How Long Does It Take for Flowers to Form on Watermelon Plants?
Watermelons (Citrullus spp. And cultivars) belong to the cucurbit family of vegetables that contains vining garden plants such as cucumbers, pumpkins and squash. They demand a long warm season to flower and fruit, ideally 80 to 90 days with temperatures over 80 degrees Fahrenheit. Most will flower four to eight weeks in the time of seed germination, depending on the number planted, land culture and growing states.
Watermelon seeds require a minimum soil temperature of 60 degrees Fahrenheit to germinate. Seeds may be started inside two to three weeks before planting. Watermelon plants prefer sandy loam soils rich in organic matter, complete sun and growing temperatures between 80 and 90 degrees Fahrenheit. Clay soils can be amended with organic matter and mulched in raised rows. The Utah State University Cooperative Extension proposes using black plastic mulches together with row covers for earlier planting and adulthood but caution not to apply organic mulches to watermelon rows till after the soil temperature has reached 75 degrees Fahrenheit. Heavy rain or overwatering and temperature extremes could reduce sweetness of melons.
Early blooming hybrids will flower first. These require the shortest growing season, usually 70 to 75 days to fruit crop. These sometimes feature smaller fruits than traditional varieties. Blooms will likely appear in four to six weeks when growing conditions are best. Recommended varieties include “Golden Crown,” “Sugar Baby,” “Yellow Baby,” “Yellow Doll,” “Petite Sweet” and “Super Sweet.”
Main Season Varieties
Conventional hybrids and species, also known as main season types, will flower a little afterwards. These require a slightly longer growing season, usually 80 to 85 days to fruit crop. Blooms may seem anytime in a four- to eight-week period. Recommended varieties include “Charleston Gray,” “Crimson Sweet,” “Medera,” “Parker,” “Sangria,” “Sunny’s Pride,” “Sweet Favorite” and “Mirage.”
Seedless watermelon varieties (all are triploid hybrids), also require 80 to 85 times before fruit crop in the time of planting. These will blossom in the exact same four- to eight-week window as principal season types. Recommended varieties include “Cotton Candy,” “Crimson Trio,” “Honey ‘Heart,” “Jack of Hearts,” “Queen of Hearts,” “Nova” and “Tiffany.”
Watermelon plants are a favorite food of cucumber beetles. Row covers left in position until plants flower can mitigate their damage. Remove row covers after bloom to encourage pollination by bees. Blossom-end decay can happen in extremely dry conditions or when roots are affected too intensely or often by hoeing. Watermelons are also vulnerable to a number of diseases. Rotate planted varieties from year to year and plant quality seeds in varieties with recognized disease resistance.