Growing tomatoes can be incredibly rewarding, but sometimes they just don’t turn red like you expect. If you’ve been diligent about watering, fertilising, and managing diseases, it can be frustrating to see green tomatoes that refuse to ripen.

Here’s a simple guide on why this happens and how to help your tomatoes turn red.

Common reasons tomatoes aren’t ripening

1. Temperature

Weather is a major factor in tomato ripening. Tomatoes ripen best between 20-25°C. When temperatures soar above 29°C, tomatoes stop producing the pigments that turn them red. If it’s too hot for a long time, your tomatoes might stay yellowish-green or orange. Unfortunately, there’s not much you can do about the weather except wait for cooler temperatures.

2. Too much nitrogen

While fertilising is important, too much nitrogen can be a problem. Excess nitrogen promotes leaf growth at the expense of fruit ripening. After your tomatoes start setting fruit, reduce the amount of fertiliser. Usually, fertilising two or three times a season is enough.

Why tomatoes aren't ripening


3. Too many fruits

Sometimes, a tomato plant has too many fruits developing at once, which can slow down ripening. If this happens, try removing about a fourth of the fruits. This helps the plant focus its energy on ripening the remaining tomatoes.

4. Type of tomato

Different tomato varieties ripen at different rates. For example, cherry tomatoes ripen faster than large heirloom varieties. Sometimes, all you need is a little patience.

How to ripen green tomatoes after harvesting

As the weather cools in fall and temperatures drop below 10°C, tomatoes will stop ripening on the vine. But there are ways to ripen them indoors:

Harvest partially ripened tomatoes: Pick tomatoes that have started to change colour and feel slightly soft. Place them in a room with temperatures between 15-18°C, like a pantry or basement.

Use a paper bag: Place your tomatoes in a paper bag with an apple or banana. These fruits release ethylene gas, which helps tomatoes ripen faster.

Why tomatoes aren't ripening


Hang the whole plant: If you have a lot of green tomatoes, try uprooting the whole plant and hanging it upside down indoors. The tomatoes can ripen on the vine as the plant dies.

Bring potted plants indoors: If your tomatoes are in containers, bring the whole pot inside and place it in a sunny spot. This can help the last fruits ripen.

By understanding these factors and following these tips, you can enjoy ripe, red tomatoes even if they need a little extra help.


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