Microgreens are one of the fastest, lowest-equipment crops you can grow indoors — most varieties are ready to harvest in as little as one to three weeks from a tray on a windowsill or under a light, with no garden bed, grow tent, or months of waiting required. All you need is a shallow tray, a growing medium, seed, water, and a light source.
Below is the full process — what you need, choosing a growing medium, sowing and germinating, watering, and harvesting — followed by honest days-to-harvest guidance by variety and answers to the most common questions. If you’d rather skip the DIY setup and start from a complete kit, our best microgreens growing kits guide covers verified picks across both soil-based and hydroponic mechanisms.
What You’ll Need
The core list is short: a shallow tray or container with drainage, a growing medium (soil, coco coir, or a hydroponic growing mat), microgreens-specific seed, water, and a light source — a bright windowsill works for many varieties, though a small grow light gives more consistent results. That’s genuinely all it takes; microgreens don’t need the heat mats, tents, or months-long timelines that starting a vegetable garden from seed does. If you’d rather not gather and size each piece yourself, our best microgreens growing kits guide covers complete kits that bundle a tray, medium, and seed together.
Choosing a Growing Medium: Soil, Coco Coir, or a Hydroponic Mat
Every microgreens setup falls into one of two mechanically different approaches, and picking the right one matters more than picking a specific seed variety.
Soil or coco-coir trays are the more traditional approach: a shallow layer of seed-starting soil or compressed coconut coir holds moisture and gives roots something to anchor into. It’s forgiving of minor watering mistakes and doesn’t require a specialty growing surface, but it’s messier at harvest — you’ll rinse soil or coir off the cut stems — and needs fresh medium each time you resow the tray.
Hydroponic growing mats — typically bamboo fiber, hemp, or a similar fibrous pad — wick water up from a reservoir below, with no loose soil at all. Seeds root directly into the mat’s fibers. This produces a cleaner harvest with nothing to rinse off, but the mat itself is a recurring consumable, and even moisture distribution across the whole mat matters more than it does with a deeper soil layer.
Neither approach grows microgreens meaningfully faster than the other — the main difference is mess and cleanup at harvest, not speed or yield.
Step 1: Sow Seed Densely and Evenly
Unlike a vegetable garden, microgreens are sown thickly — you’re growing a dense carpet of seedlings, not individual widely-spaced plants. Scatter seed evenly across the surface of your growing medium until it’s densely and uniformly covered, with little bare medium showing through, then press seeds gently into contact with the medium (most microgreens seed doesn’t need to be buried). Uneven distribution is one of the most common reasons for a patchy, thin harvest, so take an extra minute to spread seed as evenly as you can before moving on.
Step 2: Cover and Blackout Through Germination
After sowing, mist the surface, then cover the tray — with a humidity dome, a second tray stacked upside down on top, or another light-blocking cover — for the first several days. This initial dark, humid period keeps moisture in during germination and encourages seedlings to grow upward toward where light would be, producing sturdier, more uniform stems once uncovered. Check daily and keep the medium consistently moist; check under the cover periodically once you see the seed coats crack, since the blackout period typically ends within the first few days to about a week, once most seedlings have emerged and are pushing up against the cover.
Step 3: Move Into Light Once Seedlings Emerge
Once seedlings have sprouted and are visibly pushing against the cover, remove it and move the tray into bright light — a sunny windowsill or a small grow light positioned a few inches above the tray. This is the point where seedlings green up and develop their first true leaves. Seedlings left in the dark too long after germinating will stretch into thin, pale, leggy stems, so don’t delay this step once you see consistent emergence across the tray.
Step 4: Water Carefully to Avoid Mold
Bottom-watering — setting the tray in a shallow reservoir and letting the medium wick moisture upward, or using a self-watering tray design — keeps the leaf surface dry, which is the single biggest factor in avoiding mold and damping-off in a dense microgreens tray. If you water from above, use a gentle mist rather than a heavy stream, and water in the morning so the surface has time to dry through the day rather than sitting damp overnight. Good airflow around the tray also meaningfully cuts mold risk, especially once the cover comes off.
Step 5: Monitor Growth Through Harvest
From here it’s mostly a waiting game: keep the medium evenly moist, keep the tray in consistent light, and watch for the first true leaves (the second set of leaves to appear, distinct from the initial rounded cotyledons). Most varieties are ready to harvest once those first true leaves have opened, which is also the point most sources define as the actual “microgreen” stage, as opposed to a sprout, which is eaten earlier with the root and seed hull still attached.
Days to Harvest by Variety
Total time from seeding to harvest varies by variety and growing conditions, but as a general guide, most common microgreens are ready somewhere between one and three weeks:
- Brassicas (broccoli, kale, cabbage, mustard): typically among the faster growers, often ready in about a week to ten days.
- Radish: also fast, frequently ready within a similar one-to-two-week window, with a noticeably peppery flavor.
- Sunflower: generally slower and bulkier-stemmed, often needing closer to two weeks, and benefits from a weighted cover during germination to help the hull shed cleanly.
- Pea shoots: also on the slower end, commonly closer to two weeks, valued for their crunchy texture and mild pea flavor.
These are typical ranges, not fixed timelines — your specific seed lot, indoor temperature, and light levels all shift the actual harvest date, so treat the first true-leaf stage described in Step 5 above as the real signal to harvest, not a fixed day count.
Harvesting and Handling Safely
Harvest by cutting stems just above the growing medium with clean scissors or a knife, once the first true leaves have opened. Rinse the cut greens gently and pat or spin them dry — excess moisture left on harvested microgreens shortens how long they’ll keep. Refrigerate promptly in a container lined with a dry paper towel, and use them within about a week for the best texture and flavor.
Start with seed sold specifically for sprouting or microgreens production, since it’s produced and handled to reduce the risk of microbial contamination, which matters more for a crop eaten raw and freshly cut than for seed grown to full maturity. Wash hands and clean your tray and tools between grows, the same basic hygiene practice you’d use with any fresh produce you plan to eat raw.
Frequently Asked Questions
Do microgreens regrow after you cut them?
Most microgreens are cut once, just above the growing medium, and don’t produce a meaningful second harvest from the same tray — the seedling is too young to regenerate the way a mature, established plant can. A handful of varieties (like pea shoots) can occasionally produce a light second cutting, but it’s inconsistent enough that it’s simplest to plan on one harvest per tray and resow.
Is it worth it to grow your own microgreens?
If you eat microgreens regularly, growing your own is usually the better value over time, since one batch of seed and medium typically produces several trays’ worth of harvests compared to buying a fresh store clamshell each time. The tradeoff is the one-to-three-week wait between sowing and harvest, plus a small amount of counter space and daily attention — if you only want microgreens occasionally, buying pre-grown may still be simpler.
Are there toxic microgreens to avoid?
Yes — nightshade-family seedlings, including tomato, potato, and eggplant, should not be grown or eaten as microgreens. They contain solanine and related glycoalkaloids that are toxic even though the mature fruit of the same plants is safe to eat. Stick to seed sold and labeled specifically for sprouting or microgreens production (common choices include brassicas, radish, sunflower, and pea shoots) rather than saved garden seed of unknown origin or type.
Is it better to grow microgreens in soil or water?
Neither is objectively better — soil or coco coir is more forgiving of watering mistakes and needs no specialty growing surface, while a hydroponic mat produces a cleaner harvest with nothing to rinse off but relies on even moisture across the mat. Growing speed and final yield are broadly similar between the two; the real difference is mess and cleanup at harvest.
How long does it take to grow microgreens indoors?
Most common varieties are ready somewhere between one and three weeks from sowing, depending on the variety, indoor temperature, and light. Faster growers like brassicas and radish often finish closer to one to two weeks, while sunflower and pea shoots typically take closer to two weeks — the reliable signal to harvest is the first true leaves opening, not a fixed calendar date.
Ready for the Next Step?
The process above works with basic supplies you likely already have on hand. If you’d rather start from a complete, verified kit instead of gathering a tray, medium, and seed separately, see our best microgreens growing kits guide for picks across both soil-based and hydroponic mechanisms.
General growing information above is provided for educational purposes. Seed variety, indoor conditions, and growing medium all affect actual timelines — treat the days-to-harvest guidance above as a starting point, not a guarantee.