Abstract
Producing leek seeds without replanting one-year-old plants is cheaper and more practical, but can be risky in climates with cold winters. This research aimed to assess whether accelerating the planting of seedlings and using Fulvohumin fertilizer, containing, among others, humic acids can make such production less risky. Three dates were used for planting leek seedlings: April 10, April 25, and May 10. Fulvohumin was used presowing, foliarly, and both. Both factors significantly improved seed production. The best results were obtained at the earliest planting date, as the plants were strong and best prepared for the generative phase and the frost period. Fulvohumin significantly improved growth and development parameters, mainly when used before sowing and as foliar application. In the best combination, with two applications of fertilizers, the seed yield increased by 39%, compared to the control (without Fulvohumin fertilization), and the seed yield of plants planted on April 10 was 17% higher compared to plants planted on April 25 (considered as standard) and 39% higher than those planted on May 10. Seed yield varied in the three subsequent years of the study, but each year, the planting date and Fulvohumin had a similar effect on seed yield.