How do I grow sprouting seeds and microgreens indoors?

These two get lumped together and they are genuinely different crops with different methods and different risks. Sprouting happens in the dark in water and the whole seedling including the root is eaten. Microgreens are grown in compost in the light and only the top is cut, which means the food safety questions that surround sprouts largely do not apply.

Safety

Step by step

1. Choose the right seed for the method.For sprouting, buy seed sold specifically for sprouting — mung bean, alfalfa, lentil, chickpea, radish, broccoli. Garden seed may be dressed with fungicide and is not intended for eating whole. For microgreens, ordinary vegetable seed is fine because you are not eating the seed or the root.
2. For sprouting, use a jar and a mesh lid.A jam jar with muslin and an elastic band, or a purpose-made sprouting jar. The essential feature is that it can be rinsed and then drained upside down at an angle so no water sits in the bottom.
3. Soak, then rinse twice a day.Soak the seed for several hours or overnight, drain, then rinse with fresh cool water and drain thoroughly morning and evening. Missing rinses is what turns a jar of sprouts into a food safety problem.
4. Keep the sprouting jar cool and out of direct sun.A kitchen worktop out of the sun is right. Warm sunlight plus damp seed accelerates bacteria as well as sprouts.
5. Harvest sprouts at three to five days and refrigerate.Rinse well, drain thoroughly, and keep in the fridge in a container for a few days. Use them promptly.
6. Use your nose and eyes before eating.Sprouts should smell fresh and clean. Anything sour, musty, slimy or discoloured goes in the bin — do not rinse it and hope.
7. For microgreens, sow thickly on damp compost.A shallow tray with drainage, filled with peat-free compost, firmed and dampened. Scatter seed densely across the surface, press it in, and cover very lightly or not at all.
8. Give microgreens light from the start.A bright windowsill. Unlike sprouts, these are grown in the light so they green up and develop flavour. Turn the tray daily so they do not all lean one way.
9. Water microgreens from below.Standing the tray briefly in shallow water keeps the leaves dry and reduces damping off in a dense stand.
10. Cut microgreens with scissors above the compost.At the seed leaf or first true leaf stage, usually one to three weeks. Cut above the surface so no compost or root comes with them. Most do not regrow — sow a fresh tray.

Tips

• Pea shoots from a bag of dried marrowfat peas from the supermarket are the cheapest fresh green you can produce indoors.
• Sunflower and pea shoots are substantial enough to be a salad in themselves; alfalfa and cress are garnishes.
• Sow a new microgreen tray every week and you have a continuous supply from a windowsill through the darkest months.
• Damping off is the main microgreen failure — too dense, too wet, no airflow. Water from below and give the tray some air.
• Cooking sprouts — a quick stir-fry or in a soup — removes the food safety concern entirely while keeping most of the texture.

Common mistakes

• Sprouting garden seed sold for the vegetable plot — It may be treated with fungicide and is not produced to the standards used for seed intended to be eaten whole.
• Leaving the sprouting jar standing in water — Stagnant water at the bottom is where bacteria multiply. The jar must drain freely between rinses.
• Skipping rinses for a day — Twice daily is the standard for a reason. A jar left unrinsed in a warm kitchen is not safe to eat from.
• Growing microgreens in the dark like sprouts — They come up pale, leggy and flavourless. Microgreens want light from the moment they emerge.

Alternatives

• Jar sprouting: Cheapest and fastest — three to five days, no compost, no light needed. Requires disciplined twice-daily rinsing and carries the food safety considerations described above.
• Microgreens on compost: One to three weeks, needs a tray, compost and a bright windowsill. Better flavour and texture, and no sprouting hygiene risk because you cut above the soil.
• Pea shoots: The best-value indoor crop — ordinary dried marrowfat peas sown thickly on compost, cut at about 10cm, and they often give a second cut.
• Windowsill herbs and salad: A slower but longer-lasting alternative — a pot of cut-and-come-again salad on a bright sill produces for weeks rather than days.

Questions people ask