The nicer the summer, the earlier tomatoes can be harvested. If the conditions are not optimal, it can happen that tomato plants still bear a lot of green, unripe fruit in late summer and autumn. Due to the cooler temperatures, these fruits no longer turn red. If you don't help now and help the fruit ripen, part of the tomato harvest will be lost. The post-ripening can be done in different ways without much effort.
Let the tomatoes ripen
harvest time
Don't wait too long to harvest
You should not wait too long to harvest unripe fruits, because even the smallest ones below zero would let them perish. If the temperatures drop below 10 degrees, the fruits outside no longer turn red or yellow, depending on the variety. The cold night dew can already cause damage to the tomato skin in the form of glassy spots and cause them to rot.
Consequently, it is advisable to harvest before temperatures drop permanently below 10 degrees. Depending on the space available, you can harvest the individual fruits, cut off entire panicles or pull the entire plant including the fruit out of the ground and let the tomatoes ripen on the plant.
If you harvest individual fruits, you should not tear them off the bush, but cut them off together with the stalk. The tearing can damage the fruit, which in turn encourages germs to enter. The stalk should generally remain on the fruit. It provides the intensive aroma during the maturing process.
tip: Fruits that have bruises, cracks or other damage are no longer suitable for ripening. Only intact fruit should be used for this.
Optimum conditions for ripening
- Tomatoes need heat and high humidity to ripen
- Tire temperatures between 16 °C and 25 °C
- Optimal is 18-20 °C
- The cooler it is, the longer it takes to fully ripen
- The ripening process can then drag on until December/January
- With sufficient heat and humidity, it can take up to three weeks
- Relative humidity of more than 80 percent is ideal
Light can be completely dispensed with. As long as tomatoes are growing, producing fruit and seeds, they also need sufficient light. As soon as they are fully grown, they can cope with significantly less light, because light is not absolutely necessary for the typical red colouration.
Methods and Procedure
In clay pots
In clay pots such as B. a Roman pot or an oriental clay pot (tajine), the tomato should ripen particularly quickly and gently. Before the pot can be filled, it must be cleaned thoroughly. Then put it in the water for a few hours.
Then you layer the dried fruits in the clay pot and cover it with a clay lid if possible. The coaster is filled with water and refilled as soon as the water has evaporated. The whole thing is then placed in a suitably warm and humid place. It won't be long before the first tomatoes are red and taste like they've ripened in the sun.
In boxes or cartons
With larger quantities of fruit, you can also use crates, cartons or baskets in which to stack the unripe tomatoes.
- Line crates or boxes with newspaper first
- Lay the loose fruit or tomato stalks next to each other on top
- Only use healthy and undamaged fruit
- For larger quantities, place the fruit in two layers on top of each other
- Cover the first layer with several layers of newspaper beforehand
- Then lay out the second layer of fruit
- It shouldn't be more than two layers
- Finally, cover the second layer with paper as well
- Place boxes in a warm, dark, and humid place
From now on, the tomatoes should be checked daily for rot or mold and discarded any diseased or damaged ones. If you want to speed up the ripening process a little, you can put an apple, pear or banana in the box with the tomatoes. The ethylene contained in this fruit allows unripe tomatoes to ripen faster.
tip: Frequently, fruit whose ripening process has been accelerated with ethylene spoils more quickly, although they also produce the gas themselves. For this reason, ethylene-sensitive foods should not be stored or stored near apples.
Using a cold frame or cold box
If the weather conditions allow it and the outside temperature does not fall below 12 °C, unripe tomatoes can also be left to ripen in a cold frame or cold box. First you need a solid base such. B. a wooden board. This is to prevent the fruit from touching the ground and rotting.
The board is placed next to or in front of the plant and folded over so that the tomatoes lie on the board. Now you put a cold frame or cold box over the fruit and cover the whole thing with an insulating and opaque fleece or a warming foil. In this way, these fruits can also ripen in a greenhouse.
Leave to ripen on the plant
Green, unripe fruits can also ripen very well on the plant, provided there is enough space available. To do this, pull the entire plant including the root out of the ground or cut it off close to the ground. Then remove the leaves, otherwise the tomatoes may become shriveled. Now hang the plants upside down in a warm, humid place. This can be a dark attic, basement or a similarly dark room with high humidity. Here, too, it is important to ensure that all fruits are undamaged.
Green, unripe fruits are poisonous
Unripe, green tomatoes are left to ripen in order to reduce unwanted substances in the fruit and to bring them to full ripeness. What one should never do is eat unripe green fruits, because they are poisonous. This is due to the substance solanine, which is also known from green potatoes.
- Solanine is found in high concentrations in unripe fruit
- Solanine in this concentration is hazardous to health
- Contains between 9 and 32 milligrams of solanine per 100 g of fruit
- From a dose of 25 milligrams, this active ingredient is considered toxic
- From a dose of 400 milligrams, this natural toxin is deadly
- Solanine is fat-insoluble and heat-stable
- Toxicity therefore remains even when cooked
The first signs of poisoning can occur with an intake of 200 milligrams or more. It can cause a sore throat, nausea and vomiting, as well as gastrointestinal problems, headaches, drowsiness, tenderness to the touch, and breathing problems. At even higher doses, body aches, kidney and intestinal inflammation as well as cardiac arrhythmias and signs of paralysis are possible. During the ripening process, the concentration of the toxin in the fruit decreases. They still contain solanine, but in such a low concentration that it is no longer a health hazard.
tip: One should not confuse unripe green tomatoes with green-fleshed varieties, which are slightly yellow-green when fully ripe. They also contain large amounts of solanine when unripe and are poisonous.
notice: Please note that this article is by no means a substitute for a doctor's visit. There is no guarantee of the correctness of medical statements.
Detailed information on first aid in the event of poisoning and important information on the poison control centers can be found here.