Egusi watermelon, also called "wild watermelon," is grown throughout Nigeria and the Congo for its seeds, which are high in protein and carbohydrates. In Nigeria, it often grows wild, but it is also farmed as an increasingly important cash crop. The white, bitter flesh of the egusi is not edible, but the seeds are a staple of local diet. Egusi is easy to grow in Nigeria's warm, arid climate.
Plan to plant egusi seeds in Nigeria in August, after harvest of other fruits and vegetables is nearly complete. Obtain a supply of seed at a local market.
Choose a site for planting egusi that will be sheltered, such as the margin of a garden, in between other plantings or near the edge of woods. Egusi do not do well in open, flat fields.
Till the earth of your watermelon patch with a shovel or spade to a depth of 8 inches, breaking up clods and clumps of dirt until you have a fine, loose mix. Add manure and other organic compost as you go to boost the nutrients in the soil.
Plant three to four egusi seeds per hole at a depth of 2 inches, with each planting 18 inches apart. Cover with dirt and water thoroughly. Watch for seedlings to appear in six to eight days.
Add more manure or organic compost to the soil when seedlings are fully established, and they will flourish. Provide support for egusi vines by staking and tying, or setting up trellises. Continue watering on a regular basis throughout the growing season.
Harvest egusi watermelons when the stems dry and the fruit turns from green to white or yellowish-white.
Break open egusi melons after harvest and leave for a week or two to decompose before collecting the seeds. Decaying melons smell bad, so do this a good distance from your home.