Selecting a Planting Site
Your planting site should be sunny to part-sunny and have well-draining soil. Container growth is also an option. Avoid planting where other members of the Brassicaceae family have been in the past year, as pests and diseases that affect the family at large might linger in the soil.
Spacing, Depth, and Support
Seeds should be planted roughly 1/4 inch deep and an inch apart in rows that are about a foot apart. Nursery plants should be positioned at the same depth they were in their previous container. A support structure won’t be necessary.
Arugula Plant Care
Light
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.
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.
Water
Like many vegetables, arugula needs regular watering for healthy growth and optimal flavor. It has a shallow root system. Keep the soil consistently moist but not soggy, watering as soon as the top inch of soil feels dry. In dry climates, this might mean watering every morning. If you fail to water regularly, you’ll likely cause the plants to bolt and ruin the flavor of the leaves.
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.
Fertilizer
As long as you plant your arugula in nitrogen-rich soil, it shouldn’t need additional feeding. Pale leaves indicate a lack of nourishment. To enrich your soil, mix in compost prior to planting.
Pollination
Arugula is a self-pollinator, and varieties also can cross-pollinate via insects and the wind.
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.
Arugula vs. Spinach
Arugula and spinach are commonly combined in salads, and interestingly they’re often substituted for one another in recipes even though they have quite different flavors and textures. Arugula is notably peppery, while spinach is mild and a little sweet. Spinach leaves also are generally fuller and lack the deep lobes of arugula leaves.
Harvesting Arugula
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.
How to Grow Arugula 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.
Propagating Arugula
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:
How to Grow Arugula 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 thin for eating.
Potting and Repotting Arugula
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.
Common Pests and Plant 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.
