Soil vs. Hemp Mat vs. Paper Towel: The Best Growing Medium for Microgreens

Microgreens in ten days covers the soil method start to finish, but soil isn’t the only thing you can grow a tray on — and it isn’t always the right choice. Reusable mats and plain paper towel both show up constantly in microgreen forums and videos, and each solves a different problem soil has. Here’s how the three actually compare, so you can pick by what you’re optimizing for rather than by whatever the last video you watched happened to use.

The three options at a glance

Medium	Reusable	Cleanup	Moisture control	Best for	Where to buy
Potting soil / compost	–No	Messiest — soil clings to roots and stems	Forgiving; holds water evenly	Biggest, sturdiest yields; growing past microgreen stage	—
Hemp or coco coir mat Best all-round	✓Yes	Low — lift the whole mat out, rinse or compost it	Good; holds moisture more evenly than paper	A repeatable weekly routine with less cleanup than soil	Search on Amazon (affiliate link, opens in a new tab)
Paper towel	–No	Low, but dries out and needs frequent misting	Poor; dries fast, needs checking 2–3x a day	Testing germination rate on new seed; a first tray with zero setup	—

'Reusable' means the medium itself can be used for more than one grow, not that a single mat lasts forever — a hemp or coco coir mat typically holds up for a handful of cycles before it breaks down. Cost figures for each option are covered separately below as typical market ranges, not a specific listing's price.

Potting soil or seed-starting compost

Soil is what the ten-day method uses, and it’s still the right default for most people. It holds water evenly without you having to check it constantly, it’s the cheapest medium per tray by a wide margin if you already garden, and it produces the biggest, sturdiest microgreens of the three — the growing medium actually feeds the roots here, rather than just holding moisture against them.

The tradeoff is cleanup. Every harvest leaves you with a tray of spent compost and a colander of greens with soil worked into the base of the stems, which means a rinse before anything reaches the cutting board. Soil also isn’t reusable tray to tray — each grow starts with a fresh 3cm layer.

Hemp and coco coir grow mats

A grow mat is a thin, pre-cut pad of pressed hemp or coconut coir fibre, sized to fit a standard tray. You sow directly onto the mat instead of onto soil — the seed roots grip the fibre instead of compost.

The main appeal is cleanup: lift the whole mat out after harvest instead of scraping soil out of a tray. Hemp mats are typically sold as biodegradable and can go straight into a compost bin once they’re too matted with roots to reuse, which is usually after a handful of grows rather than indefinitely. Moisture control sits between soil and paper towel — mats hold water more evenly than paper, but dry out faster than a few centimetres of compost, so they still need checking daily rather than the “mist once and forget it” pattern soil allows.

Yield sits close to soil for most crops, since the mat itself has no nutrients — it’s purely a physical support, so the seed’s own stored energy does the work either way, the same as it does in the blackout period of the soil method.

Paper towel

The zero-setup option: fold a few layers of paper towel into a container, soak it, and sow directly on top. No trip to buy anything if you already have seed on hand.

The catch is moisture. A folded paper towel holds far less water than a mat or a few centimetres of soil, and it dries out fast under a grow light or a warm windowsill — expect to check it two or three times a day during germination, versus once for soil. Skip a check and the tray can dry out and stall, or oversaturate into the kind of standing water that invites the mould problem covered in the troubleshooting section of the ten-day guide. Paper towel also isn’t reusable — it’s spent after one grow, same as soil, just without soil’s nutrient contribution.

Typical cost, roughly

Soil is usually the cheapest per grow if you already have a bag of potting mix or compost on hand — a bag that costs a few dollars covers many trays. Hemp and coco coir mats are typically sold in multi-packs of 10 for a common tray size, working out to somewhere in the range of a dollar or two per mat, though hemp generally costs a bit more than coco coir. Paper towel is close to free if you already buy it for the kitchen, but factor in that a dried-out tray from under-misting is a wasted sowing — the cheapest medium isn’t the cheapest choice if it fails more often.

Which one should you use

First tray, or testing old seed: paper towel. Nothing to buy, and you’ll know within days whether the seed is worth committing to.

A weekly rotation you plan to keep up: a hemp or coco coir mat. Less mess than soil, more forgiving on moisture than paper towel, and it’s the medium that best matches running two trays a week apart without cleanup eating into the time savings.

Big, sturdy shoots, or anything you might let grow past the microgreen stage: soil. It’s still the only one of the three with real nutrient reserve behind it.

None of the three is wrong — they trade cleanup, moisture forgiveness and cost against each other differently, and plenty of people who grow microgreens regularly end up using more than one depending on the crop and how much attention that week has to spare.