The aim of this study is to evaluate onion sprouting behavior after using natural compounds and heat treatment for extending onion storage life. “White” cultivar was used and the effect of burning basal plate (15, 30, 45 and 60s 100 ºC), submerging in essential oils (EO) suspension of Black zira (Bunium persicum) and Clove (Eugenia caryophyllata) at 500 and 1000 ppm or fumigation with Bunium persicum essential oils (0, 25, 50, 100 and 150 ppm) was studied. The experiments were conducted in glass jar (3 L) during 50 days in room temperature (25±1 ºC). Bulb weight, sprout length, fresh and dry weight of sprout, weight loss percentage, infected bulb and onion quality of the treated bulb were determined initially and after storage time. Results indicated that the lowest weight loss (3%w/w) occurred in fumigation method and the highest one (60%w/w) was observed in 45s burning. The growth of sprout was the highest (21cm) in submerging method in 500ppm Clove EO whereas 60s burning bulbs produced the lowest (1cm) sprout length. Fresh and dry weight of sprout/bulb was higher in 30s burning than 45s. The best quality of onion obtained in the treatment of 500 ppm Black zira EO by the method of submerging (21.67%) in contrary to fumigation treatments (85.23%).

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