How To Ripen Tomatoes

As we approach the end of the tomato growing season there are always a few trusses of unripe or green tomatoes left on the plant. Here is our guide on how to ripen green tomatoes:

Preparing Tomato Plants to Ripen Fruit

To encourage tomatoes to develop and ripen on the vine prior to harvest there are a few simple steps you can take to prepare the plant:

1. Trim off excess foliage around fruits. This exposes the tomatoes to light to increase melatonin production to promotes ripening. ¹
2. Remove lower leaves to increases airflow around the plant which will minimise the risk of late blight appearing whilst the fruit develops.²
3. Remove any last flowers that are unlikely to develop usable fruits.
4. Remove any small or diseased fruits.
5. Cut off the growing stem at the top, to discourage energy being put into producing new leaves and flowers. You may need to repeat this process if the plant keeps pushing out new side shoots.

When to Harvest Green Tomatoes

There is no exact science as to the best time to harvest any remaining tomatoes, as it depends upon weather and conditions in your location, however, you may want to consider:

1. Leaving the tomatoes exposed to too much sun can cause the skins to toughen.
2. As the temperature drops and the chance of frosts approach you risk damage to the plant or fruits.
3. As the plants get older, the chances of late tomato blight increase.

The exact timing to bring remaining tomatoes inside will vary depending upon weather conditions and location, however, in general this tends to be September to October.

If you still have some green tomatoes at this stage, you can easily ripen them off indoors.

How to Ripen Tomatoes Indoors

Once you have collected your remaining green and unripe tomatoes, here is how to ripen them off indoors:

1. If you have tomatoes that are nearly ripe, but just need to develop a little, we recommend placing them in a fruit bowl in the kitchen.
2. Resist placing unripe tomatoes on a window sill or other overly sunny spot as the continued exposure to the sun could toughen the skins, cause uneven ripening and reduce shelf life. ³
3. The fridge isn’t the best place either as the low temperature could hamper ripening.
4. Tomatoes, much like bananas, avocados and many other fruits, produce their own ethylene gas which helps the fruits ripen. ⁴ Commercial growers routinely use Ethylene gas to promote or control ripening of tomatoes, ⁵ however, such forced ripening of tomatoes may turn the fruits red but doesn’t necessarily allow the fruit to develop the natural sweetness and flavour of a home-grown tomato.
5. We recommend placing the tomatoes in an unsealed container or bag, in a cool, dry location. The container should be unsealed to allow the fruit to breathe but closed enough so as not to allow the ethylene to immediately disappear. This should allow the fruit to ripen in around one to two weeks.
6. To speed up the ripening process, you could try adding a ripe banana to the bag or container as a ripe banana will give off more ethylene.
7. Check the tomatoes from time to time to remove ripened fruit and check none are going bad.

Finally, if you are left with any green tomatoes, you could make some delicious Green Tomato Chutney.

1. Shuya Wang, Ning Jin, Li Jin and others – Response of Tomato Fruit Quality Depends on Period of LED Supplementary Light – doi: 10.3389/fnut.2022.833723
2. Choriyev Elbek Abdusattorovich, & Shomirzoyev Asliddin Avazovich. (2022). Tomato Plant Diseases and how to Control Them. International Journal of Life Science and Agriculture Research, 1(1), 08–10. Retrieved from http://ijlsar.org/index.php/ijlsar/article/view/4
3. Vera Thole – Effect of Elevated Temperature on Tomato Post-Harvest Properties – doi: 10.3390/plants10112359
4. M B Etana – Samara University, College of Dry-land Agriculture, Department of Horticulture – Review on the effects of ethylene (C2H4) on quality of fresh fruit and vegetable. The case of banana and tomato
5. Mikal E. Saltveit – Effect of ethylene on quality of fresh fruits and vegetables – doi: 10.1016/S0925-5214(98)00091