In northern and challenging climates, start your watermelon seed indoors about 4 weeks before the soil in your garden usually warms up. Then transplant on a cloudy day to hills including three plants, spaced a foot or so apart. Be sure these transplants are watered well in the weeks after planting and shelter against bad winds with row covers or even a wall of wooden shingles protecting against the prevailing wind. (Do not, however, shade the plants as they need sunshine.)
In other climates, you may easily direct seed your watermelon seeds into rows, with plants a foot or so apart or in hills which are about 2′ across and three or so inches high. Plant five seeds, well apart, an inch deep. Water well. When the plants emerge, thin to the three sturdiest seedlings. Harvest when there is a yellow spot on the under side of the melon and the tendril nearest the melon has dried up.
Watermelon is perhaps the easiest crop from which to save seed. As you happily eat on a juicy, ripe melon, just spit the seeds out into a bowl. Rinse the seeds then drain and lay out on a plastic plate to dry in a protected spot. When thoroughly dry, store in an airtight container which is rodent/insect-proof. Watermelons are insect pollinated so different varieties grown within your garden will cross. So only choose to grow one variety per year. They will not cross with muskmelons, squash or cucumbers.
WATERMELON About 25 seeds per pack
Blacktail Mountain A great favorite of we gardeners who grow in inhospitable climates! Bred by Glenn Drowns, this round 5-10 pound very dark watermelon with faint stripes has excellent pink, juicy, sweet, crisp flesh. Juice just runs down our chins when we gobble the first ripe melon of the year. We direct seed into a hoop house and harvest ripe melons around September 6th on till freezing. 75 days
Bozeman watermelons were a surprise to us. Developed by a breeder in Montana, these nice, large, roundish, light green skinned melons were not only hugely productive but really sweet. And early too! They came in strong just five days after our Blacktail Mountains, at 80 days. We gobbled them up! Ours weighed 10-14 pounds, grown in our Sand Garden, which was a new garden spot for us. We were impressed! 80 days
Sweet Dakota Rose
Sweet Dakota Rose This deliciously sweet, medium-sized watermelon with bright red flesh and few seeds was developed by North Dakota farmer David Podoll to grow in cool, short season climates. Every year our high altitude and northern customers sing its praises as the juice drips down their chins. 85 days