Arugula is a fast-growing, cool-season green valued for its distinct peppery flavor. Often called rocket, this leafy vegetable can be ready for harvest in as little as four weeks. Success begins with understanding the planting process. Proper technique ensures strong germination and a sustained supply of tender leaves.
Preparing the Ground and Timing the Sowing
Arugula thrives in cooler temperatures, so timing the sowing is important. Ideal planting periods are early spring, as soon as the soil is workable, and late summer or early fall. Avoid planting during peak summer heat. High temperatures cause the plant to “bolt,” which makes the leaves taste overly strong and bitter.
Preparing the seedbed involves creating an environment that supports rapid growth. Arugula prefers loose, well-draining soil rich in organic matter. Incorporate compost into the planting area for adequate fertility and moisture retention. Once amended, rake the soil surface smooth to facilitate good seed contact.
The Critical Depth and Spacing Requirements
The depth at which arugula seeds are sown determines successful germination. Arugula seeds require light exposure to break dormancy and sprout, a characteristic known as being photoblastic. Therefore, they must be planted very shallowly, no more than one-quarter inch deep.
Gardeners can scatter seeds on the prepared soil surface and lightly press them in. Cover the seeds with a very thin layer of fine soil or vermiculite, ensuring they are not buried too deeply. Initial sowing should aim for approximately one inch between seeds.
This close initial spacing produces small, tender leaves suitable for a “baby greens” harvest. Planting seeds slightly deeper than the recommended one-quarter inch significantly inhibits germination, resulting in a sparse crop. Focusing on this shallow depth is paramount to successful sprouting.
Essential Post-Planting Care and Management
After sowing, maintaining consistent moisture is necessary for the shallowly planted seeds to germinate. Because the seeds are near the soil surface, they are susceptible to drying out quickly. Light, frequent watering is beneficial until the seedlings establish roots, ensuring the top layer of soil does not crust over.
Once seedlings develop their first set of true leaves and reach about an inch tall, thinning must begin. Thinning involves removing weaker seedlings to give remaining plants adequate space. For a full-sized harvest, seedlings should be thinned to a final spacing of four to six inches apart.
The small plants removed during thinning are edible and can be used immediately in salads. Managing pests is an ongoing task, with flea beetles often chewing small holes in the leaves. Using a lightweight row cover immediately after planting blocks these insects from reaching the foliage.
The harvest window typically opens four to six weeks after sowing. A continuous harvest is achieved using the cut-and-come-again method, where only the outer leaves are snipped off above the crown. This technique encourages the plant to produce new growth from the center, prolonging the yield. Regular harvesting and consistent moisture help delay bolting, extending the season of flavorful leaves.