Also known as “rocket” or “roquette,” arugula is a fast-growing, cool-season leafy green that exhibits a tangy, mustard-like flavor. As a member of the mustard family (Brassicaceae), it’s related to other common garden plants, including cabbage, broccoli, and kale. Arugula is commonly found in mesclun seed mixes because it grows quickly and embodies a much bolder flavor compared to most greens. Be sure to plant in early spring or early fall so you’ll be able to harvest young leaves 6 to 8 weeks after sowing. The seeds will germinate quickly in cool soil and seedlings are able to tolerate a light frost; however, consider protecting plants with cloches or row covers.
Planting and Growing Information:
Arugula grows best in nutrient-rich, well-drained soil, although it will tolerate a wide variety of conditions, which makes it a great choice for containers, raised beds, or traditional flower garden beds. It prefers slightly acidic soil with a pH between 6 and 7. To receive the best results, plant in a spot that gets full sun (6 or more hours of sunlight). It will grow in partial sun, but not as well as full sun. To avoid pests and disease, avoid planting arugula where its relatives (other Brassicas) have recently been planted.
Arugula seeds will germinate in soil temperatures as low as 40°F, so make sure to sow them outdoors as soon as the soil can be worked in spring. For a fall or winter harvest, sow in late summer or early fall. Sow seeds ¼ inch deep apart in rows 10 inches apart. An alternative method would be to broadcast arugula seeds alone or mix with other salad greens. While seeds germinate in about a week (or slightly longer in cold soil), to speed up germination, soak seeds in water for a few hours prior to planting. For a continuous harvest later on, sow new seeds every 2 to 3 weeks.
Make sure to keep soil evenly moist, especially in warmer weather when bolting could occur. Bolting entails the plant skipping right to producing flowers and seeds without developing much foliage first. Thin seedlings to about 6 inches apart. To decrease heat stress and prevent bolting, provide some shade for warm-season plantings.
Given arugula grows so fast, a single application of a high-nitrogen fertilizer or rich compost mixed into the soil during planting time is usually enough. Additional feeding is only required if the leaves are light green and clearly undernourished, which can happen in very poor soil.
The arugula leaves taste better when they’re young whereas older leaves can be tougher and have a strong flavor. Be sure to harvest leaves when they’re about 2-3 inches long. Pull up the whole plants or cut individual leaves as needed. The white flowers are also edible.