Ready Gro Super Plugs are the perfect biodynamic plug for seedlings or cuttings. Also designed for convenience, you can easily transplant plugs into soil or soilless hydroponic applications. The 1.5 x 1.5 size also fits perfectly into rockwool holes. Super Plugs are made of composted tree bark and organic materials giving them a sponge like structure. These premium plugs are made through an advanced proprietary composting method and contain natural beneficial fungi from this advanced composting biotechnology. Ready Gro Super plugs are biodegradable and 100% organic. Shipped in a poly bag inside a cardboard carton.