With the Grodan 6" Gro-Block Hugo with Holes, you can grow cuttings and grow plants to maturity in premium stonewool. Grodan invented stonewool in the Sixties as a more environmentally-sustainable and resource-efficient growing medium alternative. Grodan stonewool is top-quality stonewool and can be used in both hydroponics and soil systems. The Hugo Gro-Block is a 6" by 6" by 6" cube. The 1.5" diameter hole in the Grodan Hugo Gro-Block works great with A-OK starter plugs and macroplugs.