Arugula is a fast-growing, cool-weather crop well-suited for a controlled home environment. It prefers the moderate temperatures typically found inside a house rather than the intense heat of a summer garden. Its rapid growth cycle allows for a harvest in as little as 30 to 40 days from seeding, making it ideal for a continuous supply of fresh, peppery greens. Since it does not require extensive root depth, arugula thrives in smaller containers and responds well to indoor setups.
Creating the Ideal Indoor Environment
Replicating the strong, consistent light arugula needs is crucial for producing robust leaves. Arugula requires the equivalent of a full day’s sun exposure, meaning you must provide between 12 and 14 hours of light daily. If placing the plant near a sunny, south-facing window, supplement with artificial lighting, especially during winter months when natural light intensity is low.
Full-spectrum LED grow lights are highly effective and energy-efficient, emitting the necessary wavelengths for photosynthesis. Position these lights approximately six to twelve inches above the plants, adjusting the height as the arugula grows to prevent leaf burn.
Temperature regulation is equally important, as arugula performs best when the ambient air remains between 60 and 70 degrees Fahrenheit. Temperatures consistently rising above 75 degrees Fahrenheit can trigger the plant to “bolt,” causing the leaves to develop a bitter taste. Avoid placing containers near heat vents or hot appliances that could stress the plant.
Proper container selection is also necessary, requiring a pot with adequate drainage holes. A depth of at least four inches will accommodate the shallow root system, though a six-inch depth generally yields larger leaves.
Planting and Ongoing Care
A well-chosen growing medium is necessary for maintaining the consistent moisture levels arugula requires. Use a light, well-draining potting mix, which often includes perlite or vermiculite to prevent compaction and ensure adequate root aeration. Coconut coir-based mixes are also favored due to their excellent moisture retention while still allowing for good drainage.
Sow the seeds about one-quarter inch deep, or press them gently onto the surface of the pre-moistened soil, spacing them one to two inches apart. After seedlings emerge, thin them by removing the weaker plants to ensure the remaining arugula has room to mature. The soil should feel damp like a wrung-out sponge, but never waterlogged, as this can quickly lead to root rot.
Once the plants are established and have developed their first set of true leaves, introduce a diluted liquid fertilizer. A balanced blend, such as a 10-10-10 NPK formulation, applied at half strength every two to four weeks, supports vigorous leaf production. Water gently at the base of the plant to maintain moist conditions and avoid splashing water onto the foliage, which can encourage disease.
Harvesting for Continuous Yield
Use the “cut-and-come-again” technique to encourage the plant to produce new leaves for an extended period. Once the leaves are four to six inches tall, use clean scissors to trim the outer, more mature leaves, leaving the smaller, central leaves untouched. Never remove more than one-third of the plant’s total foliage at any single harvest, as the remaining leaves are necessary for continued growth.
A common indoor issue is bolting, where the plant prematurely sends up a seed stalk, often caused by high temperatures or inconsistent watering. The moment a central stalk appears, harvest all remaining leaves immediately, as the flavor becomes intensely bitter shortly after the plant flowers.
If you notice small, fuzzy insects like aphids, a gentle spray of insecticidal soap or a wipe-down with a cotton swab dipped in neem oil solution can resolve the infestation. Small, dark, flying insects near the soil are likely fungus gnats, a sign of overly wet potting mix. To manage them, allow the top inch of soil to dry out between waterings and consider applying a thin layer of diatomaceous earth.