Made in Denmark since 1969, horticultural stonewool is used the world over by both hydroponics and soil gardeners. Growers can start cuttings and even grow plants to maturity in this large Grodan Gro-Block or transfer it to a larger stonewool slab once roots have been established. Gro-Blocks can be planted directly into containers for soil gardening as well. This is a single 6" x 6" x 6" Gro-Block with a preformed hole. Grodan stonewool is known for its quality, consistency and performance.