Grodan Gro-Block Improved GR22, Jumbo, 6 x 6 x 4, Case of 64 Advanced Nutrients so airflow holds up through

so airflow holds up through carbon filters and long duct runs

whether at the bottom of the pot as additional drainage or as part of the mix

the bag has easy carry grip handles

no banned plant growth regulators are used

New Sizes added for larger grows that prefer pre-mix liquid nutrients

Grodan Gro-Block Improved GR22, Jumbo, 6 x 6 x 4, Case of 64 Advanced Nutrients so airflow holds up throughGrodan Improved Jumbo (White Foil) 6 x 6 x 4 (Case of 64) Keep it Real Real Science Grodan partnered with the Wageningen University and Research facility in The Netherlands and top growers throughout North America to identify the optimal stone wool substrate and irrigation strategies for specialty crops. The result of months of scientific research and trials is Grodan Gro Blocks Improved with our Advanced Wetting Agent. Real Improvement These leading