A-OK cubes are extremely popular options for propagation, for lettuce, herb and leafy green production in NFT gutter systems, and as the first step in slab and block production (Hugo blocks). A-OKs are suitable for sowing and sticking. Choose 1.5" A-OKs when moving up to Delta or Hugo blocks. 1" cubes are popular options for lettuce and herb production. A full sheet of A-OK cubes will fit in a standard 10 x 20 tray.