SUNPACK® SUNPAD™ Lite Seedling Heat Mat — 45 W — 20.75 in x 20.75 in

Square-Format Bottom-Heat Mat for Double-Tray Propagation Setups

The SUNPACK SUNPAD Lite Seedling Heat Mat (45W, 20.75in x 20.75in) warms the root zone 10-20 degrees F above ambient air temperature, creating the warm, stable conditions seeds and cuttings need to root reliably. Bottom heat speeds germination and rooting across the board, from a windowsill seed tray to a full greenhouse propagation bench.

Pair the mat with a SUNPACK Heat Mat Temperature Controller (item SPTEMP, sold separately) to dial in an exact root-zone temperature rather than relying on a fixed heat output, and add a humidity dome over the tray to manage moisture alongside temperature. The mat's double-layer waterproof construction is built to hold up to the regular splashing and overhead watering that come with seed-starting and cloning.

Key Features & Benefits

• 10-20°F root-zone boost — Raises growing medium temperature above ambient air temperature for faster, more uniform germination and rooting.
• Double-layer waterproof construction — Built to shrug off the regular splashing and overhead watering that come with seed-starting and cloning benches.
• SPTEMP controller compatible — Works with the SUNPACK Heat Mat Temperature Controller (SPTEMP, sold separately) for precise, dialed-in root-zone temperature.
• Works with humidity domes — Pairs with a propagation tray dome so a grower can manage temperature and humidity together.
• 45W format — Sized to warm a specific tray footprint efficiently without wasting electricity on unused mat area.

Who Should Use This

Backyard gardeners starting a few trays of seedlings and commercial propagators running benches of cuttings both rely on bottom heat for consistent germination. This mat scales that same warm, stable root zone down (or up) to the tray size on hand, without requiring a whole-room temperature change.

Sizing & Compatibility

This 45W mat measures 20.75in x 20.75in and is sized to sit under a standard seed tray or cutting flat of matching footprint. Confirm your tray dimensions against the mat before ordering, since an undersized mat will not evenly warm an oversized tray.

Frequently Asked Questions

How much warmer does this mat make the root zone?

The SUNPACK SUNPAD Lite mat raises growing medium temperature roughly 10-20 degrees F above the surrounding air temperature. That range covers most seed-starting and cloning needs without a separate controller, though pairing it with the SPTEMP controller lets a grower dial in an exact target temperature.

Does this mat come with a temperature controller?

No, the mat itself is sold without a controller and runs at a fixed output when plugged directly into an outlet. The SUNPACK Heat Mat Temperature Controller (SPTEMP) is sold separately and lets a grower set and hold a specific root-zone temperature.

Is this mat safe to use with regular watering?

Yes. The mat uses a double-layer waterproof construction designed for the splashing and overhead watering typical of seed-starting and cloning trays. Even so, avoid setting the mat directly in standing water.

When should I use a heat mat instead of just warming the room?

A heat mat is the more energy-efficient option when only the growing medium, not the whole room, needs to stay warm for germination or rooting. It also lets a grower keep an otherwise cool room at a comfortable temperature while still giving seedlings the warmer root zone they need.

What tray size does this mat fit?

Each SUNPACK SUNPAD Lite mat is sized to a specific footprint, from a compact 3in x 20in strip mat up to a full 20.75in x 48in bench mat. Match the mat dimensions to your tray or flat before ordering so the entire base gets even bottom heat.