Select an area outside that receives full sun. Like most herbs, basil is not fussy about its environment. However, it loves moisture and sunshine. Add organic compost to the soil to retain moisture.
Sow seeds directly in the ground after the danger of frost has passed in your region, and the soil has warmed to about 60 degrees Fahrenheit. If planted in cool soil, basil is prone to fungus attack. Dig a hole 1/2-inch deep and put two or three seeds in the hole. Space the holes six to 10 inches apart. Seeds should sprout in about 10 to 14 days. To have a nonstop supply of basil throughout the year, plant seeds at four-week intervals during the summer months. You'll be able to pick basil leaves until the first frost of winter.
Transplant seedlings from the local garden center in spring after the soil has warmed if you did not start plants from seeds. Dig each hole deep and wide enough for the root base to fit comfortably. Space the plants 10 inches apart.
Water the seeds or seedlings regularly. After the seeds germinate, thin the seedlings to one every 10 inches. Pinch the tips when the plants reach 6 inches tall to force bushier growth. Fertilizer sparingly, if at all.
Remove the flowers when the plant blossoms to encourage the plant to put its energies into developing leaves rather than flowers. Harvest basil leaves whenever you need them. The more you pick the leaves, the more and faster the plant grows.