Remove weeds, rocks and old roots from the soil bed with a garden fork. Loosen the soil to a depth of 10 inches. Add a 3 to 4 inch layer of organic compost to the soil. Run a rake over the soil to smooth out the compost.
Plant the arugula seeds on the soil's surface and cover with a 1/8 layer of coarse sand. Space seeds 1 inch apart in rows. Water the seeds thoroughly with a garden hose after planting and during germination. Fertilize the soil with cottonseed meal after planting to promote healthy grow.
Remove closely spaced plants by thinning them 1 to 2 inches with scissors. Cuttings can be composted, consumed or transplanted back into the soil about 12 inches apart.
Harvest arugula approximately 25 to 40 days after planting. Use scissors to cut the outer leaves, so the plant remains intact and produces new leaves. Place harvested cuttings in plastic bags for storage. Continue harvesting the fast-growing leaves every three to four weeks until the first fall frost.