Cultivation of Saffron

Saffron, an autumn crocus that produces a highly valuable spice, is grown mainly in Mediterranean climates. Nevertheless, saffron farms have been established recently in the province of Quebec. This led us to test cultivation practices that could influence plant phenology, saffron yield, and corm growth, including planting depth, planting period, and the application of fertilizers, mycorrhizal fungi, and biostimulants at planting. Soil temperature was monitored at the different planting depths throughout the year. Floral initiation was also monitored during spring and summer. Shoot emergence was delayed and final emergence reduced as planting depth increased; however, more shoots were produced by shallow-planted corms, which could lead to the production of corms too small to flower. The best time for planting saffron corm is between the end of July and the third week of August. Mineral fertilization hastened leaf emergence and improved corm production and their nutrient content. Neither the addition of mycorrhizal fungi or of biostimulants had any significant impact on saffron growth or flowering. Floral induction likely took place in July as flower bud appeared in early August. In most years, flower and saffron production was low in this location. It appears that soil temperature did not remain high for long enough during the summer to promote floral induction and autumn temperatures decreased too fast, limiting shoot and flower emergence most years. However, these climatic conditions did not affect corm production; corms could thus be sold to secure revenues for producers.