In the article results of researches with definition of density of crops, productivity of seeds and fiber of fibre flax grades Vruchiy are shown at use of various kinds and doses of mineral fertilizers. The highest yields of seeds and fiber for the averaged data of 2011-2013 were obtained with the introduction of mineral fertilizers in the form of fertilizer N51P51K51 for pre-sowing cultivation and the index was 0.78 and 1.47 t / ha. The highest indicator of the number of plants per m2 is the same coefficient of conservation of plants obtained on the same fertilizer version and was 1679 pcs. the 87.6%.