Seed germination and stand establishment of vegetable crops in different substrates under tropical conditions

In recent years, important changes have been observed in vegetable production in Brazil, including the way of stand establishment for such crops. Transplant production in plug trays is the major method employed in Brazil. Physical, chemical and biological properties of the substrates may influence seed germination and seedling development. Seed germination and stand establishment of beet, cabbage, lettuce, melon, onion, pepper, tomato and watermelon were evaluated in sixteen different commercial substrates. Electric conductivity (EC) and pH of each substrate were determined. Seed germination in laboratory conditions using pure water and water at different EC levels was also evaluated. The EC of substrates varied from 0.05 to 2.60 dS/m and the pH (in water) varied from 4.75 to 7.45. Seed germination and stand establishment were affected by substrates, under greenhouse conditions. In laboratory conditions, beet, pepper and tomato were more sensitive to higher salinity levels. Substrate type must be selected according not only to the crop, nutrition or irrigation system, but also to its properties, which may affect seed germination and stand establishment.