Whether starting your seeds and cuttings in A-OK STARTER PLUGS™, MACROPLUGS™ or MINI-BLOCKS™, it is a good idea to transplant into a 3” or 4” block.
You’ll know it’s time to transplant to the Grodan GRO-BLOCK™ when the roots coming out of the starter are about 1” long. Just place your MINI-BLOCK™ on top of the 3” or 4” block without the hole OR your MACROPLUG/A-OK STARTER PLUG™ into the 3” or 4” block with the hole and watch your plant flourish.
Grodan Rockwool is an excellent quality stonewool substrate with a very high water holding capacity. Rockwool is absolutely free of disease, salts, and weed seeds. It has no Cation Exchange Capacity (CEC) so growers can take advantage of a nutritional program specifically tailored to their choice of crop. Set your plants into the Rockwool blocks then place those on top of the slabs. The roots will grow through the block and the slabs.
Nutrient solution may be applied through a spray or drip-emitter either directly to the slab or through the growing blocks. Blocks are commonly used for germination of seed and rooting cuttings. The vertically-oriented fibers in the blocks promote good downward root growth.
1 x 3" Gro-Block WRAPPED, Case of 384 x 3" Gro-Blocks WRAPPED, Case of 384 x 3" Gro-Blocks UNWRAPPED