Why don't tomatoes turn red? If your tomato plant has green fruit hanging on it, it may be a sign that the temperature and soil conditions are not ideal. Whether in the greenhouse or in the garden, with a few tricks you can get the fruit to change color on the plant or after harvest.
Tomatoes are one of the most popular vegetables grown in the kitchen garden. Even if you have been growing tomatoes for many years, it may happen that the conditions are not right and the fruits do not ripen. You observe the large, shiny green fruits on the bush, but they do not ripen for weeks. Luckily, there are some ways to speed up the ripening process and save your tomato crop.
Your tomato plants are showing lots of healthy growth, but their fruit remains green and does not ripen. This can be a frustrating problem for any gardener, but don't worry. It can be fixed if you act quickly. Below we've summarized the most common reasons why tomatoes don't turn red and what you can do about it this season.
When are they actually supposed to turn red?
The ripening time of tomatoes depends on various factors such as the specific variety and weather conditions. This is because larger tomatoes take longer to reach the green ripeness stage required for later red coloring.
In general, tomatoes should turn red around 6 to 8 weeks after the flowers have been pollinated and the first ripe tomatoes should be harvested from the end of July.
Temperatures too high
One of themost common causesThe reason tomatoes don't turn red is because the temperatures are too high.
At temperatures above 32-35 °C, the ripening process slows down significantly or even stops. If the temperature is too warm, the fruit on the stem will look either greenish-orange or pale green. The pigments lycopene and carotene, which give the fruits their typical red appearance, cannot be formed at these temperatures.
Very high temperatures can alsoyellow leaves on your tomato plantscause.
There's not much you can do in this case except wait until the temperatures drop again and the ripening process starts again.
Low temperatures affect ripening
The ideal temperature for a tomato is between 20°C and 25°C. If night temperatures are below 10°C or daytime temperatures are below 15°C for two weeks, this can also affect tomatoes' redness. If this is the case, the tomato fruits will not only be green, but also soft and misshapen.
The tomato plant is overgrown
When tomato plants grow too much, they put too much energy into new growth instead of ripening the fruit. Pruning tomato plants can help the plant produce lots of healthy fruit.
Before moving the young plants outdoors, remove any lower branches to plant them deeper and encourage new root growth. Also prune lower shoots later in the season that are not producing flowers to encourage fruiting. Check the growth of tomatoes regularly and keep the plants at an appropriate size.
Too many fruits at once can also be the reason why tomatoes stay green. If the plant bears too many fruits at once that cannot ripen for a long time, you should remove a quarter of them. This will help the plant focus its energy and resources on the remaining fruit.
Why don't tomatoes turn red? Overfertilization with nitrogen
You may end up over-fertilizing your tomatoes if you use a product that is high in nitrogen. This can encourage plants to put their energy into producing leaves rather than turning the green fruits red. The flowers may fall off, and the fruits that form remain green for a long time.
When the plants begin to flower, use a natural fertilizer high in phosphorus and potassium for the fruiting phase. Once the plants begin to bear fruit, stop fertilizing.
A green tomato variety
Sometimes it seems like a tomato takes too long to turn red, but that may depend on the variety. There are many varieties that do not turn red even when ripe and remain green or yellow. When trying a new tomato variety, the first thing you should do is find out what the ripe fruit looks like.
How can you promote ripening on the stem?
If you already have themost common causesKnowing why tomatoes don't turn red, there are some measures you can take to encourage ripening on the stem and save your crop.
- Shade the tomatoes:If it gets too hot during the day, you should cover the plants with shade cloth to prevent the fruit from becoming too hot.
- Protect from low temperatures:Use polytunnels or garden fleece to protect the tomatoes from temperature fluctuations. Make sure to open the polytunnel during the day and remove the garden fleece so that the flowers can be pollinated.
- Shorten the main shoot:Cut off the main stem if your tomatoes don't ripen. This forces the plant to no longer waste its energy on growing new leaves and forming new fruits, but on ripening green tomatoes.
- Strain tomatoes:Stingy shoots are the smaller stems that form between the skin shoot and a lateral fruiting shoot. Remove any shoots on your plant to channel their full power into the fruit and promote ripening.
- Remove flowers in late summer:If your tomatoes continue to bloom in late summer, remove those flowers that don't have time to develop to conserve the plant energy they use.
- Stop fertilizing in good time:Once the tomato plants are established and large enough to bear fruit, stop fertilizing.
- Reduce watering:A continuous supply of water throughout its lifespan makes the plant believe it has plenty of time before the fruit is harvested. If the fruits are large enough but do not turn red, reduce the amount of water available to the plant. This directs the plant's energy into maturing rather than using the moisture for new growth.
Can green tomatoes ripen?
Ideally, the tomatoes should ripen on the stalk. However, when the first frost is approaching, you can pick all the green tomatoes and let them ripen at room temperature. They release their own ethylene gas to promote ripening. If you want to speed up the process even further, store them with an apple or ripe banana.
Another method is to pull up the entire tomato plant and hang it upside down in a sunny spot or warm room. Make sure some roots are still in place and avoid direct sunlight.
If you are growing your tomatoes in containers, you can simply bring them indoors where it is warmer so they will ripen faster.
Use green tomatoes
Even if your tomatoes don't turn red, you can still eat the green fruit. There aremany delicious recipesthat you can use to utilize them.
And whatever you do, never store your ripening tomatoes in the refrigerator. You want them to turn red at room temperature, otherwise they will lose their unique tomato flavor.
In which cases tomatoes are poisonous,find out here.
