Planting Watermelon

In cooler climate regions, seeds should be started indoors 2-3 weeks before the final frost date for best results in the garden. Watermelons require a lot of nutrients, so a week before planting in the garden, work compost or manure into the soil. Plant seeds 1cm (1/2") deep, 90cm (36") apart, with the same distance between rows. Watermelons prefer loamy, well-draining soil rich in organic matter, and require full sun.

Growing Watermelon

As they grow, watermelons will vine out and spread. For smaller gardens, training the vines up a fence or trellis will help to save space, which has the added benefit of protecting fruit from damage on the ground. However, additional support will be required as the fruit matures to prevent damage to the plant. Watermelons require consistent watering, and will greatly benefit from mulch to discourage evaporation. When watering, avoid getting the leaves wet, as this can encourage diseases which would damage the plant.

If you choose to fertilise, use a nitrogen-rich fertiliser early in the plant's life to encourage leaf production, but a low-nitrogen fertiliser once flowering begins to instead encourage flowers and fruit. As fruit develops, gently lift it and place cardboard between it and the soil to prevent rotting.

Harvesting Watermelon

There are several ways to tell if a watermelon is ripe. The main method is to tap on the fruit, and if it sounds hollow, it's ready for harvest. There are also visual clues: the colour on the bottom of the watermelon (from where it was growing) will be cream or yellow rather than white, the tendril will be wilting or dead, and the stripes will be close in colour.

Harvest by cutting the stem close to the fruit and store in a cool dry place. Once the fruit has been cut, watermelon should be tightly wrapped in plastic and stored in the refrigerator.