Grodan Gro Block Improved GR10 Large 4" w/Hole 4" x 4" x 4" Shrink-wrapped/Strip

Grodan partnered with Wageningen University and Research in the Netherlands, and leading growers across North America, to identify optimal rockwool substrate and irrigation strategies for specialty crops. Months of scientific research and trials resulted in Grodan Gro-Blocks Improved with Grodan's Advanced Wetting Agent.

These state-of-the-art blocks feature the optimal fiber structure and physical properties for crop uniformity, more even water content (WC) and electrical conductivity (EC) distribution throughout the block, and the greatest steerability available. Water distribution is more uniform throughout the block, which is the foundation for a well-defined root system with greater water and nutrient absorption capacity, producing robust and vigorous crops.

The new and improved wetting agent, coupled with hydrophilic technology, significantly enhances the water characteristics of Grodan Gro-Blocks Improved, achieving even more uniform water distribution along the height of the block. This results in greater plant development, better steerability, and more efficient use of water and nutrients.

The optimized wool structure allows for faster rooting and quicker replenishment of the nutrient solution, while the Gro-Block Improved maintains its structure, firmness, and rigidity throughout the cultivation process.

Available in 6-unit strips.

Technical Data

• Dimensions: 4 in x 4 in x 4 in | Model: GR10 Large with pre-cut hole
• Shrink-wrapped packaging that maintains sterility until use
• Improved Grodan rockwool — balanced water retention and high air content
• The pre-cut planting hole accommodates propagation plugs for seamless transplanting
• Compatible with drip irrigation systems and Grodan slab transplanting programs

How to use

• Pre-soak in pH-adjusted water (5.5–6.0) for 1 hour until fully saturated
• Insert the plug with the seedling into the central hole at the time of transplanting
• Install drip irrigation directly over the block — water frequently in small doses
• Monitor drainage EC to adjust nutrient solution concentration over time
• Do not reuse blocks between cycles — recycle them through a certified rockwool program