PREPARATION OF SEEDS FOR SOWING
Preparation of seeds for sowing consists primarily of covering their surface with special chemical preparations, that is, on a chemical dressing. Small quantities of seeds sold in bags are sometimes treated in seed-for-sale companies and then this treatment is not needed.
Dry dressing consists in mixing seeds with an appropriate amount of the preparation. It is most convenient to do it in a foil bag, which should be destroyed after use, to avoid poisoning. Dressing is done for several days or just before sowing. Wet dressing, that is, a formulation solution, can only be done before sowing, when the seeds take up water, which stimulates them to sprout.
Soaking is used to accelerate seed germination, which only gives good results when sowing into moist soil and watering in drought conditions. This treatment is recommended for the cultivation of early cucumbers, when sowing slowly germinating seeds (e.g. carrots, parsley) and in the case of delayed sowing. The seeds placed in a flat dish are poured over with water, just to cover them. The water temperature should be between 20 do 30°C, depending on the plant's thermal requirements. The soaking time is usually 24 hours, the seeds of rapidly germinating plants are soaked for less time (1 2-20 hours), sprouting slower – longer (25-40 hours), germinating very slowly – by 30-50 hours. The water must be changed 2 times a day. If the seeds start to germinate, Stop soaking and sow lightly dried seeds immediately.
In some plants, the seed covers are often so impermeable to water, that the process of swelling and germination of seeds is significantly delayed or completely inhibited. To allow such seeds to germinate (e.g. palm trees, draceny, beadlets and many kinds of the legume family), mechanical is used, physical or chemical damage to the hard and impermeable seed coat. This action is called scarification. Mechanical damage to the seed coat consists in cutting it or rubbing it with a file or sandpaper. More often we resort to soaking the seeds in hot water (75-80°C) within 24 hours, or the seeds are treated with concentrated sulfuric acid for several or several hours. If we use sulfuric acid, we must rinse the seeds with water after the treatment, and sometimes even the residual acid neutralize with a solution of calcium hydroxide.
Seeds of many perennials, trees and shrubs in temperate zones, like pink, lilacs, peony, lily of the valley and clematis, sown even under the most favorable conditions, they only sprout after a few, and sometimes a dozen or so months. Such seeds are stratified, i.e.. surgery, which creates the best conditions for the secondary (aftermarket) seed ripening. Therefore, they are not sown immediately after harvesting, but is kept for a period of several, and even several months in containers filled with sand or peat at 0-8 ° C (optimum 4-5°C).