The timing of sowing tomatoes for seedlings directly affects the health and condition of the plants by the time they are planted in a permanent location.
The stronger, more leafy and developed your seedlings are, the faster they will take root in a new place, overcome planting stress, and enter the phase of active fruiting.
According to reviews from experienced summer residents who independently grow vegetable and flower seedlings at home or in closed heated structures on their personal plots, sowing dates vary not only depending on the expected dates for planting bushes in the beds, but also on the method of growing seedling crops.
This method allows you to grow the maximum number of bushes with a minimum window sill area.
First, tomatoes are sown at a distance of 1 cm in a common bowl, and then in the cotyledon leaf phase they are transplanted into boxes in rows (distance 2-3 cm in a row and distance 5 cm between rows). With this method, the plants are planted in a permanent place 25-30 days after the emergence of mass shoots.
There is no point in keeping plants that actively compete for both light and nutrition in a common box for a longer period of time as they grow.
Otherwise, the quality of seedlings will deteriorate. Therefore, sowing is carried out in March for early harvest bushes in warm greenhouses, in April for plants in cold greenhouses and hotbeds, and in early May for open ground seedlings.
Tomatoes, the seedlings of which are grown in cassettes, are planted in beds at the age of 30-35 days. This is due to the limited volume of soil in each cell and the impossibility of moving the plants apart as they grow and develop.
If you keep the plants in the cassettes for too long, you cannot avoid the bushes stretching out. In a small volume of soil lump, the roots completely master the substrate in 3 weeks, after which the active growth of the above-ground part begins, which lacks light, air, and nutrition.
If you plan to grow tomato seedlings in cassette cells, then for planting plants in heated greenhouses, sowing is carried out in March, in unheated ones - in March - April, and in open ground - until the end of April. There is no point in earlier sowing. It is better to wait a little than to try in every possible way to slow down the development of plants and prevent their stretching and thinning of stems.
Tomatoes that will immediately grow in individual planting containers are planted in beds at the age of 55-60 days from the moment of mass shoots emergence. With this growing technology, each bush grows in a soil lump volume of at least 0.5 l.
Moreover, the older the seedlings become, the more light and air they require. Therefore, when placing the cups on a windowsill or in a greenhouse, you need to leave space for them to move apart.
The exact timing of sowing tomatoes for seedlings is determined in each specific case, based on the planned timing of planting the plants in a permanent place. So seedling bushes that will live in heated greenhouses are sown in February so that the seedlings are formed by April. And plants that will be planted in open ground in late May - early June are sown in early April.