Microgreens are the edible seedlings of various vegetables and herbs, harvested shortly after the first set of true leaves emerges. These young plants are distinct from sprouts because they are grown in soil or a growing medium and only the stem and leaves are consumed. Their popularity has surged due to their concentrated flavor profiles, ranging from spicy to sweet, and their high density of vitamins and antioxidants compared to mature plants. Growing these nutrient-dense crops at home provides a fresh, year-round source of greens right from your kitchen counter.
Essential Supplies and Setup
You will need shallow growing containers, about two inches deep, with small drainage holes to prevent waterlogging of the medium. For the substrate, choose a sterile growing medium like fine-grade coconut coir, peat moss, or a professional seed-starting mix. Sterility minimizes the risk of introducing pathogens that could harm the delicate seedlings.
Selecting the right seed requires high-quality, untreated seeds specifically labeled for microgreen production. Common varieties include radish, broccoli, and sunflower, which offer reliable germination rates and robust flavor. Locate your setup near a south-facing window for maximum natural light, or prepare a dedicated shelf with supplemental lighting. The chosen area should maintain a consistent room temperature, ideally between 65°F and 75°F, to promote steady growth.
Sowing Seeds and Initial Germination
Prepare your growing tray by filling it with the chosen sterile medium, leveling the surface without compacting it too firmly. The medium should be pre-moistened to the consistency of a wrung-out sponge before broadcasting the seeds. Achieving the correct seed density is paramount for a uniform crop, requiring seeds to be scattered evenly and densely across the medium. Gently mist the seeds with a spray bottle to settle them in, avoiding any displacement. This light misting provides the necessary surface moisture for germination.
The next step is the “blackout” period, covering the tray with another tray or a dome for three to five days. Keeping the seeds in complete darkness encourages them to germinate and stretch uniformly as they seek light. This process, known as etiolation, promotes longer stems and a more tender texture before they are exposed to light. Once the seedlings have reached about an inch in height, they are ready to transition to the light stage.
Managing Light, Water, and Airflow During Growth
Once the blackout phase is complete, transfer the microgreens to a location with sufficient illumination to initiate photosynthesis. While a bright window may suffice for some varieties, supplemental lighting is usually required to prevent legginess and ensure deep green color development. Low-cost LED or fluorescent shop lights are effective, often positioned approximately four to six inches above the tops of the seedlings.
Maintaining a consistent light cycle is achieved by providing the plants with about 12 to 16 hours of light per day. This extended photoperiod ensures the rapid production of chlorophyll and necessary sugars for growth. The light intensity, measured in photosynthetic photon flux density (PPFD), does not need to be as high as for fruiting plants, but consistency is a stronger factor for successful microgreen growth.
The method of delivering water is crucial for preventing common issues like fungal growth and damping off. Instead of overhead watering, employ bottom watering. This technique involves placing the growing tray into a larger, shallow reservoir of clean water for about 15 to 30 minutes.
The growing medium absorbs water from the bottom, ensuring the roots are hydrated while keeping the surface dry. This is typically done once every one to two days, depending on the ambient humidity and how quickly the medium dries out. Only remove the tray from the reservoir once the top surface of the medium appears moist.
Proper air circulation is important for discouraging pathogens and strengthening the plant stems. Stagnant, humid air creates an ideal environment for mold spores to proliferate on the dense canopy of greens. A small oscillating fan directed across the trays for several hours each day will help to gently move the air and maintain a healthy microclimate. This constant, gentle movement also helps to slightly stress the stems, resulting in thicker, more robust plants that stand upright.
Harvesting Techniques and Storage
The microgreens are generally ready for harvest when they have developed their first set of true leaves, which appear after the initial, rounded cotyledon leaves. This stage, typically reached within 7 to 21 days from sowing, signifies the peak of their flavor and nutritional profile. Waiting until the true leaves emerge ensures the maximum accumulation of flavor compounds and phytonutrients within the plant tissue.
To harvest, use a pair of clean, sharp scissors or a knife to cut the stems just above the surface of the growing medium. It is important to avoid cutting into the medium itself, as this can introduce soil particles into your harvest. Cutting just above the soil line yields the cleanest product and maximizes the stem length.
Microgreens should be consumed immediately for the best flavor and nutritional benefit, but they can be stored short-term. If you need to store them, do not wash them until you are ready to eat them. Place the unwashed greens loosely into an airtight container or a paper towel-lined bag and refrigerate them. When stored properly, they will retain their freshness for approximately three to five days.