Microgreens are young vegetable greens harvested shortly after the cotyledon leaves have fully developed, representing an intermediate growth stage between a sprout and a mature plant. This brief cultivation period, typically lasting 7 to 21 days, allows the greens to concentrate high levels of nutrients. Scientific analysis shows microgreens contain significantly higher concentrations of vitamins, minerals, and antioxidants compared to their mature counterparts. They are cultivated indoors, allowing for year-round production and a consistent source of fresh produce.
Essential Supplies and Setup
Cultivation requires shallow growing trays, ideally a two-part system. One tray should feature drainage holes, and a second solid tray should sit beneath it. The solid tray catches excess water and facilitates bottom-watering in later stages.
The choice of growing medium is important, as microgreens do not require a deep layer of substrate. Fine-grain, sterile mediums like coco coir, peat-based mixes, or specialized hydroponic hemp mats are preferred. These mediums retain moisture well and reduce the risk of soil-borne pathogens. Specialized, untreated seeds are necessary, as standard garden seeds may not be safe for the high-density planting method used.
A simple artificial light source, such as full-spectrum LED or fluorescent shop lights, is needed for proper development after germination. The setup does not need to be elaborate, but light is required. A basic hand-held spray bottle is necessary to gently moisten the seeds and medium without disturbing the surface or displacing seeds.
Sowing the Seeds and Initial Germination
Successful growth relies on proper preparation of the growing medium before sowing. The medium should first be moistened thoroughly, aiming for a damp but not saturated consistency crucial for triggering germination. Seeds are then densely broadcast across the surface of the prepared medium, unlike traditional gardening where spacing is required.
The seeds should not be covered with additional soil, but they should be pressed lightly into the medium to ensure good contact and consistent moisture absorption. For varieties with larger seeds, such as sunflowers or peas, soaking them for 8 to 12 hours before planting can accelerate germination. Maintaining high humidity is achieved by misting the seeds immediately after sowing.
Following planting, the tray enters the “blackout period,” typically lasting two to four days. Covering the tray completely or placing it in a dark environment encourages seedlings to stretch as they search for light, resulting in strong, elongated stems and uniform crop height. This phase allows root systems to develop robustly before the plants create green foliage.
Active Growth and Harvesting Techniques
The blackout phase concludes when seedlings reach one to two inches in height and show the first signs of yellowing, indicating they are ready for light. Trays are then moved under the artificial light source, receiving 12 to 16 hours of light daily. This initiates photosynthesis and greens up the cotyledons. Proper light spectrum and intensity are important for producing vibrant color and preventing the plants from becoming weak or “leggy.”
Watering techniques must shift during active growth to prevent fungal issues like mold or damping-off, which thrive in high surface moisture. Growers transition to bottom-watering instead of misting from above. Water is poured into the solid tray beneath the drainage tray, allowing the medium to wick water up to the root zone without wetting the delicate stems and leaves.
Microgreens are ready to harvest once the cotyledon leaves are fully expanded, and before or just as the first true leaves begin to appear. Depending on the variety, this window is 7 to 14 days after sowing, though some can take up to 21 days. The harvest is a one-time event because removing the growing point prevents re-growth.
Harvesting is performed using clean, sharp scissors or a knife to cut the stems just above the soil line. This technique ensures a clean product free from the growing medium while maximizing the edible portion. After cutting, the microgreens should be gently rinsed, dried thoroughly, and stored in an airtight container under refrigeration.