Most sowing advice assumes a seed you can see. Radish, pea, sunflower — big, round, easy to spread by hand and easy to correct if you go heavy in one corner.

Amaranth, sorrel, basil, watercress and celery are a different job. The seed is close to dust, static makes it cling to your fingers, and a moment of clumsiness puts a third of the tray in one spot. The result is a mat that is dense in some places and bare in others, and neither part grows well: the dense patch traps moisture and goes mouldy, the bare patch never fills.

This is a handling problem, not a quantity problem. Our seed density guide tells you how many grams to use; this is about getting those grams to land where you want them.

1. Use a shaker

The simplest fix, and the one most growers land on eventually: a spice or salt shaker. Fill it, then move it steadily across the tray in overlapping passes, the way you would season a steak rather than the way you would pour cereal.

It is a common enough trick that growing manuals recommend it outright — Nicolas Plant's Microgreens Growing is blunt about needing one rather than trusting your hands. The reason it works is that a shaker meters the seed for you: the hole size decides the rate, so your hand only has to control position.

Check the hole size against your seed before you commit a whole packet. Too large and it pours; too small and it clogs.

2. Dilute it with a carrier

If you cannot get an even spread because there is simply not much seed to spread, add bulk that does not grow. Dry sand, or fine dry vermiculite, mixed with the seed at roughly four parts carrier to one part seed, turns a teaspoon of dust into something you can distribute deliberately.

Mix thoroughly and use it immediately — the two will separate if it sits, and then you are back where you started with the seed concentrated at the bottom.

3. Sow in two passes, at right angles

Halve your seed. Sow the first half moving north-to-south across the tray, the second half east-to-west.

This is the single highest-value habit on this list and it costs nothing. A single pass carries your unevenness in one direction; the crossing pass fills exactly the gaps the first one left. It works with a shaker, with a carrier, and with bare hands.

4. Mist, do not pour

Tiny seed floats. A stream of water from a jug will move a carefully sown surface into rafts and bare patches in about a second, undoing all of the above.

Mist from a spray bottle until the surface is damp, and water from below afterwards if your setup allows it. This matters more for fine seed than for anything else you grow.

What good looks like

Seeds should sit close but not touching, in a single layer, with no visible clumps and no patches of bare substrate wider than a fingernail. Look across the tray at a low angle rather than down at it — clumping is much easier to see in profile, and you can still nudge it with a dry fingertip before the water goes on.

Fine seed also tends to belong to the slower crops, which means longer under cover and more time for a problem to become a mould problem. Getting the sowing right is the cheapest insurance available; the blackout method covers what happens next, and sorrel is the crop where all of this matters most.

The shaker technique in this article is drawn from Microgreens Growing: Step by Step by Nicolas Plant.