To grow arugula, plant the seeds in rich, evenly moist soil as soon as the ground thaws in the spring. Amend the soil to achieve a pH of 6 to 6.8 if necessary. Space the seeds 1-inch apart, and cover the seeds with a 1/4-inch layer of soil. Gradually thin the plants until they are at least 6 inches apart. In summer, plant arugula in partial shade.
To prevent bolting, water the soil regularly and harvest the plant when the center stalk begins to grow. When growing arugula in the garden, work compost into the soil before planting. After planting the seeds, apply a time-released fertilizer according to the instructions on the product packaging.
After four weeks, pick the outer leaves on the plant and allow the center to remain undisturbed. Arugula continues to produce new outer leaves for several weeks.
To produce strongly flavored arugula, wait until flowers appear to pick the leaves. The flowers are also edible but very strongly flavored. After the plant flowers, pull it up. If desired, plant new seeds or seedlings, but choose a location that is shady if the weather is hot. Stagger plantings two to three weeks apart to maintain a steady supply of arugula throughout the growing season.