12-Cell Seed Starter Tray with Vented Dome

$19.99

Color Black Green

Quantity

A 12-cell tray with a clear dome and a vent you can open by hand.

The plain version of a seed tray, and for a lot of sowing it is all you need. Twelve cells, each with a drainage hole, sitting in a solid base tray so you can water from below.

The dome is the useful part. It keeps the compost surface from drying out while seeds germinate, and the cap on top twists open so you can let air in the moment seedlings appear.

One tray is a small commitment — a batch of herbs, a few tomatoes, a row of salad — and they stack for storage.

Fill the cells with damp seed compost and level it off.
Sow one or two seeds per cell at the depth on the packet.
Fit the dome with the vent closed and put the tray somewhere warm and bright.
Twist the vent open as soon as the first seedlings show.
Water by adding to the outer tray and letting the cells draw it up.
Take the dome off once the seedlings touch it, and pot on at the first true leaves. Squeeze the base of a cell to pop the plug out cleanly.

Cells: 12, each with a drainage hole
Footprint: about 7.3 x 5.7 in
Parts: clear dome with twist vent, 12-cell insert, solid base tray
Colours: green or black
Material: plastic, reusable

Compost and seeds are not included, and there is no light or heat mat in the box.

Colour only, and it is purely cosmetic: green or black, both the same tray under the same clear dome. The black one hides algae on the base better.

No light and no heat mat included — this is the tray on its own.
Open the vent once seedlings are up. A shut dome over damp compost invites mould.
The supplier says it tolerates use on a heat mat below about 120°F. We would keep any mat on its lowest useful setting regardless.
The cells are deliberately flexible so plugs pop out. That also means the tray is easy to crack if you lift it by one corner when full.

Does it come with a light?

No. This is the tray, insert and dome only. Our other seed-starting kits include LEDs if that is what you need.

Do the cells drain?

Yes, one hole per cell, over a solid outer tray, so you can water from underneath.

Can I put it on a heat mat?

The supplier says yes, up to about 120°F. That is their figure rather than a tested one, so keep the mat modest.

How big is it?

About 7.3 x 5.7 in, so it fits a standard windowsill.

Why you'll love it

A vent you can actually adjust. Twist it open the day seedlings appear.

Waters from below. Drainage holes over a solid base tray.

Windowsill sized. About 7.3 x 5.7 in, and they stack away flat.

One seed per cell, or two?

Sow two. Not every seed comes up, and an empty cell in a twelve-cell tray is a real loss when you are only sowing one tray.

The part people find uncomfortable comes next. If both germinate, you keep the stronger one and remove the other — snipped off at compost level rather than pulled, so you do not disturb the roots of the one that is staying. Two seedlings sharing a cell this size will compete, and you end up with two weak plants instead of one good one.

Old seed is the exception worth noting. If a packet is a few years past its date, sow three or four and expect to thin more.

A quick guide for your growing space

Warmth

Seeds germinate within a temperature range rather than at one magic number, and a cold windowsill in February is often the whole reason nothing comes up. Somewhere that stays at normal room temperature is usually enough.

Humidity

A clear dome holds moisture around seedlings while they root, but still, damp air is also how mould gets started. Open the vent once the seedlings are up, and let the surface dry a little between waterings.

Short days

Winter is when a grow light earns its keep. Put it on a timer and give a consistent day length rather than leaving it on around the clock, because plants use the dark hours too.

Small spaces

Growing indoors is mostly a question of surface. A tray on a shelf, a light clipped over one pot, or a tower that stacks upward all trade floor space for height.