Delta 4 Block, 3x3x2.5 with hole

Grodan Stonewool (rockwool) is made from molten rock spun into cotton candy-like fibers and then compressed into cubes, blocks, or slabs. Where other rockwool brand manufacturers cut all sizes from one batch of wool, Grodan is unique by making different types of fibers.

• Delta 4 Block, 3"x3"x2.5" with hole
• 8 blocks per strip
• These growing blocks are used for direct sowing or "blocking on" of Macro and Multiblock raised plan
• The blocks can then be placed on top of a slab to provide for a larger growing volume