Tomato seeding and seedling cultivation
Tomato is very valuable vegetable. It contain soluble sugars, organic acids, cellulose, pectin, protein, fat, minerals (potassium, phosphorus, sulfur, magnesium, calcium, iron, copper, sodium) is rich in vitamins (B1, B2, B3, PP, C, A, I, H) and has alkaloid tomatine possessing phytoncide properties. Also it contains especially valuable substance – lycopene, that gives the tomato the red color. Tomato prevents oxidation processes in the body, neutralizes hazardous substances, so called – free radicals, that often causes oncoligical and cardiovascular diseases. 
Variety of species. Tomato hybrids differ in plant height, fruit size and color as well as fruiting earliness. Inderteminating hybrids are tall, of unlimited growth. The first cluster forms above the 8th – 11th leaf with the new inflorescence every third leaf. The most popular species: ‘Isabel F1‘, ‘Rondelo F1‘, ‘Erophily F1‘, ‘Admiro F1‘, ‘Brooklyn F1‘. They are best suited for growing in heated greenhouses. Determinating hybrids are of limited growth; their stems usually end at formation of 4-6 or more inflorescence clusters. The first cluster forms above the 6th – 8th leaf with the new inflorescence every 1-2 leafs. The most popular species: ‘Magnus F1‘, ‘Platus F1‘, ‘Vulkanus F1‘,‘Celzus F1‘. They are best suited for growing in non-heated polyethylene and glass greenhouses in peat substrate. The foreign seed companies sell thermally and chemically processed tomato seeds, which package bears the disease resistance alphabetical initials.
Seeding. Duration of tomato growing is quite long, due to their seedlings are grown in heated greenhouses and it grows within 50-70 days after the seeding. It seeding time depends on seedlings reseeding time into the heated or spring, non-heated greenhouses. The seeds of the tomatoes are best to be sown into a clean, loose, high-quality, fine fraction (0-5 mm) substrate made of ecologically certified peat (pH 5,5-6,5; EC-1,2-1,8 mS/cm), containing needed (optimal) amount of macro and micro nutrients. Prior to the tomato seed seeding, the substrate needs to be aired and additionally wetted. Plastic boxes or special seedling boxes disinfected with 0,2 percent (10 l water add with 20 ml of product) previcur solution shall be filled with the special made substrate for sowing. Peat substrate surface must be smoothened and easily compressed with the plank. Then 1 cm deep grooves shall be made every 3 cm, where the seeds shall be set-out and latter backfilled with 3 mm peat layer. This peat substrate for sowing, grants the optimal conditions of seedlings germination and cultivation as well as the best quality of seedlings and future harvest. Garden soil cannot be used, as there is a high probability to bring in pathogens and harmful substances.
Seeds germinate at 24-28 oC temperature within 4-6 days. After the seedlings have sprouted, the covering foil shall be removed and boxes shall be placed into the brighter and cooler place for 3-4 days, maintaining the day temperature of 12-15 oC and night temperature of 8-10 oC, to allow for better formation of roots. The optimal air temperature to be maintained during the seedlings growing is 20-22 oC and during the night 15-17 oC, while of the substrate 16-18 oC.
After the seedlings have the first real leaf, they shall be pricked out into the pots of 10-12 cm wide, filled with the peat substrate for sowing. They shall be planted deeper than they have grown. Only healthy, strong seedlings with the good root are to be pricked out. Prior to the use of specially made substrate, it shall be aired and properly wetted. It is not recommended to mix compost or garden soil with the specially made peat substrate.
Seedling cultivation. Tomato seedlings are to be grown in heated greenhouses, best on the racks, equipped with the under heating. The pots with the plants shall be placed every 15 ea/m2 on the racks, so that they leafs would not touch, thus tomato seedlings shall be strong, compact and not elongated. Seedlings have to be wetted quite seldom, but abundantly with warm water. Peat substrate in the pot shall be moist, bet not wet.
Tomato seedlings must be additionally fertilized with 0,15 percent Nutricomplex (14-11-25) complex fertilizer solution, after 2-3 weeks. At the beginning, the roots of the seedlings form better at a lower salt concentration. Lack of separate elements shall be prevented during the seedlings growing. In case of any element lack, the normal growth is disrupted immediately. However, the excessive fertilization is rather harmful too. Then the seedlings have very well-formed aboveground part, leaving the root system poorly formed as well as the inflorescence clusters.
Well grown tomato seedlings shall be healthy, non-overgrown, non-elongated, with green leafs. Seedlings to be planted into the greenhouses must have 10-12 leafs, while to be planted outdoors – 7-8 leafs and well-formed root system. Prior to the planting to permanent growing place, tomato seedlings must be preventive watered with 0,15 percent concentration previcur solution against the root diseases.
