key growing information

How to Grow Microgreens

How to grow microgreens: trays and media, sowing density, germination methods, watering, temperature, light, fertility, days to harvest, disease prevention, harvest and shelf life.

By Hensley’s Seed Co. September 3, 2026

Microgreens - Key Growing Information

Tray of microgreens, ready for harvesting.

CULTURE:

Grow microgreens in a greenhouse or other protected space. Check each variety's germination guidelines, but the brassica-family approach works for most: use potting mix or a soilless medium in shallow trays or 20-row flats. Scatter seed thickly over the surface, about 1/8–¼" apart, press it firmly into the medium for good contact, then cover lightly with sowing mix or vermiculite, or use a humidity dome. You can germinate microgreens on heat mats, in germination chambers, or right on greenhouse benches or floors.

WATERING:

Water from below or mist so the mix doesn't splash onto the seedlings. Keep moisture even and never let the medium dry out.

TEMPERATURE:

Hold the soil near 75°F (24°C) until germination, then drop it to about 60°F (16°C). Air temperatures vary by variety, but 65–75°F (18–24°C) generally works well; going above 75°F (24°C) can raise disease pressure and hold back germination.

LIGHTING:

Add grow lights wherever natural light falls short, such as a greenhouse in the short days of winter.

FERTILIZER:

In media that carry some fertility, such as potting mix, plain water usually works best. A weak fertilizer solution suits media with no nutrients of their own, or slow crops that might run through the available fertility before harvest. If you do fertilize, mix it into the sowing medium beforehand, or deliver liquid feed by bottom watering so nothing is left on the leaves.

DAYS TO MATURITY:

Timing depends on variety, conditions and the size you want. Fast growers are usually ready in 10–15 days, slower ones in 16–25 days.

DISEASES:

Dense sowing makes microgreens prone to problems like damping off, especially with poor airflow and waterlogged media. Keep air moving with horizontal airflow fans, use clean media and water, and sow at the right density.

HARVEST:

Harvest once cotyledons are fully open, or as the first true leaves start to show, depending on what your customers want. Most are cut at ½–2" tall. Use scissors or a sharp knife, and handle them as little as possible to avoid damage.

STORAGE:

Under good storage conditions they keep 5–10 days. Always wash microgreens before eating.