To grow microgreens indoors, start with clean, draining trays, a food-safe growing medium, seeds intended for edible greens, and reliable light after germination. Sow evenly, keep the medium damp without leaving water standing, and harvest with clean scissors when the crop reaches the leaf stage you want. The exact timing varies by crop and conditions.
A sunny window may work, but a grow light gives you more consistent light when days are short. Start with one tray of radish, broccoli, or pea shoots so you can learn how your room affects moisture and growth before adding more.
What do you need for one indoor tray?
- A shallow food-safe tray with drainage holes and a second tray to catch water.
- Fresh growing medium suitable for edible crops, such as a seed-starting mix or a clean growing mat.
- Seeds sold for growing edible microgreens. Check the supplier’s handling and crop instructions.
- Clean drinking water, a light source, and clean scissors for harvest.
Penn State Extension’s home-growing guide recommends clean containers with drainage. A reusable tray is fine if you wash and sanitize it between crops. For crop choices and flavor differences, see our beginner microgreens varieties guide.
How do you plant microgreens indoors?
- Prepare the tray. Fill it with a modest, even layer of damp growing medium. Let excess water drain.
- Sow the seed. Spread it evenly according to the crop and supplier’s suggested density. Crowding makes airflow and watering harder to manage.
- Help germination. Some crops benefit from a short cover or a light press; larger seeds may need soaking. Follow the instructions for your specific seed rather than using one method for every variety.
- Move into light. Once seedlings emerge, remove any cover and give them steady light. Rotate a window tray if it leans toward the glass.
- Check moisture daily. Water when the growing medium needs it, then drain the catch tray. Bottom watering can keep excess water off the leaves.
Seed size, density, temperature, and light change the schedule. Penn State’s step-by-step guide shows how different crops progress from sowing to harvest, so use plant appearance alongside the calendar.
How much light and water do microgreens need?
Give emerged seedlings bright light and watch for pale, stretched stems, which can signal that a window is too dim or the light is too far away. Follow your light manufacturer’s placement and operating guidance. Keep electrical equipment clear of spills.
There is no universal “water once a day” schedule. Check the medium with a clean finger; water enough to keep it damp, then let it drain. If water collects around stems, improve drainage and airflow. Penn State recommends avoiding excess moisture and, where practical, watering from below to limit contact with the edible leaves.
When should you harvest and store the greens?
Harvest when the leaves and stems suit the crop and the way you plan to use it. Many crops are cut around the cotyledon or first true-leaf stage; the number of days varies. Use clean scissors or a sharp knife and cut above the medium. Keep soil out of the harvest container.
For the best texture, cut shortly before eating. If you store a harvest, refrigerate it promptly and wash in fresh drinking water before use. Washing before storage can shorten the shelf life of these delicate greens, according to Penn State Extension. Discard greens that smell off or show visible spoilage.
What if seeds do not sprout or mold appears?
- Patchy germination: Check the seed date, sowing density, moisture, and crop-specific soaking instructions.
- Leggy seedlings: Increase usable light after emergence and check how far the fixture sits above the canopy.
- Persistent wetness or visible mold: Stop using the affected tray. Clean the tray and tools, begin again with fresh medium, and adjust drainage, density, and airflow.
Microgreens are commonly eaten raw, so cleanliness matters. Use potable water, clean tools and trays, and a medium appropriate for edible crops. Penn State’s food-safety guidance for microgreens explains how water, seed, growing medium, and handling can introduce contamination. If you plan to sell a harvest, review the applicable local food-safety rules before scaling up.
What should you grow next?
Try a second tray with a different flavor or germination pattern, then stagger sowing only after you know how much your household uses. Our seed-buying guide helps with sourcing. For a different growing method, read how to grow microgreens without soil.
