Skill guide · Water & Food

Microgreens

Not a smaller version of a full-grown vegetable, a genuinely different crop: seeds grown to the point their first true leaves are just emerging, then harvested, at 7–14 days from seeding rather than weeks or months. That speed and the minimal setup it needs make microgreens worth knowing regardless of which growing method the rest of a household's food comes from. This guide covers seed density, watering method, light, and harvest technique alongside the timing and variety choice, not just the concept.

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Setup: shallow, simple, and fast to start

A shallow tray, 2–3 inches deep, with drainage holes, over a simple growing medium (a thin layer of potting soil, or a reusable mat) is the entire setup. No pollination, no deep root system, and no months-long commitment to a single planting; a failed or finished tray costs a week, not a season.

VarietyDays to harvestWhy this one
Radish or mustard 5–7 days The fastest options, and both brassicas, the same nutrient family already worth growing per What to Grow's secondary-crop table
Broccoli 7–10 days A middle-speed option with a mild flavor most households find easier to use regularly
Sunflower or peas 10–14 days Slower, but a real texture and flavor difference worth growing alongside the faster brassicas rather than instead of them

Harvest right at the point the first true leaves are just emerging above the seed leaves (cotyledons), not before and not much after; this is when flavor and nutrient concentration actually peak, not an arbitrary cutoff.

Warning

Don't grow microgreens from a general garden seed packet

Many seeds sold for outdoor planting are treated with a fungicide (thiram, captan, and metalaxyl are common ones), usually dyed pink, blue, or purple as a visual warning that they're not for consumption. That treatment matters far more here than it would in a garden bed: microgreens are harvested just 7–14 days after germination, in a warm, moist environment that actually favors chemical absorption into the young seedling, with none of the months a normal crop has for residue to break down before harvest. Buy seed sold specifically for sprouting or microgreens production instead; it's untreated and handled under food-safety standards a general garden seed packet isn't.

Seeding, watering, and light: the three details that make or break a tray

Seed density matters more here than in almost any other growing method on this site: sow far more thickly than a normal vegetable planting, close enough that seeds nearly touch, roughly 8–10 oz of small brassica seed like radish or mustard per standard 10x20 tray, or about 1.5–2 tablespoons of very fine seed for a smaller tray, then start at the low end and adjust up or down based on how a given tray actually performs. A humid, low-airflow room supports less seed per tray before mold becomes a risk; a brighter, better-ventilated space can carry more.

Water from the bottom, not the top: set the tray in a shallow pan of water and let it wick up through the drainage holes, or pour water into an outer tray the growing tray sits inside. At this seed density, water poured directly onto the seedlings pools between them and reliably causes mold; bottom watering keeps the foliage itself dry while still reaching the roots.

Light matters as much as it does for any other indoor crop: 6–10 hours a day of bright light, either a sunny window or a basic grow light, is enough for most varieties (the exception is corn shoots, which are grown fully in the dark until harvest to keep them tender and pale). Without enough light, microgreens stretch tall, pale, and thin, called legginess, rather than growing into a shorter, sturdier, more flavorful crop.

Harvest with clean kitchen scissors or a sharp knife, cutting just above the growing medium so soil or mat fiber doesn't come away with the greens; a single cut across the whole tray at once, rather than pulling individual plants, is both faster and cleaner.

Warning

The nutrient density is real, and it fades fast once cut

Microgreens genuinely carry 4 to 40 times the nutrient concentration of the same crop grown to full size, a real, measured difference, not marketing. That advantage starts dropping within 24 to 48 hours of harvest as the cut plant begins to oxidize, and even refrigerated, quality holds for only about 5 to 7 days. Treat a harvested tray as something to actually eat that week, not something to store the way a root cellar crop or a canned good works.

Why this belongs on this site regardless of method

Microgreens don't compete with any of the four growing methods already covered here, they slot alongside all of them. A soil tray on a counter works the same in a house with a full row-crop garden as in one with none at all. A walipini already extending a cold-hardy growing season has more than enough light and space to run trays through the parts of the year outdoor beds can't produce anything. And hydroponic systems, already good at leafy greens generally, handle microgreens on the exact same nutrient solution and equipment used for anything else grown there. In a genuinely short-notice situation, days to a first harvest instead of weeks or months is a real, practical advantage none of this site's other growing methods can match.

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