Are microgreens the same as sprouts?

No. This guide grows seedlings in a growing mix and harvests only the stems and leaves above it. Sprouts are usually eaten with the roots and seed. Do not treat this tray as a jar-sprouting method.

Is the white fuzz root hairs or mould?

Root hairs form close to individual roots; mould may spread over seeds or mix and accompany decay. Appearance alone is not a reliable safety test. If unsure, or if growth is slimy or smells bad, discard the batch rather than taste it.

Why are the seedlings tall and pale?

They may lack light or have stayed covered too long. Remove the cover after emergence, use a brighter position without overheating and supplement with a grow light for about 16 hours daily if needed. Follow the light maker's distance instructions.

Will the cut plants regrow, and how should I store the harvest?

Radish microgreens are normally a one-cut crop; start again with fresh seed and mix in clean trays. Dry rinsed greens well and refrigerate promptly at 4 °C (40 °F) or below. Use within a few days and discard spoiled greens sooner; refrigeration does not make a contaminated batch safe.

Guides/Garden/How to Grow Microgreens on a Windowsill

How to Grow Microgreens on a Windowsill

Grow a small tray of radish microgreens from seed to harvest on a bright windowsill. Allow about 20 minutes to set up, brief daily care and roughly 7–21 days to harvest, depending on the seed and conditions.

Updated Oct 2, 2026

20 min5 stepsBeginnernew

What you need

Tick off what you already have.

Tools

Shallow growing tray with drainage holes, about 15 × 20 cm (6 × 8 in)
Matching watertight catch tray
Clean spray bottle
Clean sharp scissors
Clean food container and paper towel
Optional grow light and timer if daylight is insufficient

Materials

Untreated radish seeds sold for microgreens; use the packet's sowing rate for your tray area
Fresh seed-starting mix suitable for edible crops; enough for a 2.5 cm (1 in) layer
Drinking-quality water

Hands filling a shallow black growing tray with fresh seed-starting mix beside a window

AI illustration

Step 01 / 05

Prepare a clean tray and growing mix

Wash your hands, tray and tools, then rinse well. Set the draining tray inside the catch tray. Add fresh seed-starting mix to a depth of 2.5 cm (1 in). Moisten it evenly so it feels damp, not dripping, and level the surface without packing it down. Use untreated radish seeds intended for microgreens, not chemically treated garden seed. Do not use garden soil or add fertiliser.

Guide progress1 / 5

1. Prepare a clean tray and growing mix
Instructional illustration generated with AI for Howmigo.
Wash your hands, tray and tools, then rinse well. Set the draining tray inside the catch tray. Add fresh seed-starting mix to a depth of 2.5 cm (1 in). Moisten it evenly so it feels damp, not dripping, and level the surface without packing it down. Use untreated radish seeds intended for microgreens, not chemically treated garden seed. Do not use garden soil or add fertiliser.
2. Sow the radish seeds evenly
Instructional illustration generated with AI for Howmigo.
Follow the seed packet's rate for your tray area. Scatter seeds evenly in a single layer without piles, press them gently onto the damp mix and mist lightly. Radish seeds usually need no soaking; follow the packet if it specifies otherwise. Cover with a clean loose lid or spare tray for germination, following any packet instructions on covering depth. Label with the sowing date.
3. Keep moist until the seeds sprout
Instructional illustration generated with AI for Howmigo.
Keep the tray around 21–24 °C (70–75 °F), away from radiators and hot direct sun. Check daily and lift the cover to let fresh air in. Mist only when the surface begins to dry; never leave it waterlogged. Remove the cover once seedlings emerge, usually after a few days. If you see spreading mould, smell decay or find slimy seedlings, discard the whole batch and clean the equipment.
4. Give light and water from below
Instructional illustration generated with AI for Howmigo.
Place the uncovered tray on a bright windowsill without overheating it. Rotate it daily for even growth. If seedlings become pale and stretched, add a grow light for about 16 hours a day, at the maker's recommended distance. When the mix starts to dry, add a little water to the catch tray; let it soak upward until the surface is damp, then pour off the excess. Keep leaves dry and allow airflow.
5. Harvest, rinse and start a fresh batch
Instructional illustration generated with AI for Howmigo.
Harvest when the seed leaves have opened and the first true leaves start appearing, often 7–21 days after sowing; follow the packet and plant development. Wash hands and scissors, then cut stems just above the mix without taking roots or soil. Rinse the cut greens under cool running drinking-quality water, pat dry and eat promptly or refrigerate at 4 °C (40 °F) or below. Discard slimy, mouldy or foul-smelling greens. For the next crop, clean the trays and use fresh mix and seed.