Arugula (Eruca vesicaria subsp. sativa) is a fast-growing annual vegetable that you can start planting in early spring or late summer and can replant throughout each growing season. This not only ensures a bountiful harvest; it also encourages you to pick the leaves early, when they have a fresh, peppery zing but without the bitterness of mature leaves. Waiting until the plants mature and flower, or bolt, renders the leaves unpalatable, although both the flowers and the mature leaves are edible.
Arugula is one of the cold-season vegetables, along with spinach, kale, and others. It is ready to harvest about 40 days after seeding. If you time it right, you can have two arugula seasons, one in spring to early summer and another in late summer into fall. It won't grow well in the high heat of midsummer. Arugula plants are relatively small and self-contained, so they're easy to grow in containers or any garden space.
|Botanical Name||Eruca vesicaria subsp. sativa|
|Common Name||Arugula, rocket, roquette|
|Plant Type||Annual vegetable|
|Mature Size||12 inches tall and wide|
|Sun Exposure||Full sun|
|Soil Type||Humus-rich, well-drained|
|Soil pH||6.0 to 7.0|
|Bloom Time||Seasonal bloomer|
|Flower Color||Yellow, white|
|Hardiness Zones||Annual plant; grows in zones 3 to 11|
Most gardeners start arugula from seed. It can be direct-seeded into the garden about one to two weeks before the final frost in spring. Like most salad greens, arugula seeds are tiny, so you have to be careful not to plant them too deep. Choose a location (or locate your container) in full sun or, for a longer season, an area with midday shade. To sow the seeds:
- Prepare the soil with compost or a high-nitrogen fertilizer (or fill your container with potting mix), and gently flatten it out with your hand.
- Distribute the seeds as uniformly as possible over the soil.
- Gently pat the seeds onto the soil with your palm.
- Cover the seeds very lightly with soil or seed starting mix over the seeds, and pat gently.
- Add water carefully, either using a rose attachment or a gentle spray from the hose. You don't want the water pressure or weight of the water to disturb your seeds and drive them too deeply into the soil.
Once the seedlings emerge, thin them to a spacing of 4 to 6 inches (eat the baby greens right away; they're delicious!). If you love arugula, you can succession plant more seeds every two weeks to make the most of the growing season while the mild temperatures last.
Arugula grows best in full sun, but it doesn't like a lot of heat. If possible, grow it in full sun while the weather is relatively cool, then provide some afternoon shade as the temperature rises.
Arugula plants are happiest in well-drained soil that is slightly acidic to neutral, about 6.0 to 7.0 pH. It tolerates a variety of soil types but likes it fairly rich; add compost or high-nitrogen fertilizer as needed.
Like many vegetables, arugula needs regular watering for healthy, consistent growth and optimal flavor. Keep the soil consistently moist, watering as soon as the top 1 inch of soil feels dry. In dry climates, this may mean watering every morning. If you fail to water regularly, you'll force the plants to bolt, ruining the flavor of the leaves.
Temperature and Humidity
The ideal temperature range for arugula plants is between 45 and 65 degrees Fahrenheit. It can't survive a frost, and it doesn't like the high heat of summer. You can extend its growing season somewhat by protecting it from cold with row covers, and from heat with shading, but the best strategy is to plant it at the right times and harvest the leaves as soon as they're ready. It does not need high humidity and grows quite well in arid climates, provided it gets enough water.
As long as you plant your arugula in nitrogen-rich soil, it shouldn't need additional feeding. Pale leaves indicate a lack of nourishment.
Varieties of Arugula
- 'Astro II' might be considered a good "starter" variety, for those who prefer a mild arugula flavor profile. It's also matures relatively early, in as little as 7 weeks.
- 'Apollo' is another mild variety. It is relatively heat-tolerant and has oval leaves.
- 'Olive Leaf': Italian speakers know this better as Rucola Selvatica a Foglia D'Ulivo. This wild variety has flat, narrow leaves with spicy yet not overpowering flavor.
- 'Red Dragon' is ideal for salads, with its striking, purple-veined leaves that are shaped like oak leaves and have a mild flavor.
- 'Sylvetta' is prized for being particularly slow to bolt. Its leaves are narrow and spicy.
Growing in Containers
Because the roots of arugula are relatively shallow, you don't need a giant or deep container to grow the plant. However, consider planting a fair amount of arugula—once you get a taste for it, you might find you're eating a lot! Therefore, pick a container that's wide. Although you can grow arugula in almost anything, a self-watering container makes the whole task a lot easier.
Your arugula should be full grown and ready to harvest in about four to seven weeks, depending on the variety. The younger the leaves, the more tender and sweet they will be, so don't wait too long to start picking them.
Once the seedlings are 3 to 4 inches long, you can either pull out the whole plant or thin them out. If you want the plants to continue to grow, you can collect just the outer leaves by cutting or tearing them off toward the base, and leave the crown intact. Alternatively, you can cut off all the leaves just above the soil, and the plant may regrow if the weather is still relatively cool.
If you wait too long to harvest and the plant bolts, eat the flowers but not the leaves. The flowers appear after the leaves have grown to full size and are too bitter to eat. Pick the flowers off and eat them or add them to a salad or an open-faced sandwich for a beautiful treat. You can also grow some arugula plants for the flowers alone.
Common Pests and Diseases
The short, early growing season of arugula means that you'll miss most pest infestations in the spring, but perhaps not if you plant again in late summer. Arugula plants are favored by slugs as well as cabbage loopers, flea beetles, aphids, and diamondback moths. Keep an eye out for insect eggs, and remove any you find by hand. Aphids can be sprayed off with water. Stop slugs from reaching the tender leaves with beer traps, diatomaceous earth, or another traditional method.