If you want a head start on growing watermelons seeds then try soaking them in milk. By doing this, you will help them to sprout more quickly. Living in the northern United States, it is a problem in getting out gardens to growing in the short season of time. Watermelons require a long hot growing season and if you live in the northern United States, the watermelon plants need a head start on growing. You can start them in a cold frame or greenhouse at least a month before the last frost. Six weeks later, you can plant them into your prepared garden area. Just by soaking your seeds for one day will help. It tricks them into thinking they were in the ground for at least a week. The milk penetrates the hull of the seed, providing nourishment for the life force that is inside the seeds. The seeds soak up the milk and change color. If the seed coats contain a virus that is harmful to the life of the plant, the milk will help to inactivate that virus.
Warm the Milk
Find a bowl and place your watermelon seeds inside. If you are not planting many seeds, you can use a shallow bowl or saucer. Warm up enough milk to submerge the seeds completely. It is important that you do not heat the milk to the boiling point. That is way too hot. If you do that, you run the risk of throwing your watermelon seeds into shock. Ultimately. this will kill your seeds. The right temperature you need is more like the milk you put into a baby bottle.
When the milk is warm, pour this over the seeds in your bowl. Make sure you have enough to cover them. You need at least 3 inches of milk in your bowl. Leave the mixture setting in the bowl for 24 hours.
After that amount of time, check them to see if the seeds have changed. If they are swollen and lighter in color, then they have absorbed enough milk to plant. Now all you need to do is plant them into your garden.
Prepare Your Garden Space
With a tiller or garden fork, work up the area where you want to plant your watermelon seeds. Incorporate leaves, grass and rich compost and dome well-rotted manure into the garden bed. Watermelons like to have a well draining soil, so it would not be amiss to add some sand to the soil as well.
Plant the soaked seeds one inch deep in hills. Plant at least six seeds per hill and space each hill 6 feet apart. Make your rows between seven and 10 feet apart. When the watermelon plants become established, thin them down to the best three plants per hill. This is the hardest part for me. To pull plants out of the ground when they are growing, but in order for the watermelon plants to thrive and produce watermelon, they need the extra growing room.
Mulch the Plants
Heavily mulch the plants to keep the moisture content in the soil after the spring sun has warmed the soil. Watermelons prefer a slightly acidic soil of a 6.0 to 7.0. For the most flavorful watermelon, leave them to ripen on the vine. It should have a white skin underneath where it rested against the soil. It will look slightly pebbly and leathery in appearance. The tendrils near the fruit turn dry and dark when fruit is ripe. One way to tell if a watermelon is ripe is to thump it. If it sounds hollow, it should mean it is ripe enough to pick.