What you're learning
- What makes tomatoes ripen?
- How long does it take for tomatoes to ripen?
- How to look after your tomato plants so that they produce ripe tomatoes
- Check the variety of tomatoes and the color the tomatoes should be – it could be a green tomato variety
- How do you ripen late-season green tomatoes?
- How do you ripen green tomatoes off the vine?
- Common myths about growing and ripening tomatoes
- Tomato glut? How to store and preserve your ripe tomatoes
- How to make sweet tomato jam with your surplus ripe tomatoes
Nothing compares to the excitement of spotting the first baby tomatoes on your beloved tomato plants after nurturing them for months. From the moment the tiny tomatoes appear, it’s hard to stay patient as we want them to grow bigger quickly and ripen into beautiful, cheery red fruits.
But sometimes it seems to take forever for tomatoes to ripen and turn red, and you might still have plants laden with green tomatoes while the season is rapidly coming to an end.
So, how do you turn green tomatoes red? And how do you encourage your tomatoes to ripen before it’s time for the final harvest in October? Find out how to ripen green tomatoes successfully using several simple methods.
What makes tomatoes ripen?
The fruit ripening process is a slow one, but it’s fairly simple.
Firstly, tomatoes need to reach maturity (be fully grown) at their green stage. This is determined by the variety of tomatoes, with smaller varieties reaching maturity first and ripening first. For example, little cherry tomatoes will reach a mature green state before the much larger beefsteak variety.
Tomatoes also need warmth to ripen, although they don’t actually need continued direct sunlight to ripen. In fact, too much direct sun can damage them, causing sun scorch.
A temperature of between 50 – 85 F (10 -29 C) is essential for turning those green tomatoes red. This temperature range enables the production of lycopene and carotene, two organic compounds that are essential to the ripening process and creating the red color of ripe tomatoes.
If it’s too hot, tomatoes will stop ripening too, so it’s important to regulate the temperature of the environment where your tomato plants are growing if you can.
Another chemical needed for the ripening process of tomatoes is ethylene, a plant hormone that is released in gaseous form by ripening fruits. Ethylene gas makes fruits ripen by converting the starch it stores into sugar.
The ethylene gas from other ripening fruits can trigger and speed up the ripening of green fruits! This is why you might have heard that putting ripe bananas in a bag with unripe tomatoes can make the tomatoes ripen quicker.
It’s also why you might need to separate fruits if you don’t want them to cause each other to become over-ripe.
Supermarkets control the amount of ethylene that their fruit is exposed to, usually increasing the amount of ethylene artificially in order to make fruit ripe and ready to eat. They also extend the shelf life of fruits by adding sachets that absorb ethylene gas to packaging that contains fruit to prevent it from ripening too quickly.
It’s important to note that artificially produced ethylene gas isn’t a substance available to the public, in case you were hoping to purchase some to ripen your own tomatoes! But there are methods that use the naturally produced ethylene gas to your advantage to ripen fruits more quickly, as you will learn shortly.
How long does it take for tomatoes to ripen?
From seed to ripe tomato on the vine
The growing season of most tomato varieties is quite long – anywhere from 6-9 months from seed to harvest – and ripening time depends on environmental factors. A consistent warm temperature is important, although direct sunshine doesn’t always help as it can toughen the skins of the tomatoes.
If you’re growing tomatoes indoors or in a greenhouse, it will be a lot easier to ensure a consistent temperature and you should have reliable ripening of tomatoes on the vine. Growing tomatoes indoors also reduces the risk of pests and diseases damaging your tomato crop, and you can extend the growing season.
Once off the vine, tomatoes will ripen in the right conditions anywhere from a few days to two weeks, depending on how unripe they are. The ripening process for tomatoes removed from the vine depends on creating the right environment – they need to be somewhere warm, dry, and indoors.
How to look after your tomato plants so that they produce ripe tomatoes
Tomato plants are tender and heat-loving, which is important to remember when planning on growing your own. If you live in a warm climate that generally has higher temperatures and less rainfall in summer, you could try growing your tomatoes outdoors in your garden.
Growing tomatoes in a greenhouse is a great option regardless of the climate as you will have more control of the immediate environment that they will be growing in. A greenhouse will protect your young plants from frost, keeping them warm and safe as they grow and the tomatoes ripen.
The long growing season of tomatoes means that you need to start early if you want to grow tomato plants from seeds and harvest tomatoes in the fall. You can sow tomato seeds indoors as early as February – a growing lamp will help if the light levels are very low.
Sow from late March to early April if you intend on growing your tomato plants outdoors.
Check the last frost dates for your region and sow your seeds around 6-8 weeks before the estimated date to get the timing right. Check the variety of your tomato plants and label them so you know how long they should take to mature, and their size at maturity.
Seedlings need care and attention to grow successfully, with frequent light watering, access to as much light as possible, and good air circulation. Unidirectional light can cause seedlings to become “leggy”, or stretched out with an elongated stem as they strive to get enough light to grow.
When outdoor temperatures have started to rise in spring, you can start hardening off your young tomato plants by putting them outdoors (in their pots) on sunny days for a few hours at a time, so they can slowly adjust to life outdoors.
It might be tempting to skip hardening off, but it’s worth it if you can muster the patience. Plants that adjust slowly to outdoor conditions are usually hardier, with thicker stems, more vigorous foliage growth, and stronger roots.
The first of May is usually considered a certain safe date from further frost, and so if your plants are looking good, you can plant them out in your garden.
Indeterminate tomato plants will grow as tall as they can, so you should stake them to support their vertical growth.
Once your young tomato plants have started to flower, it’s a good idea to give them a weekly feed using a solution of diluted liquid tomato fertilizer.
Check the variety of tomatoes and the color the tomatoes should be – it could be a green tomato variety
This might seem obvious, but it’s worth checking your seed packets to make sure that the variety of tomato you are growing isn’t simply a green tomato! There are many varieties of green tomatoes, such as Green Giant, Cherokee Green, Green Zebra, Evergreen, and Aunt Rubys German Green. They are usually heirloom varieties, which are pollinated naturally and selected by farmers for their flavor. These green tomato varieties do ripen, but they don’t change color. You can tell they are ripe by giving them a gentle squeeze – if they are soft, they are probably ready to harvest.
Both unripe green tomatoes and ripe green tomatoes can be used in a variety of recipes! Fried green tomatoes are a part of Southern food culture in the USA, and you can use unripe green tomatoes or ripe green tomatoes for these recipes. Green tomato varieties can be as tasty as red tomato varieties, and they can be fun to grow alongside your regular red tomatoes.
How do you ripen late-season green tomatoes?
The weather is hard to predict, especially with climate change affecting us more and more, and often things don’t go as planned when it comes to growing tomatoes. In a perfect growing year, we’d have sown our tomato seeds between February (indoors) and early April (plants for outdoors), have our first tomato harvest in summer (usually July), and each tomato plant would continue to produce tomatoes even into October.
However, bad weather can cause heat-loving plants to get off to a slow start, and growth can be delayed. If the timing is off, you’ll likely still have some green tomatoes on the vine towards the end of the season.
If your tomato plants are in pots, simply bring them indoors so that the fruits can continue ripening in a sheltered environment.
If your plants are in your garden, or they’re in pots outdoors and you cannot bring them indoors, you can try using a blanket or row covers to insulate them from the cold at night. You’ll need to do this every day, but it’s worth a try if you don’t have other options.
Tomato plants that are in your garden or allotment are trickier. The best option for ripening these late-season green tomatoes is to remove tomatoes from the plant and ripen them indoors, especially if the weather is starting to turn colder and wetter.
Leaving tomatoes on the vine late into harvest time can be risky as they are more susceptible to late blight. Blight is a disease caused by a fungus-type organism that quickly spreads between tomato plants, causing them to rot and die. Blight is the bane of the tomato gardener’s existence, as it is almost impossible to stop once it sets in.
How do I know if my tomato plants have blight?
Small brown marks will start to appear on the leaves of tomatoes plants with blight, with the brown areas growing larger as the blight spreads. Brown spots will appear on the stems, and these spots will soon turn black and mushy. Finally, the fruit will be affected, and the leaves will shrivel up and fall off.
What causes tomato blight? The disease-causing organisms are soil-borne, and when rain or watering causes wet soil to splash onto the stem and leaves of your plants, these fungal organisms can start to damage the plants.
How to deal with tomato blight
Once you notice tomato blight on your tomato plants, it’s essential to act quickly. Remove any damaged leaves, pull out every sick plant, and destroy the affected material. It’s best to burn material affected by tomato blight instead of composting it to reduce the risk of it spreading.
How to avoid tomato blight
Choose tomato varieties that are specifically bred to have resistance to blight.
Water your tomato plants at the roots, taking care not to splash the stem and lower leaves with too much water. Watering from above can cause fungal growth if excess water cannot evaporate quickly enough, so try to avoid this.
Maximize ventilation! Ensure that there is enough space between plants in your garden or greenhouse, and trim excess foliage from the bottom of your plants.
If you are growing tomatoes indoors, open windows and try to get as much airflow as possible.
You may also like this article: My tomatoes are splitting, how can I stop it?
How do you ripen green tomatoes off the vine?
Sometimes it’s necessary to remove tomatoes from your tomato plants. If it’s nearing the end of the season and your tomato plants are dying off, if pests are damaging your fruit, or if the weather is wetter and colder than expected, you might want to save your remaining fruit and ripen your tomatoes indoors.
Tomatoes are climacteric fruits, which means that they continue to ripen after harvest. Thankfully, this means that they can be harvested when still mostly green as long as the fruit is mature. Can I ripen green tomatoes in the house? Yes!
Here are some helpful tips to show you how you can do it:
Leave a bit of the stem on when you pick your green tomatoes
Tomatoes ripen most successfully when a small bit of the stem is left intact. Use a pair of secateurs or a sharp pair of scissors to remove your tomatoes from the plant. You can remove them individually or together as a set.
Wash and dry your tomatoes carefully after picking them
Cleaning your tomatoes removes any fungal spores or pests that might damage them as they ripen. Be sure to dry them thoroughly to discourage mold from growing on them. Remove any damaged tomatoes from the rest, as they could start to decay and spoil the rest.
Put your unripe tomatoes in a paper bag
The goal of this method is to trap the ethylene gas in a small space with your unripe tomatoes so that it speeds up the ripening process. As the ripening tomatoes release the gas, the ethylene will stay in the paper bag and stimulate even more ethylene production from other tomatoes.
For faster results, you can add a ripe banana or an apple to your paper bag of tomatoes, as these fruits release ethylene too (all fruits do when ripening, in fact).
Put green tomatoes indoors in a cardboard box
Line the bottom of a cardboard box with newspaper, and place your tomatoes stem down (blossom end up) in a single layer in the box. The green tomatoes will ripen in a few days. Check on them every day, and make sure that you remove any tomatoes that start to spoil. This method can also be used to store ripe tomatoes, as the cardboard box allows for some airflow and allows moisture to evaporate.
Ripen green tomatoes on a windowsill
You can ripen green tomatoes on a warm windowsill if they already have a bit of color on them, but try to keep them out of direct sunlight to prevent the skins from toughening up. This method of ripening is good for keeping an eye on your tomatoes as they ripen, as they are visible and hard to forget about.
Hang the entire plant upside down indoors
The idea behind this ripening method is that by keeping the tomatoes attached to the plant, they will continue to draw energy from it and this will help the tomatoes to ripen.
Remove the plant from the ground carefully, and shake as much soil from the roots as you can. Then, tie a string around the roots, and hang it in a cool, dry place such as a basement or a garage.
This method is quite messy, so you might need to lay down some newspaper underneath your upside-down plants to catch falling soil.
Check on your plants frequently and remove tomatoes once they have ripened (and before they splat onto the floor!).
Common myths about growing and ripening tomatoes
There is an overwhelming amount of information out there about the best way to grow tomatoes and how to ripen them. Of course, some methods may work in some climates and for some growers, but not all miracle methods are foolproof.
“Tomatoes ripened on the vine always taste better”
In fact, there’s no evidence that vine-ripened tomatoes actually have a superior flavor to tomatoes that are ripened off the vine. Of course, the idea of tomatoes ripening on the vine on a sun-drenched summer day is lovely, and perhaps these thoughts influence our experiences. The taste of a tomato is based on its variety and its genetics, and how it’s stored and cooked.
“Pinch out side-shoots (suckers) on your tomato plant to encourage fruit production”
Removing side-shoots is often recommended, but it’s not been definitively proven to increase the yield of fruit in a significant way. One benefit to removing side shoots is to increase airflow around the plant, which reduces the risk of fungal infections such as blight.
Side shoots actually create more flowers which will turn into tomatoes, so they can be worth keeping. However, if your plant is producing fruit slowly and they are taking ages to turn red, you might want to remove the suckers because they probably won’t create mature tomatoes before the weather turns in October.
“Remove foliage from your tomato plant so the fruit has direct sunlight”
You don’t need direct sunlight to ripen tomatoes, you just need enough warmth for ripening. Some gardeners may remove foliage so that each tomato gets direct sunlight, but if the sunlight is too strong, it can cause damage by sun scorch.
Tomato glut? How to store and preserve your ripe tomatoes
If all goes well, you will hopefully be swimming in tomatoes by October, perhaps far too many than you could possibly eat! If this happens, you can preserve extra tomatoes by canning them or making jams and chutneys with them.
How to make sweet tomato jam with your surplus ripe tomatoes
Use up your extra tomatoes by making a delicious jam with them! This jam isn’t canned, so it can be made quickly and easily and stored in the refrigerator.
- 2 pounds ripe cherry tomatoes
- 3/4 cup brown sugar
- 2 tbsp apple cider vinegar
- 1 tbsp fresh grated or minced ginger
- 1/4 tsp ground cinnamon
- 1 pinch ground cloves
- 1 tsp salt
- 1/2 tsp cayenne pepper
How to make this recipe:
Add all of the ingredients to a large saucepan and bring to a boil, stirring frequently. When it’s reached boiling point, reduce the heat and simmer, stirring every now and then, until the mixture reaches the consistency of jam. Let your jam cool, and store it in an airtight container in the refrigerator.
Enjoy with cheese and crackers, sandwiches, or avocado toast.
Best of luck in your tomato growing endeavors, and may your green tomatoes always turn red!