Arugula (Eruca vesicaria) is an annual cool-season vegetable with peppery-tasting leaves. It will grow from 30 to 46 cm tall. It is often eaten in salads. The flowers and seeds are also edible. It prefers full sun to partial shade and tolerates wet soil and light frosts.
I. Appearance and Characteristics
Rocket, eruca, or arugula (Eruca vesicaria; syns. Eruca sativa Mill., E. vesicaria subsp. sativa (Miller) Thell., Brassica eruca L.) is an edible annual plant in the family Brassicaceae used as a leaf vegetable for its fresh, tart, bitter, and peppery flavor. Its other common names include garden rocket (in Britain, Australia, South Africa, Ireland, and New Zealand), as well as colewort, roquette, ruchetta, rucola, rucoli, and rugula.
E. vesicaria is native to southern Europe, North Africa and the Middle East. As an invasive species arugula is widespread but scattered though is prolific and noxious in the Sonora desert of Arizona and California.
The species typically grows on dry, disturbed ground. It is a source of food for the larvae of some moth species, including the garden carpet. Its roots are susceptible to nematode infestation.
Eruca vesicaria is an annual plant growing to 20 to 100 cm (8 to 40 in) in height. The pinnate leaves are deeply lobed with four to ten, small, lateral lobes and a large terminal lobe. The flowers are 2 to 4 cm (3⁄4 to 1+1⁄2 in) in diameter, arranged in a corymb, with the typical Brassicaceae flower structure. The petals are creamy white with purple veins, and the stamens are yellow. The fruit is a siliqua (pod) 12 to 25 mm (1⁄2 to 1 in) long with an apical beak, containing several seeds. The species has a chromosome number of 2n = 22.
II. Types of Arugula
The types of arugula vary in flavor, appearance, and more. Here are some favorites:
- ‘Astro II’ is good for those who prefer a mild arugula flavor. This variety matures in as little as seven weeks.
- ‘Apollo’ is another mild variety. It is relatively heat-tolerant and has oval leaves.
- ‘Olive Leaf’ is better known by Italian speakers 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.
III. How to Grow and Care
Sunlight
Arugula grows best in full sun, meaning at least six hours of direct sunlight on most days. It also does well in part-sun, especially in warm climates. But as the temperature starts to rise, provide some afternoon shade. This will help to prevent the plants from wilting and bolting (flowering and going to seed), extending your harvest for as long as possible.
Temperature and Humidity
The ideal temperature range for arugula is between 45 and 65 degrees Fahrenheit. It tolerates frost but doesn’t like the high heat of summer. You can extend arugula’s growing season somewhat by protecting it from freezes with row covers and from heat with shading. But the best strategy is to plant it at the right times. It does not need high humidity and grows quite well in arid climates, provided it gets enough water.
Watering
Originating from a Mediterranean climate, arugula thrives in conditions that mimic its native coastal and submontane regions, where the soil moisture is relatively consistent. As such, arugula exhibits a preference for regular hydration but can withstand short periods of dryness. Watering every week will maintain its optimal growth balance. Typically cultivated outdoors due to its love for full sun exposure, arugula benefits greatly during its growing season from rainwater, which provides natural irrigation and supports its robust leaf production.
Soil
Arugula plants are happiest in well-drained soil with a slightly acidic to neutral soil pH. They tolerate a variety of soil types but prefer a nutrient-rich loam.
Fertilizing
For optimal health, arugula thrives with regular fertilization using high nitrogen fertilizers, ideal for leafy growth. Apply a balanced, water-soluble blend monthly during the growing season; a lighter dose is preferable to prevent nitrogen burn. Fertilizing arugula enhances vigor, increases yield, and improves flavor. Seasonal variations dictate adjusting the frequency: reduce applications as growth slows in cooler months. Always water arugula before fertilizing to protect roots. A well-fertilized arugula is robust and productive, offering gardeners a bountiful harvest.
How to Grow in Pots
Arugula plants are relatively small and self-contained, so they’re easy to grow in containers. This is a convenient way to keep your plants near your kitchen for regular harvesting. Also, as the weather warms, containers make it easy to move the plants out of direct sun in the heat of the day, thereby extending the growing season.
Because the roots are fairly shallow, you don’t need an exceptionally deep container. A depth of at least 6 inches with a wider diameter should do. Make sure the container has drainage holes. Unglazed clay is a good material to allow excess soil moisture to evaporate through its walls. And a self-watering container can make care a lot easier.
Pruning
No pruning beyond regular harvesting is necessary for arugula. But if you notice any broken or diseased leaves, remove them as soon as possible to help prevent problems from spreading.
Propagation
The most effective way to propagate arugula is by saving seeds. This is an inexpensive and convenient way to propagate varieties you particularly liked or plants that were especially vigorous. You just need to make sure different varieties are separated by at least 800 feet to avoid cross-pollination. Here’s how to save seeds:
- Allow your arugula plants to flower, and wait for the seed heads to turn brown and become brittle.
- Cut the seed heads off the plants, place them into a paper bag, and put them in a cool, dry spot to finish drying completely.
- Rub the seed pods between your hands to release the tiny black seeds. Separate out all the other plant matter. Doing this over a white sheet is helpful to see and catch everything.
- Store the seeds in a paper envelope or a jar. They should be viable for up to six years.
How to Grow From Seed
Most gardeners start arugula from seed. It can be direct-seeded in the garden starting about one to two weeks before the final frost in the spring. The seeds can germinate even when the soil temperature is as low as 40 degrees Fahrenheit. Lightly cover the seeds with soil, and keep the soil evenly moist but not waterlogged. Germination should occur within a week. Once the seedlings emerge, thin them to around 6 inches apart, saving the baby greens you think for eating.
Potting and Repotting
A quality all-purpose, well-draining, organic potting mix should work fine for potting arugula. Aim to pot your plants in a container that’s large enough for their mature size, so you can avoid repotting and disturbing them as they quickly mature.
Overwintering
Arugula is an annual, so no overwintering is necessary. You might be able to grow plants indoors over the winter if you can provide them with enough light. Grow lights are an option to supplement natural sunlight.
Pests and Diseases
Diseases aren’t common with arugula plants. But bacterial leaf spot and powdery mildew might occur. Moreover, the short, early growing season of arugula means 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.
III. Uses and Benefits
- Ornamental uses
Arugula is a popular edible species often grown in vegetable gardens to be harvested for salads and other dishes. This species is valued for its quick growth rate and for the distinctive taste of its leaves.
- Culinary uses
Since Roman times in Italy, raw arugula has been added to salads. It often is added as a garnish to a pizza at the end of or just after baking. In Apulia, in southern Italy, arugula is cooked to make the pasta dish “cavatiéddi”, “in which large amounts of coarsely chopped rocket are added to pasta seasoned with a homemade reduced tomato sauce and pecorino”, as well as in many recipes in which it is chopped and added to sauces and cooked dishes or in a sauce (made by frying it in olive oil with garlic). It also is used as a condiment for cold meats and fish. Throughout Italy, it is used as a salad with tomatoes and with either burrata, bocconcini, buffalo, and mozzarella cheese. In Rome, “rucola” is used in “straccetti”, a dish of thin slices of beef with raw arugula and Parmesan cheese.
In Turkey, similarly, the plant is eaten raw as a side dish or salad with fish or is served with a sauce of extra virgin olive oil and lemon juice.
In Slovenia, arugula often is combined with boiled potatoes or used in a soup.
In West Asia, Pakistan, and northern India, Eruca seeds are pressed to make taramira oil, used in pickling and (after aging to remove acridity) as a salad or cooking oil. The seed cake is also used as animal feed.
From about the 1990s arugula has become more popular in America, especially in trendier restaurants and in urban areas
IV. Harvesting and Storage
Your arugula should be fully grown and ready to harvest in about four to seven weeks, depending on the variety. It’s best to harvest leaves when they reach around 3 inches long. Young leaves are tender and sweet while older leaves start to get tough and bitter.
If you want the plants to continue to grow, collect just the outer leaves by cutting or tearing them off toward the base, leaving the crown intact. Alternatively, you can cut off all the leaves just above the soil; the plant might regrow if the weather is still mild. If you wait too long to harvest and the plant bolts, eat the flowers but not the leaves. The blooms appear after the leaves have grown to full size and are too bitter to eat. You can pick them off and add them to a salad or sandwich for a peppery bite.
Aim to use fresh leaves as soon as possible. They will keep in the refrigerator for up to a week.
