Why tomatoes crack when ripening in a greenhouse: we identify the cause and effectively fight it
The world's largest tomato was grown in 2016 in the USA and weighed 3.9 kg. True, this giant tomato was all covered with cracks, which is not surprising, given its size.
In our country, tomatoes do not grow to such sizes, but when grown in greenhouses, you can get an excellent harvest. However, the process of fruit ripening is often marred by the same problem as the giant American tomato - the appearance of cracks in the tomato skin. In this article we will tell you in detail why tomatoes crack when ripening in a greenhouse and about methods to combat cracking.
Cracked tomatoes - how dangerous is it?
When the harvest ripens in the greenhouse, you can often find fruits with cracked skin on the bushes. And if the tomatoes are planned to be immediately eaten (or processed), then this is not critical.
Moreover, if the infection or mold fungi do not immediately penetrate inside the tomatoes, the crack is closed with cork fabric and the crop can be stored in this form for several days.
But when grown for sale, bursting vegetables become a problem: their shelf life is reduced and their presentation is spoiled. When fungi and bacteria enter through cracks, the red-pink and yellow fruits become unfit for consumption.
Reasons for the appearance of cracks in tomatoes in a greenhouse
The main causes of cracks are improper growing conditions. Let's look at each of the reasons in detail.
Irregular and too much watering
Most often, greenhouse tomatoes burst due to irregular watering.
Remaining in dry soil, vegetables slow down their growth, and their skin loses elasticity. And if after a week's break you start watering abundantly, this will cause intensive fruit growth. The skin, unable to withstand the pressure from the inside, bursts. This can happen not only on ripe vegetables, but also on green ones.
The same thing happens if there is plenty water the beds in the heat, pouring the entire volume of water under the root at once.
Excessive pinching of shoots and tearing of leaves
Knowing the benefits stepsons, some gardeners get too carried away with it. But the fact is that the roots consume water from the ground in accordance with the volume of green mass of the entire plant. And after removing a large number of shoots and leaves, excess moisture can only enter the fruits.
The smaller the side branches and leaves of a tomato bush become, the more water accumulates in the fruits, causing their rapid growth. In this case, the skin does not keep up with the growth of the fruit and bursts.
The same thing happens if you overdo it with pinching the top of the bush during the ripening of the crop. The total area of moisture evaporation is significantly reduced, the fruits quickly become filled, and cracks form on their surface.
Tomato diseases
These juicy vegetables sometimes crack due to diseases that appear during ripening. As a result of the damage, the tomatoes not only burst, but also become unfit for consumption.
The most dangerous for the outer shell of the fruits of this crop are: Alternaria or dry spotting, blossom end rot, late blight. The causes of diseases in greenhouses are insufficient ventilation and excessively high air humidity.
Systemic fungicides, special microbiological preparations (for example, Fitosporin) and combined fungicides (such as Ridomil Gold MC) will help correct the situation.
But the most effective disease prevention is constant daytime ventilation, removal of lower leaves, reducing air humidity in the greenhouse, and preventive spraying with drugs.
Unsuitable temperature or changes in temperature
Unfavorable temperature conditions for growing tomatoes often lead to bursting fruits.
In hot weather, the temperature in the greenhouse can rise to a critical level for tomato bushes (40 °C and above). Heat makes the tomato skin rougher, more inelastic, and when the growth of the fruit accelerates, its outer shell ruptures.
The sharp contrast between day and night temperatures has a negative effect on the integrity of tomato peels.
Wrong choice of variety
Ultra-early ripening hybrids with delicate pulp and thin skin are most susceptible to cracking. This problem is especially common with yellow and pink tomato varieties. Tomatoes of large-fruited varieties often burst (regardless of their color).
Errors when applying fertilizers
Often, the tomato crop begins to crack in greenhouse beds due to improper or untimely application of fertilizers.
Cracking is promoted by excess nitrogen or the application of concentrated fertilizers. The skin of the fruit also bursts when there is a lack of essential microelements.
Attention! Using concentrates will cause cracks in the outer skin of the tomatoes.
Why are cracks dangerous?
Cracked skins on tender vegetables can cause much of the crop to spoil. Fungi and bacteria easily penetrate into bursting fruits, the process of rotting begins, and all the work of the vegetable grower goes down the drain.
In addition, cracked tomatoes have a much shorter shelf life than whole fruits. If the integrity of the shell is damaged due to diseases, such fruits are dangerous to eat.
Tomato varieties that are not prone to cracking
When choosing tomato varieties for your plot, pay attention to those that are easier to tolerate permissible errors in care. There are many varieties for growing in a greenhouse that are not prone to breaking the fruit shell.
Most of them are late ripening or hybrids:
- Bohemia F1 is a hybrid with strong fruits that tolerates long-term transportation.
- Asteroid – a variety highly resistant to diseases. The fruits are large, and the dense peel is less susceptible to tearing.
- Centaur – a hybrid of large size and resistance to major diseases.
- Raspberry Viscount – a low-growing variety that is unpretentious to growing conditions, suitable for long-term storage.
- Our Masha – this variety is well adapted to extreme weather conditions.
- Vladimir F1 is a hybrid with long-lasting fruits. Resistant to cracking.
- Khutorskoy salting – late-ripening medium-sized variety, the harvest is well stored.
- Boomerang – a hybrid that ripens in 90-105 days and withstands transportation well.
- Miracle – a variety resistant to temperature changes and wet weather. Unpretentious, productive and disease resistant.
Ways to solve the problem of cracking
If you notice bursting tomatoes in your greenhouse, you can use the simple steps below to prevent further damage to the fruit.
Preventive spraying against fungal diseases
Already at the seedling stage, it is necessary to prevent fungal damage to plants in the greenhouse.
Tomato bushes are treated with a solution of “Fitosporin-M”: for spraying, take 5 g of powder and dilute it in 10 liters of water. The procedure is repeated once every ten days.
Creating the necessary microclimate in the greenhouse
To create a microclimate suitable for a fastidious crop, the greenhouse is always ventilated during the day and closed at night. This will prevent sudden changes in temperature.
In hot weather, open all windows and doors for better ventilation and cooling of the air in the greenhouse. Optimal temperature conditions: + 20... +28 °C during the day and +16... +18 °C at night.
External application of lime milk to the walls and roof of the greenhouse helps delicate plants avoid overheating.
Experienced gardeners also maintain a suitable level of air humidity (55-65%). If the humidity is higher, constant ventilation throughout the day will help reduce it.
If the air humidity in a greenhouse is significantly higher than normal, tomatoes are inevitably affected by fungal diseases.
Removing leaves and pinching bushes
The yield largely depends on how the bush is formed.
You should not pick off too many leaves, because without them the balance of moisture and nutrients in the ripening crop will be disrupted, and cracks will appear.
The leaves are removed for the first time 2 weeks after planting the seedlings in the greenhouse. First of all, remove the leaves that touch the ground (they can cause diseases in the plant).
Moreover, foliage should be removed gradually - no more than 2-3 leaves per week on each tomato bush.
Pinching is the removal of not side shoots, but the top of the bush, in order to limit the growth of the fruiting stem in height. Thanks to this technique, the fruits ripen faster and burst less.
Important! The top is pinched only after the flowers of the upper inflorescence have opened, i.e. from the second half of July. In this case, several leaves must be left above the upper inflorescence - with their help, the fruits will receive nutrients.
Timely planting of tomatoes
Almost all varieties of tomatoes require removal of shoots. This way you help your bushes direct all the juices to ripening vegetables.
It is optimal to start the procedure after the first stepson appears under the first flower brush. Don't wait until it grows more than 5 cm in length, otherwise it will have time to draw on precious food.
Stepping is carried out in the morning, in dry and warm weather. The optimal frequency for removing stepchildren is once every 7-10 days.
Fertilizer application and feeding
To prevent cracking of tomato fruits, experienced vegetable growers strictly follow the instructions for diluting fertilizers. To feed greenhouse bushes, it is enough to dilute the fertilizer in a ratio of 20 g per 10 liters of water.
Tears may appear on the skin of tomatoes both when there is a deficiency or excess in the soil of microelements and macroelements.
The feeding scheme for tomato bushes includes the following steps:
- Even before planting tomato seedlings, greenhouse beds must be saturated with fertilizers (nitrogen, potassium and phosphorus).
- Two weeks after planting, the bushes are fed with three main elements: nitrogen, phosphorus and potassium, as well as microelements.
- During the period of active growth, it is useful to fertilize the greenhouse crop with nitrogen and phosphorus.
- During flowering of tomato bushes, it is advisable to add potassium and phosphorus to the soil (nitrogen is not needed at this stage).
- During the period of fruit set, it makes sense to feed the plants again with potassium and phosphorus.
- The last fertilizing is carried out 2 weeks before harvesting (potassium, manganese, boron, iodine).
Moderate and regular watering
Optimal in hot weather water the tomato bushes twice a week in the evening. This will help avoid accelerated growth and cracking in the tomatoes.
In cloudy weather, it is enough to water the greenhouse beds no more than once every five days. When the night temperature drops below 13 °C, it is more advisable to postpone watering to 11-12 o'clock in the afternoon.
When watering, you cannot immediately pour out the entire required volume of water under the bushes - you need to moisten the soil in several steps, waiting for each portion of water to be absorbed.
The greenhouse crop is detrimentally affected by water getting on the leaves. Therefore, water the bushes at the root with warm water (temperature 22-25 °C).
Stopping fertilizing during the ripening period of tomatoes
Many gardeners are of the opinion that you should not “stuff” vegetables with fertilizers on the eve of harvest. By this time, the tomato fruits have already received all the necessary nutrients, so another feeding threatens an overdose of elements and cracking.
How to prevent tomatoes from cracking in a greenhouse - tips and tricks
Below is a list of measures you can take to prevent the problem of bursting tomatoes.
- Choose varieties that are resistant to cracking.
- After planting the seedlings, water regularly and evenly.
- Maintain an optimal microclimate in the greenhouse (temperature, air humidity, ventilation).
- Do not forget to carry out preventive spraying against fungal diseases.
- Perform pinching in a timely manner, but do not get carried away with tearing off the green mass.
- Take measures to prevent diseases of tomato bushes.
- Apply the necessary fertilizing once every two weeks.
If, when all the above conditions are met, the tomato crop continues to disappoint with many bursting fruits, it is recommended to analyze the mineral composition of the greenhouse soil.
Conclusion
To ensure that your tomatoes remain smooth and beautiful until harvest, it is extremely important to maintain an acceptable microclimate for them, water them regularly, thoughtfully form the bushes, feed and spray them.