MIXC 10-Pack 7-Inch Vented Humidity Domes for 10 x 20 Trays: specs

A humidity dome is a clear plastic lid that sits over a seed tray and holds in moisture and warmth while seeds germinate or cuttings root. MIXC makes a 7-inch-tall version with four adjustable vents, sold in a pack of ten, designed for standard 10 x 20-inch flat trays.

What a humidity dome does

Seeds and fresh cuttings generally need steady moisture and a stable temperature. An open tray loses water to the air quickly, so a dome slows that loss. Once the seedlings emerge, the vents are opened to let air circulate. This helps avoid the stale, constantly wet conditions that can invite mould, and it gets young plants used to normal air.

Four vents instead of two

MIXC says most domes have two vents and that its dome has four adjustable ones. More vents give finer control: you can open one or two on a mild day and all four when the dome is getting too humid or warm. The vents are adjustable rather than fixed holes, so you can change the setting as seedlings develop.

Size and fit

The dome measures 21.25 x 11.02 x 6.77 inches (about 54 x 28 x 17 cm). MIXC says it sits securely on its own heavy-duty 1020 flat trays and on other standard 10 x 20-inch trays, and describes a snug fit and a tight seal for retaining warmth and humidity. At about 6.8 inches, the dome gives seedlings headroom before it has to come off, though taller plants will need it removed sooner or later.

Material and weight

MIXC describes the dome as durable and lightweight, and the whole ten-pack is listed at about 4.7 pounds (2.1 kg). Lightweight lids are easy to lift and stack, and a clear plastic of this kind can usually be washed and reused season after season. Wash trays and lids between batches to cut down on disease carry-over.

Typical uses

• Starting vegetable, herb and flower seeds indoors before the outdoor season.
• Rooting cuttings, which MIXC lists as seed, clone and cutting propagation.
• Giving a protected spot to delicate seedlings in a cool room.

Using one well

1. Fill the tray or cell inserts with a seed-starting mix and sow.
2. Water gently and put the dome on with vents mostly closed.
3. Keep the tray where it gets suitable light and warmth for the species.
4. Open vents as soon as seedlings appear, and remove the dome when plants touch the lid.

What to check before you buy

• Tray size: the dome is for 10 x 20-inch trays. Measure yours, including the rim, before buying.
• Height: 7 inches suits seedlings and cuttings, but check it against what you plan to start.
• Quantity: ten domes need ten trays, or enough space to run several batches.
• Light and warmth: a dome only holds in conditions; it doesn't provide them.
• Storage: nested domes take less space, though ten still need a shelf.
• Cleaning: plan to wash them between uses.

The short version

• Ten clear domes, each 21.25 x 11.02 x 6.77 inches.
• Four adjustable vents for humidity control.
• Made to fit 1020 flat trays and other standard 10 x 20-inch trays.
• Aimed at seed starting, germination and cutting propagation.

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