fruits go well with a range of dishes, they’re nutritious, and they’re tasty enough to be eaten on their own as well. And when you grow them yourself from your own garden, somehow they taste that much sweeter and juicier. Now you’re probably thinking that growing a tomato plant is easier said than done.

We’re not saying it’s a walk in the park, but growing your very own tomato plant isn’t impossible either. All you need is a little knowledge about growing a tomato plant and a few tips and tricks on how to ripen green tomatoes for some of the best tomatoes you will ever have.

Tomatoes are a warmth-loving fruit, which is why summers are the best time to grow them. However, with the proper precautions and conditions, you can have your tomato plants bearing fruit all year long. When growing from seeds, you can plant the tomato fruit around March to April, and if you plan to grow them in a greenhouse, you can start even earlier, from around late February.

As mentioned earlier, tomatoes love a warmer temperature, and therefore, for the best produce, they should get at least six to eight hours of full sun every day. Tomato plants also require loads of nutrients to grow strong and healthy. Therefore, you should plant them in nutrient-rich soil or lots and lots of compost. But, be careful not to go overboard with the nutrients or fertilizers as that just brings a whole new set of problems.

Moreover, tomato plants can also get quite heavy and start to droop on the ground. That’s why you need to add a stake, trellis, or cage to support the plant as it grows and keeps the fruit off the ground. Remember to keep space between your tomato plants for adequate air circulation and ventilation.

Otherwise, it can get quite humid and invite trouble. Another reason you want to keep the tomato plants off the ground is to prevent them from rotting or spoiling from growing on the ground. Although, some tomato varieties can be grown on the ground as well.

Tomato plants grow best in temperatures between 55 and 75 degrees Fahrenheit. Anything below 50 degrees and above 85 degrees Fahrenheit will stop the tomato plants from growing. Therefore, whether you’re growing the tomatoes outside or in a greenhouse, make sure the plants have the ideal temperature day and night.

How to Ripen Green Tomatoes in Greenhouse

Whether you’re a beginner or expert at growing tomatoes, it’s always a good idea to brush up on the basics of growing tomatoes. And if you are here reading this right now, it’s probably because you’ve grown the tomatoes and are now sick and tired of waiting for the plant to turn the tomatoes green to red. We get it. The tomato ripening process can be a long and exasperating one at times.

However, you don’t need to torture yourself any longer over not being able to turn that tomato green to red. With these easy tips and tricks, you’ll be enjoying your home-grown ripe tomatoes in no time. Here’s what you can do.

1. Add More Protection to Help the Ripening Process

When growing tomatoes, the only thing that’s really stopping you is the oncoming winter season. Once that frost sets in, you will have no chance of ripening that green tomato, and you will have to wait till spring or summer next year.

However, you can give your ripening process a bit more time by delaying the frost from setting in your plants. And the best way to do this is to add more protection to your plants.

Even when you are already growing the plants in a greenhouse, you can add more protection by setting up a polytunnel over the plants. These can help protect your tomatoes from excessive heat as well as snow, frost, and sunlight.

They can also work great for other plants and are effective all year round, so it’s a win-win situation. Specifically when it comes to ripening tomatoes, a polytunnel can help extend the growing season a bit longer so that green tomato can finally turn red and juicy for you to enjoy.

2. Raise the Temperature Around the Green Tomatoes

Tomatoes also ripen faster when they have a warmer temperature to grow in. Therefore, raising the temperature around your tomato plant should help the green tomatoes to ripen faster. There are several ways to do this.

You can add bubble wrap or some thermal mass to the structure to insulate it against the cold weather outside. You can also add manure and compost to the soil as it will warm up the soil bed and provide some warmth to help the tomatoes ripening process.

Additionally, you can also introduce some heating source inside to raise the temperature artificially. You can place an electric heater or a solar-powered one if you’re concerned about the environment. You can install some sort of a water heating system that will add heat as the hot water flows through the pipes.

Whatever you do, make sure the temperature doesn’t go over 85 degrees Fahrenheit as that will only harm your plant. Install a thermostat to keep an eye on the temperature.

Furthermore, sunlight doesn’t always equal warmth. In fact, too much sunlight can also be harmful to your ripe tomatoes, as it will cause the skin to harden. This is also why ripening tomatoes on the windowsill isn’t always that effective.

3. Place Other Ripening Fruits to Speed Up the Ripening Process

Another effective way to ripen green tomatoes is to place other ripening fruits with it. This works while the tomatoes are planted as well as if you pick it off early and need to ripen a green tomato indoors.

You can place a ripening banana or even an apple under the plant, and it will help accelerate the tomatoes’ ripening process. The science behind this is that the ripening fruits, such as banana or apple, release ethylene gas, which helps in ripening. (source)

When the green tomatoes absorb this ethylene gas from the other ripening fruits, it helps with their own ripening as they are able to mature faster. This is also why you might have noticed your other fruits rotting or getting overripe if placed alongside bananas in a bowl.

Additionally, once the fruits have helped ripen tomatoes, they will rot and decompose into the soil, adding nutrients to it for an even healthier tomato plant and no waste!

You can do this while the green tomatoes are still on the vine. Otherwise, if you happen to pick a few tomatoes early for any reason, you can place them in a brown paper bag along with ripe fruit, and it will help the tomato ripen quicker.

4. Place an Additional Cover Over the Green Tomatoes

Adding on to the previous point, if you want to speed up the process of ripening tomatoes even further, you will have to concentrate the release of ethylene gas on those fruits and prevent it from diffusing elsewhere.

And the best way to do this is to add another layer or cover over the tomatoes. You can create another mini polytunnel for a set of tomato plants or add some fabric or cloche over individual plants.

This additional layer will help contain that release of gas to that particular area and allow it to have a stronger effect on the green tomatoes. The more gas that builds under the layer, the faster it will help ripen the tomatoes.

However, you have to be careful while doing this. As your tomatoes start to turn red, you must pick the ripen tomatoes right away, or else they could become overripe and start rotting and then start spoiling the other fruits in the bunch as well.

5. Go Easy on the Watering

This is a problem that most gardeners and home growers face when they are trying to grow a plant. Overwatering is one of the easiest ways to kill any plant, and a tomato plant is no exception. Especially when you’re trying to ripen green tomatoes, excess watering does not help anyone. Therefore, when you are specifically trying to ripen your green tomatoes, go easy on the watering.

You must have already watered the plant enough while growing it from seed to its current fruit-bearing stage and all during the summer. However, at this point, you can cut back on watering the plant. As the water level goes down, the plant will realize that it needs to quickly mature the fruits and start producing seeds to survive.

Ultimately, this will push the green tomatoes to ripen quickly and turn red and juicy. You don’t need to stop watering it all the way as that can dry out your plant and cause it to wither and die. However, you should reduce the frequency of watering according to the temperature and other weather conditions. If you had been watering it every day, now would be the time to water it every second or third day.

6. Remove any Rotten or Spoiled Tomatoes Right Away

This holds true for almost any plant you grow, but you should keep a close eye on your tomato plants when you’re waiting for the fruits to ripen. This means watching out for any bugs, pests, and even rotten and spoiled fruits. Rotten fruits can destroy a plant as well as any bug, and therefore, while you’re looking for any creatures on the plant, take a minute to inspect the fruits as well.

Check all the green tomatoes for any spoilage and if you do find one, remove it from the rest of the bunch right away. This is because fruit rot can easily spread to other healthy fruits and destroy the whole batch. Problems like blight can affect your plant any time of the season, whether it’s in the early or late stages of growth. (source)

Moreover, removing the rotten or affected fruit not only prevents it from spreading to the other fruits but also ensures a healthier and better yield of ripe fruits. This is because once the rotten fruit is off the plant, the plant doesn’t have to spend extra energy trying to fight off the disease and can channel that saved energy into ripening your tomatoes faster and bearing more fruit.

7. Trim Excess Foliage of the Plant to Fasten the Ripening Process

Similar to removing the rotten tomatoes, another way to ripen tomatoes faster is to trim some of the excess foliage of the plant. This also has several benefits. Firstly, by trimming some of the extra foliage of the plant, you can reduce the size and volume of the plant. This means that the plant now has more energy to spend on each part of the plant, including the unripe tomatoes.

Therefore, the extra energy helps the fruits mature faster and turn red and ready to be picked. Secondly, sometimes, the foliage can also block the tomatoes from receiving proper sunlight as they come in the way. So, by removing some of that foliage, you allow the tomatoes to receive adequate sunlight again, which is crucial for their growth and ripening.

8. Cut Away New Flowers

Flowers are always a beautiful sight and a signal that your plant is bursting with life. Moreover, it is ultimately those flowers that bear the fruits. Normally, this is a good thing. However, when you’re in a race against time, with winters approaching and the dangers of frost looming, or if you simply want to ripen your fruits right away, flowers aren’t such a good idea.

They clearly won’t have the time to mature into full fruits before the season is over, and therefore, at this point in time, they will just be a drain on the plant’s energy and resources. That’s why when you want to ripen your tomatoes, you should cut away these new flowers. That will save some energy, which can then be channeled into maturing and ripening the tomatoes.

9. Remove Small Fruits to Ripen Tomatoes Faster

Similar to what we’ve mentioned above, removing small fruits also helps to ripen tomatoes. It follows the same principle. The new buds and small fruits won’t have time to fully mature this season, and therefore they would be using up extra energy. Removing these small fruits helps free up that energy that can then be used to ripen the green tomatoes.

However, if you are not in any rush to ripen the tomatoes or there’s still plenty of time left in the growing season, you can let these small fruits and new flowers remain on the plant. Instead, you can use some of the other tricks we have mentioned to ripen your tomatoes.

10. Give the Plant a Shock to Ripen Green Tomatoes

You can also ripen tomatoes by giving the plant a shock. No, we don’t mean an electric shock, so you can place those car batteries back. However, they will have the same effect on the plant. Giving a shock to a plant is fairly simple. All you need to do is lightly pick up the plant by the stem and give it a slight shake to loosen the roots.

This shock gives the plant a surprise scare and puts it into a survival mode. In this mode, the plant gets in a hurry to produce seeds to survive, and to do that, it must take care of the fruits first. Therefore, it starts working to quickly ripen the tomatoes so that those can be picked off, and the plant can focus on producing new seeds.

11. Water the Soil and Not the Tomatoes

Prevention is always better than cure, and if you want to ripen your tomatoes, you have to first ensure that the tomatoes stay healthy enough to survive and ripen. One way to ensure this is to keep the plant and especially the tomatoes dry.

When watering the plant, direct the watering close towards the soil and make sure the tomatoes don’t get wet. Late in the season is a popular time for the blight to attack, and when the tomatoes are wet, there is a higher chance of getting hit by the blight.

12. Pick Off the Almost Ripe Tomatoes

You can also choose to ripen some tomatoes indoors, as we mentioned previously. You can place the pinkish tomatoes in a brown paper bag or a shoebox lined with some paper towels in a warm place. The warmth will help ripen the tomatoes.

You can also place another ripening fruit with it to speed up the ripening of the tomatoes. Additionally, the more fruits you pick off the plant, the more energy will free up for the rest of the still unripe tomatoes.

Why Are Your Tomatoes Not Ripening?

Sometimes you might be doing everything right, but your tomatoes will still refuse to ripen. You could use all the tricks we’ve mentioned, and they might still not work. In that case, it could be some other factor that is apparently stopping your tomatoes from ripening.

For instance, it could be that you are growing a specific variety of tomatoes that naturally take a longer time to mature and ripen. In that case, you can do everything you want, but eventually, it will ripen at the time it is supposed to.

Additionally, another reason could be temperature. As we’ve mentioned earlier, there’s a temperature range that tomatoes thrive in. Outside that range, they won’t survive. It could be that the temperature at night is dropping too low or high and preventing the tomatoes from ripening. (source)

Furthermore, another reason could be that your tomatoes have ripened already, and you just don’t realize it. Some varieties of tomatoes stay green even after ripening, and it could be that you are waiting for a tomato to turn red that never will.


Once you’ve tasted fresh, homegrown tomatoes, you probably won’t ever go back to the store-bought ones. Thankfully, with these tricks on how to ripen tomatoes in your greenhouse, you won’t ever need to.

So, which trick will you try first?

Let us know in the comments down below!