If you want to start plenty of healthy, well-branched seedlings with good root systems in a compact space, rely on Park's Seed-Starting Cell Inserts! This 72-unit insert gives every seedling its own separate space for development before transplanting into the garden. They are economical and reusable, and are relied upon by professional growers for premium-quality plants. Made of black poly-plastic, each cell offers good drainage and plenty of room to grow. Use them to germinate seeds, or transplant seedlings from seed flats into them to grow on before setting out into the garden. One 72-cell insert (which breaks into 12 6-cell packs) fits perfectly into our bottom tray, which acts as a water catcher and carrying unit. If you would prefer to grow even larger seedlings for transplant, these inserts are also available in 36-cell and 48-cell sizes, which also fit into the bottom trays. Plus, our sturdy, reusable humidity domes fit the trays perfectly to keep drafts, temperature changes, and contaminants to a minimum! Mix and match all you like for the best possible start for your garden! If you're just starting out and looking for complete sets instead of the individual components, we offer the trays, humidity domes, and inserts together in the 36-cell set, 48-cell set, and 72-cell set.