The time for planting tomato seedlings for a greenhouse is difficult to calculate in advance, especially if the greenhouse is cold and spring weather is unstable, which is typical for both temperate and cold latitudes. In any case, the future harvest should be protected from the influence of weather changes by choosing the right cold-resistant variety and properly preparing and replanting young seedlings.
Choosing the right seeds for greenhouses
Correctly selected tomato seeds dictate the entire future harvest. Varieties with a long growing season or with long vines that significantly exceed the height of the greenhouse are not suitable for greenhouses.. For seedlings intended to be grown indoors, it is important to have the ability to self-pollinate and have sufficient resistance to diseases associated with high humidity levels, therefore, we sow only varieties intended specifically for indoor soil. Also important is the high yield of each individual bush and the possibility of repeated harvesting - preferably until late autumn. You need to read information about the fruiting of a variety before growing tomatoes. All information on how to sow tomatoes of this type and how long it will take to harvest the future harvest is located on the packaging with planting material.
Seeds prepared independently during one of the previous harvests must gain strength for at least one year - they can only be planted after missing one or two summer seasons. It is important to remember that for sowing material for seedlings, only pure and not mixed varieties are used. Not a single experienced gardener sows seeds that he inherited from unknown varieties or, if there is a suspicion that the tomatoes once sown are a hybrid species.
When to sow seeds for seedlings
The time when tomato seeds can be sown is calculated based on several factors:
- characteristics of the greenhouse (insulated, cold);
- forecasts for spring (whether late frosts are expected);
- the ability to germinate seeds at home (or the need to immediately sow tomatoes in closed ground).
Simple mathematical calculations come into force, helping to determine the timing of planting at a particular latitude. So, from the moment of sowing a tomato seed until the day planting tomato seedlings in a greenhouse, two months will pass (55-65 days). By the end of this period, certain conditions must be met - the daytime temperature in the greenhouse should not fall below 24 0C, night - stay within 17 0C. In a heated greenhouse, such conditions are not difficult to achieve, so the timing of planting seedlings will not be limited by any time of year.
Having a simple summer cottage greenhouse without heating, the gardener must be prepared for the fact that half of the growing season, tomato seedlings will be heated at home. In some cases, seedlings are planted in a permanent place no earlier than the 20th of May. However, even in the best case scenario, with good stable weather and sufficient humidity, the transfer of tomato seedlings to a “cold” type greenhouse will occur only on the first days of the last spring month (approximately May 3-5).
Taking into account all the above factors, we can approximately determine the optimal period when to plant tomatoes as seedlings. For middle latitudes with a temperate climate and when choosing an early variety of tomatoes, the timing of sowing tomatoes ranges from March 1-5; for southern latitudes, with a predominantly warm spring and, if you want to grow late-ripening varieties, the planting dates for tomatoes for greenhouses are postponed to the end of February. In any case, only seeds that have been processed and disinfected are sown.
When to plant tomato seedlings in a greenhouse
The gardener’s understandable desire to plant tomato seedlings early and harvest the first harvest, when the ovaries are just beginning to form in neighboring greenhouses, can result in the death of all seedlings or, in the best case scenario, an extension of the seedlings’ adaptation period. Excessive care for plants and transferring seedlings to a greenhouse when green “buds” have already formed on the lower fruit stems is also not the best option, since the first ovaries will most likely fall off during adaptation.So when is the best time to plant tomatoes in a greenhouse?
And again everything is decided by mathematical calculation, only now you have to evaluate the appearance of the seedling itself:
- 15 cm is the correct height for a short mature bush and 30 cm for a tall one;
- From 8 to 12 true leaves - this is how much a tomato bush should have, ready to be transplanted to a permanent place;
- from 5 to 7 mm - this should be the thickness of the stem;
- from 1 to 2 flowers without a hint of ovary formation is a good indicator that seedlings can be planted in a greenhouse.
Of course, even if all the above signs are present, the decisive factor in the matter of transplantation will be weather conditions. If we take the average spring without abnormal temperature indicators as a model, then the time frame for planting tomatoes can fall within the following framework:
- from April 27 to 29 – in a permanently heated permanent greenhouse;
- from May 2 to May 5 - in a permanent greenhouse without artificial heating, but with an internal film cover;
- from May 15 to 21 - in a permanent greenhouse without heating and a film tent inside;
- from May 23 to 28 - under a simple film frame mounted on arches.
In addition, we must remember that not all gardeners have the opportunity to grow seedlings on their own and go to the nearest market to buy them. How to determine the disembarkation time in this case?
Purchased seedlings must be planted on the day of purchase - it is impossible to rehabilitate them if the sprouts turn out to be non-viable. Therefore, immediately pay attention to the appearance of the seedlings and keep in mind that the sellers’ stories that the seedlings will magically come to life in the greenhouse are pure marketing ploys. Purchased plants should not:
- be limp or show signs of breakage on stems and leaves;
- have damaged, spotted leaves;
- have a thick stem and dense, leathery leaves;
- already be strewn with flowers or have ovaries.
You should definitely ask the seller whether the seedlings have been hardened and under what conditions. It is ideal if the plants turn out to be greenhouse-grown, that is, they have undergone adaptation in the same conditions where they will be grown in the future.
When to plant seedlings - the secrets of proper adaptation
We have already figured out that planting dates should be determined by the appearance of the plants and the temperature conditions in the greenhouse. Now let's talk about how to bring the tomato seedlings themselves to a state where transplanting to a new place will cause minimal harm to them. The most important stage of preparation will be hardening the tomatoes planted in individual containers, by bringing the conditions of their stay closer to those that await them in their permanent place.
When to plant tomatoes in a greenhouse? Two weeks before the expected date of planting the tomato in the greenhouse, the temperature in the room where the seedlings are located is artificially lowered, for which you simply need to open the upper sections of the windows. After 3-4 days of such “primary” adaptation, tomato seedlings can already be taken out to the balcony or placed in front of the open lower section of the window (if there is no draft). Gradually, over the course of a week, the presence of seedlings on the balcony is increased from one hour to six. Plants already in the greenhouse are hardened off by simply opening the frames for the same period.
At the end of the first week of adaptation, if the seedlings already have flowers, the entire plant is sprayed from a spray bottle with a solution of 0.5 g of boric acid and 0.5 liters of water. A couple of days before planting tomatoes in a greenhouse, pinch off the two lower leaves.However, this is not necessary if you are not sure of the accuracy of the timing of transplantation, since after pinching the leaves, the fruit cluster will begin to develop faster and it will be impossible to stop the process. In this case, the period when to plant tomatoes in the greenhouse will be dictated by necessity.
If the gardener decides to plant tomatoes early, or the tomatoes for seedlings have already gone through all the stages of preparation and it is undesirable to delay further, you should separate the plants that are already fully ripe from those that can still wait for replanting. A film tunnel is pulled inside an unheated greenhouse, preferably a double one, with a gap between the walls of 1 to 3 cm, and the fully prepared, hardened seedlings are transferred to a permanent place. Tomatoes for a greenhouse can thus be planted in several stages, which means the harvest can be extended over a longer period.
