How to Grow Microgreens
Microgreens are young edible seedlings grown quickly indoors for their fresh flavour and colour. They need little space, making them ideal for a bright windowsill throughout the year. With clean trays, peat-free compost, suitable seed and steady moisture, most crops are ready to cut in around one to three weeks.
Choose seeds sold for sprouting or microgreen growing, or untreated vegetable seed intended for eating. Reliable beginner choices include radish, rocket, pea shoots, mustard, coriander, kale and beetroot. Avoid seed that has been treated or labelled only for ornamental use. Use a shallow tray with drainage holes, plus a waterproof tray beneath it to protect the windowsill. Wash reused trays thoroughly and allow them to dry before filling. Microgreens need bright light after germination, but do not need a heated propagator in a warm home. Select a clean, bright windowsill away from cold draughts and radiators. Start one or two trays at a time until you learn how quickly your household uses them.
Fill the tray with 3 to 4 cm of moist peat-free multipurpose compost, then level it gently without compressing it heavily. Scatter seed evenly over the surface. Peas need more space than fine brassica seed, so avoid forming a thick mat where air cannot move. Press seed lightly into the compost and cover only if the packet suggests it; many small seeds germinate well with a very thin covering. Mist or water gently so seed stays in place. Label the tray with crop and sowing date. Cover it loosely with another tray, a clean lid or paper until germination begins, checking daily so emerging shoots do not become pale and stretched.
Move trays into strong natural light as soon as shoots appear, usually after a few days. Turn them every day or two so stems grow upright rather than leaning towards the window. In dark winter weather, choose the brightest position available and expect growth to take longer. Keep the room comfortably cool rather than hot, because excessive warmth and poor ventilation encourage weak growth and mould. Give trays some air movement, but protect them from cold window glass at night. If seedlings become tall and floppy, they need more light. If they are crowded and damp, sow less thickly next time and improve airflow rather than trying to rescue an overcrowded tray.
Water carefully from below whenever the compost surface begins to lose moisture. Pour a small amount of water into the waterproof base tray, let the compost absorb it for a few minutes, then empty any standing water. This keeps stems drier and reduces the chance of mould. If top watering is necessary, use a fine spray or a gentle pour around tray edges. Never allow compost to become bone dry, especially during germination, but avoid constant saturation. Check every day because a sunny windowsill can dry a shallow tray rapidly. If you see mould, remove affected material, improve air circulation and clean trays before the next sowing.
Harvest when the first pair of seed leaves is fully open and, for many crops, before the first true leaves become large. This is often seven to ten days for radish and rocket, while peas and coriander may take longer. Use clean scissors to cut a small handful just above the compost surface. Harvest immediately before eating for the best texture. Do not pull plants from the tray, as compost can cling to stems. Rinse only if necessary, then dry gently. Most microgreen trays give one good cut rather than repeated harvests. Add the spent compost and roots to the compost heap or bin if they are healthy.
Keep a simple rotation so fresh trays are always approaching harvest. Sow a new tray every four to seven days, varying crops for different flavours and colours. Wash scissors, trays and waterproof bases between batches, particularly if a tray has shown mould. Use fresh peat-free compost rather than reusing a dense root mat indoors. In summer, keep trays out of harsh midday sun, which can dry seedlings within hours. In winter, sow a little less densely and accept slower growth. Once you have reliable results, try pea shoots for a substantial crop or coriander for a slower, aromatic one, while maintaining the same clean, evenly moist routine.
Frequently asked questions
Do microgreens need direct sunshine?
They need bright light after germination, but scorching direct sun can overheat and dry a shallow tray. A bright windowsill is usually sufficient, especially in spring and summer. Turn trays regularly for even growth. In dim winter conditions, growth will be slower and seedlings may stretch, so use the brightest available indoor position.
Why is white mould appearing on my tray?
Mould is usually encouraged by overcrowding, excessive moisture, warmth and stale air. Remove affected seedlings, improve ventilation and let the surface dry slightly between waterings. Water from below where possible. Thoroughly clean trays before the next batch and sow more thinly. Some fine root hairs can look fuzzy, so check whether they are attached only to roots.
Can I regrow microgreens after cutting them?
Most microgreens are best treated as a single-cut crop. After cutting, the remaining stems have limited energy and may regrow unevenly, especially in a shallow compost layer. Pea shoots sometimes give a modest second cut, but quality varies. For dependable harvests, compost the old tray contents and sow a fresh one.
General guidance for UK home gardens and allotments. Conditions vary by region, soil and season; the RHS or a local garden centre can give site-specific advice. Page updated 19 Sep 2026.