The average plant height Oporto varieties of onion (56.3 cm) was the highest at early spring sowing (20.03), and the average bulb weight (71.4 grams) – was the highest before winter sowing. The average height of plant varieties of Skvyrska (57.2 cm) was the highest for sowing 05.04, and average bulb weight (66.4 g) in early spring.

Biometric varieties of different ripening time of onions indicate before winter sowing time preference, which contributes to the formation of a larger number of leaves, their length, and aboveground parts of bulbous plants. This pattern is particularly evident for Early variety and Middle class and middle-to-best characteristics of growth and development manifested in early spring sowing.

The highest yields of early varieties of Chernyakivska variety (44kg/10m2) marked before winter sowing, which is 23 kg more than in late spring (20.04). The same pattern exists in middle-class bow Oporto. The highest yield of middle-class Skvyrska (36 kg/10m2) was observed under early spring sowing, which is 2 kg more than under winter and 9 kg more than in late spring sowing.

Harvested onions should be maintained properly to be used for consumption. Generally, losses from diseases in vegetable crops is inevitable, but they should be minimized. Tolerant varieties and hybrids of onion to pathogens have been bred., Fungicides inhibiting the activity of parasitic pathogens through preventive spraying are applying and during the growing season plants mass destruction. But bulbs may be affected by diseases such as bacterial rot, gray cervical rot, Fusarium and black mold while stored. In addition, significant weight loss in sprouted bulbs and vegetables is observed.

Studying the influence of sowing time on the quality of Chernyakivska early ripening variety shows that the maximum weight loss in bulbs (17%) seen are observed under late spring sowing (20.04). Also, losses in sprouted bulbs during storage, were higher (9.6%) under late spring sowing.

Thus, before winter way of sowing onion stands out due to its use promotes resistance against pathogens of bulbs, especially against cervical gray rot. Number of bulbs affected with bacterial rot and black mold in mid- spring (5.04) and late spring (20.01) seeding method was approximately the same. Defeat bulbs Fusarium did not depend significantly on the sowing time.

In general, the before winter sowing preserved almost all bulbs (95%) , and in late spring it made only 70%, or the loss amounted to 30%, from which we can conclude much better keeping quality bulbs under before winter sowing .

Top biometric indicators of Early and middle-class onion (linear growth of plants, the average weight of bulbs) are marked with before winter sowing (01.11), and the middle-in-early spring (20.03).

The highest yields of early ripening varieties of Chernyakivska onion varieties (44 kg/10m2 ) and Oparto middle-class (40 kg/10m2) marked with before winter sowing, which made respectively, 23 and 17 kg more than in late spring sowing. Middle Class Skvyrska onions ensure maximum yield in early spring sowing (20.03).

Onion optimum sowing time as process technology of its cultivation, increases the yield of early ripening varieties by 30-50% and Medium by 10-30%.

The largest losses in storage and diseases affect of onion were observed in late spring sowing (20.04), and resistant to the factors were the onions sown before winter.

Further scientific research is focused on the research of different ripening varieties of onions and turnip productivity depending on the layout of the area and supply.

Biometric indexes of different ripening varieties of onions indicate preference of before winter sowing time, which contributes to the formation of a larger number of leaves, their length, and aboveground parts of bulbous plants. This pattern is particularly evident for Early and Middle-class onion and middle- to - best characteristics of growth and development manifested in early spring sowing.

Key words: onion, varieties of different string maturation, growth and development of plants, biometrics, performance, storability.