Muskmelon Seeds F-1 Hybrid US-111Overview Muskmelon plants flourish well under warm climate and cannot tolerate frost. The optimum temperature for germination of the seed is 27 30C. Dry weather with clear sunshine during ripening ensures a high sugar content, better flavor and a high percentage of marketable fruits. High humidity increases the incidence of diseases, particularly those affecting foliage. Cool nights and warm days are ideal for accumulation of sugars in the fruits