Tomato "Rio Grande"

* How to correctly calculate the timing of sowing seeds to obtain high-quality seedlings?
As you know, those crops that, in the conditions of a given area, do not have enough warm days for full ripening or in order to obtain an earlier harvest are grown through seedlings. For example, many types of cabbages and some other vegetable crops have a growing season of 150 days or more. In tomatoes, fruit ripening, depending on the variety and location, occurs on the 90-160th day after emergence. If tomatoes and sweet peppers are protected from the cold (in a greenhouse), then they can grow for more than a year.
To calculate the timing of sowing seeds in order to obtain high-quality seedlings, one should take into account the place of cultivation (open or closed ground, type of greenhouse), the growing season of the crop, the period from sowing the seeds to obtaining seedlings, and the quality of the seeds (germination energy). For example, tomato seeds retain normal germination for up to 7 years, and at a storage temperature of +14+16°C and a humidity of no more than 75% - 10 years or more. At temperatures within +22+25°C, tomato shoots appear 4-5 days after sowing. The optimal age of seedlings of this crop for planting in a permanent place is 45-65 days, depending on growing conditions.
For sweet pepper and eggplant, this period is 55-60 days, for cucumber, zucchini, and squash - 20-25 days. But root celery seedlings in Estonia remain in the seedling state for 60-90 days, and its seeds germinate 12-15 days after sowing. In this case, it is necessary to take into account, based on your conditions, the period for warming up the soil (open or closed ground) to a temperature of at least +12+14°C for heat-loving crops.
Therefore, if you plan to get an early harvest in a heated greenhouse, then sowing the seeds of tomato, sweet pepper, and eggplant can be done from the beginning of February. In this case, the seedlings must be provided with a sufficient amount of light energy (fluorescent lamps 12-14 hours a day).
When grown in a film greenhouse, sowing the seeds of these crops can begin in late February - early March.
​To grow tomatoes in open ground, if it is possible to protect the plants in May from possible frosts, the planting date for 45-60-day-old seedlings is May 15-20 or after the threat of frost has passed.