Efficiency of the sowing date of spinach in the southern steppe conditions of Ukraine

The population of Ukraine should receive fresh greens from early spring to autumn from open field production and the period of growing spinach will ensure the supply of fresh greens. The purpose of the research was to study the possibility of extending the period of fresh greens supplying from the open field due to the extension of the seed sowing period in the open field. The research was conducted in 2019-2021 in the conditions of the Southern Steppe of Ukraine. For the research, field, statistical, calculationanalytical and laboratory methods were used. The varieties Fantaziia and Malakhit were studied. The behaviour of plants after six sowing dates was examined. The control variant was the variety Fantaziia for sowing in the 1st decade of April. It was found that plants of both varieties of spinach had a larger leaf surface (114.2-127.7 cm2 ) in the early sowing period. Plants which were sown in August had a smaller leaf surface – 86.0-106.2 cm2 . The highest yield of marketable green mass was obtained for sowing in the 3rd decade of April and 2nd decade of May. The variety Fantasia provided 22.9-23.0 t/ha, and the variety Malakhit provided 23.3-23.9 t/ha. The sowing date had a significant influence on the main chemical parameters of spinach of the Fantaziia and Malakhit varieties. The higher indicators were the sowing dates in the third decade of April and the second decade of May, when the brix reached the level of 6.4-6.8%, the sugars content – 2.3-2.4% and the content of vitamin C – 58-70 mg/100 g. It was established that the soil and climatic conditions of the Southern Steppe of Ukraine were suitable for sowing spinach in six dates and would ensure an uninterrupted supply of products from the 3rd decade of April to the end of September inclusive, and in years with favourable weather conditions in the 2nd to 3rd decades September to mid-October. Such approach will solve the problem of seasonality in the consumption of fresh vegetables. The sowing dates are recommended to agricultural producers of spinach in order to extend the period of receiving fresh greens from the 3rd decade of April to the end of September and in some years to the middle of October