Jiffy Seed Starting Greenhouse - 25-Cell, 42mm Pellets

42mm Peat Pellet Seed Starting Kit with Bonus SUPERthrive, 25-Cell

Starting seeds indoors means giving them a stable microclimate until they're big enough for the garden, and piecing that together from a separate tray, pots, and a humidity cover is where a lot of first-time indoor growers stall out. Jiffy's 42mm pellet greenhouse kits put a watertight tray, a fitted humidity dome, and pre-measured peat pellets into one box, so seed starting begins with unboxing rather than shopping for parts.

The 25-cell size fits a fuller flat of herb, flower, or vegetable seedlings and includes a bonus SUPERthrive sample, so growers starting several varieties at once have room and a head start on root development.

Key Features & Benefits

• 42mm biodegradable peat pellets — compressed peat that expands with water into a self-contained growing cell.
• Watertight base tray — holds the expanded pellets and lets you bottom-water without spilling.
• Clear humidity dome — traps warmth and moisture over the pellets until seeds germinate.
• Direct-transplant pellet netting — the whole pellet goes into the garden with the seedling, no root disturbance.

Who Should Use This

This kit fits home gardeners and hobbyist growers starting herbs, flowers, and vegetable seedlings indoors on a windowsill or under lights before the outdoor planting season begins.

About Jiffy

Jiffy is the seed-starting division of Green Garden Products, a company with roots in the Jiffypot, the original biodegradable peat pot designed for direct-to-garden transplanting. That direct-transplant thinking carries through Jiffy's whole product line, from individual pots to the pelletized kits here.

Frequently Asked Questions

How do I use this greenhouse kit

Set the peat pellets into the tray, add warm water, and let them fully expand before sowing seeds into the top of each pellet. Replace the humidity dome until seedlings emerge, then remove it gradually to let them acclimate to open air.

When should I remove the humidity dome

Take the dome off as soon as the first seedlings emerge, or crack it open for a day or two if only some cells have sprouted. Leaving the dome on too long after germination can encourage damping-off and other moisture-related seedling problems.

Can I transplant the pellet directly into soil

Yes, the biodegradable netting breaks down in moist soil, so the whole expanded pellet goes into the ground with the seedling and roots keep growing without disturbance. This is the same direct-transplant approach used across Jiffy's peat pellet and peat pot products.

What's the difference between the 10-cell, 25-cell, and 50-cell kits

The kits use the same tray-and-dome design and 42mm pellet size, just scaled to different cell counts, so the choice comes down to how many seedlings you're starting at once. The 25- and 50-cell kits also include a bonus SUPERthrive sample, with the 50-cell kit adding plant markers as well.