Microgreens are young edible seedlings of vegetables and herbs, harvested just after the first leaves, known as cotyledons, have fully developed. This stage, usually occurring within one to two weeks, captures a burst of flavor and a high concentration of nutrients often exceeding that of the mature plant. The jar method is an accessible, space-saving technique for growing these greens indoors, requiring minimal equipment and no soil. This approach simplifies cultivation, allowing anyone to grow fresh produce directly on a kitchen counter.
Essential Supplies and Seed Preparation
Cultivating microgreens in a jar requires only a few household items, primarily a wide-mouth glass jar for sufficient surface area and air exchange. A specialized sprouting lid with a mesh screen, or cheesecloth secured with a rubber band, is necessary for covering the opening. This permeable cover facilitates both draining water and allowing air circulation.
Varieties like radish, broccoli, clover, and alfalfa are excellent for the soil-less jar method due to their reliable germination rate. Seeds must be prepared by soaking them in cool water for 4 to 12 hours. This process, called imbibition, breaks dormancy by allowing water to penetrate the seed coat and initiate germination. After soaking, the water must be completely drained, leaving the seeds damp.
Step-by-Step Jar Setup and Germination
Once the seeds are soaked and drained, transfer them back into the jar for the germination phase. Spread the seeds relatively evenly along the interior surface, then secure the mesh lid or cheesecloth over the opening.
The initial stage requires a dark environment for approximately two to three days, known as the blackout phase. This encourages the root structure to develop and the seedling stems to stretch out as they search for light. During this period, the developing seeds must be rinsed and drained one or two times daily.
Rinsing involves gently filling the jar with cool water, swishing it around to moisten the seeds, and immediately pouring the water out through the mesh cover. This action removes metabolic waste products and provides hydration. Complete draining is essential, as residual water creates a stagnant, high-humidity environment that breeds mold and bacteria.
Maintaining Growth, Harvesting, and Common Issues
After the initial germination phase, when small rootlets are visible, move the jar to a location with indirect sunlight or under a dedicated grow light. This transition triggers photosynthesis, causing the tiny leaves to turn green as the seedlings develop their cotyledons.
The daily routine of rinsing and draining must continue throughout the growth phase until harvest, ensuring the microgreens are hydrated without sitting in standing water. Once the microgreens have grown one to two inches tall and the cotyledons are fully open (7 to 14 days after planting), they are ready for harvest.
To harvest, cut the greens using clean scissors, snipping the stems just above the root mass. Microgreens are harvested by separating the aerial part of the plant from the root structure. The most frequent challenge is the appearance of white, fuzzy mold, often mistaken for root hairs. Prevention focuses on maximizing airflow and ensuring superior drainage, as true mold tends to be slimy or grey.