Watermelons are a favorite fruit of the summertime, and they are even more of a treat during the winter months. With watermelons grown in a greenhouse, it is possible to enjoy this summertime treat all year long.
Plant seeds into 3-inch pots that are filled with potting soil. Let the watermelon plants grow in these plants until they have developed two real leaves.
Place the watermelon plants in grow bags once the leaves have developed and place the plants into a greenhouse.
Create a support structure with dowel stakes for the vines of the watermelons to climb.
Tie the strongest shoot of the watermelon plant to the support and pinch off any side shoots. When the main shoot has reached the top of the support, pinch off the top of the vine to encourage the plant to focus on developing fruit instead of vines.
Water the soil consistently to keep it moist. Do not allow water to pool around the bottom of the plant. Water the plant by pouring water at the base of the plant and not on top of the plant leaves.
Pollinate the flowers with a soft paint brush by brushing each flower gently around midday when it is most humid.
Remove the male flowers four days after pollinating the flowers with the paint brush. The male flowers can be differentiated from the female flowers because the female flowers will show the bulge of a small melon growing behind the flower. The male flowers will not have a melon present behind the bloom.
Maintain the humidity of the greenhouse by watering the path of greenhouse in the early morning and leaving a standing bucket of water near the watermelon plants during the day.
Remove some of the leaves near the fruit when the watermelons are near full size. This will encourage the watermelon to ripen. Once the melons are ripe, remove them from the plant.