Grodan Multiblocks are designed for seed and cutting propagation prior to "blocking on" into the larger growing blocks. Multiblocks are a free standing module-type growing system. The V-shaped individual "cells" within a multiblock sheet allow effective air pruning. This encourages rooting within, rather than between, individual blocks. All multiblocks come in 1.5" blocks and fit in a standard 10x20 propagation flat.