Gro-Slabs are for the second or third stage of a plant's life. Slabs are available in a variety of sizes and come with instructions on the wrapping.
These slabs come in clearly marked biodegradable UV resistant poly sleeves. The poly sleeves have several functions; comfort in handling preventing algae growth, preventing roots and diseases from moving easily from slab to slab, minimizing evaporation, enabling full saturation of the slabs before use and controlling/directing the water-run off from the slabs.