70 days. Not all varieties that do well here in the Northeast came from the Northeast. Seed growing guru Glenn Drowns (of the Sand Hill Preservation Center) developed this modern heirloom in Idaho in the cool summers of the 1970s. These deep green fruits have the same color and texture you'd expect from a southern watermelon but are smaller and more round weighing in at 6-10 pounds. If you only grew one watermelon in your garden, spit out the seeds as you eat and save them to plant next year.