In order to study the impact of sowing date, planting pattern and nitrogen on the indices of buckwheat seed growth and yield, in summer plantation, a factorial plot split design with completely randomized blocks and three replicates has been conducted in Agricultural Research Center, Arak in 2018-2019. Planting pattern treatments as the primary factors included two levels of 50cm mound with two 20cm sowing rows (P₁) and 60cm mound with three 15cm sowing rows (P₂). Sowing date treatments included four levels of 20th June (D₁), 5th July (D₂), 20th July (D₃) and 5th August (D₄) and nitrogen treatments included four levels of 0 (N₁), 50 (N₂), 100 (N₃) and 150 (N₄) kgh^–1 considered as secondary factors. Research results indicated that triple interactions of sowing date, planting pattern and nitrogen were significant on seed yield, leaf area, growth speed and net absorption speed of plants. The most seed yield and LAI (leaf area index) were 1967kgha^–1 and 3.06 related to the treatment P₂D₁N₃. The most CGR were 2.86, 17.48, 19.04, 24.64 and 14.64gm² related to P₂D₁N₃, cultivation, respectively. The most NAR was 4.93gm² related to and P₂D₁N₂ for 15, 30, 45, 60 and 75 days after the cultivation. Therefore, buckwheat with nutritional characteristics, adaptation and good yield as a new plant can enter the cultivation patterns in different regions of the world.

buckwheat, planting pattern, sowing date, nitrogen, summer cultivation.