Jiffy Gro-Dome Plant Tray Cover — 11" × 22" Clear Humidity Dome for Seed-Starting (Model TDOME)

The Jiffy Gro-Dome Plant Tray Cover is a clear plastic humidity dome sized to fit a standard 11" × 22" (1020) seed-starting tray. Drop it over your tray of seedlings or peat pellets to lock in moisture and warmth during the critical germination window — the mini-greenhouse effect that turns dry seed starting into reliable, even germination.

What It Does

• Maintains greenhouse humidity — traps moisture from your watered tray to keep seeds and surface-sown starts from drying out between waterings
• Holds heat — warms the air space above the soil, speeding germination of warm-season crops (tomatoes, peppers, eggplant, basil)
• Clear plastic — lets full light reach seedlings as they emerge so they don't stretch and get leggy looking for a window
• Reusable — one dome lasts many seasons; rinse between uses and store dry
• Recyclable plastic — made in the USA from recyclable material

Where It Fits

• Standard 11" × 22" (1020) seed-starting trays — the industry-standard size used by nearly every nursery and seed-starting kit
• Jiffy peat-pellet trays, plug trays, and seedling six-packs
• Windowsill, heat-mat, or grow-light setups
• Cuttings and propagation flats where humidity is essential

How to Use

1. Sow your seeds in a 1020 tray, peat pellets, or plug tray. Water until soil/peat is evenly moist (not soaking).
2. Place the dome over the tray. The lip seats around the tray edges for a snug fit.
3. Set on a warm spot — on a heat mat for warm-season crops, or just a warm room for cool-season starts.
4. Check daily for condensation on the dome interior — that's the system working. Lift briefly to vent and refresh air every day or two so mold doesn't establish.
5. Remove the dome as soon as seedlings emerge and start touching the underside — from that point they need airflow to develop strong stems and avoid damping-off. Don't wait for true leaves; the dome comes off at first cotyledons.
6. Clean & store — rinse with warm water (mild bleach solution if you had a damping-off problem); air dry; nest with other domes or trays for storage.

What This Is — And What It Isn't

The dome only. Tray, soil, seeds, heat mat, and grow light are sold separately. The dome is the clear plastic cover designed to seat over a standard 11" × 22" tray.

For seedling germination, not long-term growing. Once seedlings emerge, remove the dome and transition to open-air growing under light. Domes left on too long cause weak, stretched stems and invite damping-off fungus.

Specifications

• Manufacturer: Jiffy (Jiffy Products / Plantation Products)
• Model: TDOME (also branded as “Gro-Dome”)
• Dimensions: 11" × 22" footprint (standard 1020 tray size); ~2" tall dome height
• Material: clear recyclable plastic (PETE/PET)
• Color: clear (for full light transmission)
• Reusable: yes — rinse and store between seasons
• Country of origin: Made in the USA
• UPC: 033349412210

What’s in the Box

• One Jiffy Gro-Dome Plant Tray Cover (clear plastic dome only; 1020 tray sold separately)

Best Paired With

• Jiffy 1020 Seed-Starting Tray — the dome was made for this tray; sold separately at Garoppo’s
• Jiffy peat pellets or peat pots — classic seed-starting media
• Seedling heat mat — pairs with the dome for warm-season starts (tomatoes, peppers, eggplant, basil)
• T5 or LED grow light — place 2–4 inches above seedlings as soon as the dome comes off
• Plant labels & markers — for tracking varieties across a multi-cell tray

Stop by Garoppo’s to pick one up, or schedule local delivery within our service area. Stock up before spring seed-starting season — one dome per tray is the standard setup.