Choose a planting area in full sun, preferably a spot along an existing fence or other support, to provide your luffa vines with something to climb.
Prepare the planting area in spring. Cultivate the soil to a depth of 12 inches. Work several inches of composted manure and other compost into the top 6 inches.
Plant luffa seeds in spring after all danger of frost is past and when the soil is thoroughly warm, at least 65 to 70 degrees Fahrenheit to a depth of 4 to 6 inches. You can also start luffa seeds in peat pots several weeks earlier, to get a head start on the growing season. Nick luffa seeds with a knife and soak them in warm water for 48 hours for better germination.
Sow seeds 1/2 inch deep and at least 12 inches apart along a fence or other sturdy support. If you prefer to grow them in a hill without support, plant three or four seeds in each hill, and space hills 4 to 6 feet apart. Water the planting area thoroughly. Luffas may take two weeks to sprout.
Mulch the area above and near roots with several inches of pine straw, shredded leaves, dried grass clippings or other organic mulch when seedlings are 3 to 4 inches tall.
Remove each vine's first four lateral branches to support stronger fruit.