How to grow microgreens without soil (hydroponic)

You do not need soil to grow microgreens. As a quick answer: sow the seeds on a moist soil-free pad — hemp, felt, jute, coconut coir, or even paper towel — in a shallow tray, keep the pad evenly moist, and harvest in one to two weeks. Because microgreens are cut so young, the seed carries almost all the energy they need, so plain water on a pad is usually enough. This is a tidier, indoor-friendly take on the full microgreens method.

Why grow microgreens without soil

The soil-free method trades a little yield for a lot of convenience:

• No mess. No bags of potting mix, no soil to spill on the counter.
• Clean harvest. Cutting above a pad gives grit-free greens with no soil to rinse out.
• Easy reset. Lift the spent mat, compost it, and start again.

It is the method most people mean by “hydroponic microgreens,” and it borrows the same principle as passive hydroponics — the growing medium wicks water to the roots. If you are curious how passive water culture works more broadly, see the Kratky method for beginners.

How to do it

1. Wet the pad. Lay a hemp or felt mat (or a few layers of paper towel) in a shallow tray and moisten it thoroughly, pouring off any standing water.
2. Sow densely. Scatter seeds across the pad, as thickly as for the soil method. Large seeds like peas and sunflower do better soaked first.
3. Cover to germinate. Keep the tray dark and humid for the first few days until the seeds sprout.
4. Uncover under light and keep the pad moist — add water to the tray base so it wicks up, rather than soaking the greens from above.
5. Harvest at the first true leaves, cutting just above the pad.

Do they need nutrients?

For most crops, no. Microgreens are harvested before they exhaust the seed’s reserves, so a pad kept moist with plain water grows a full tray. For slower or larger varieties you can use a very dilute nutrient solution, but it is optional — keep it weak, the same low-EC principle used for leafy crops elsewhere on the site.

Getting the moisture right

The one thing to watch is water. A pad that dries out stalls germination; a pad that sits flooded goes slimy and moldy. Aim for evenly damp, never waterlogged, water from below, and keep airflow in the room. That single habit is the difference between a clean tray and a moldy one — the same rule that governs the soil method in how to grow microgreens at home.

Which seeds to start with

The soil-free method suits the same forgiving varieties as any beginner tray — radish, broccoli, mustard, peas, and sunflower. See best microgreens for beginners to choose, and skip gel-forming seeds like chia and cress until you are comfortable, since they hold surface moisture and can mold on a pad.