Grodan 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 in making different types of fibers. The purpose is to support the requirement of the plant in the different plant stages. Grodan has a tremendous capacity for absorbing nutrient solutions while retaining plenty of oxygen for rapid plant growth. Grodan Delta features improved grooves at the base to promote better drainage. These growing blocks are used for direct sowing or "blocking on" of macro and multiblock raised plants. AO 36/40 plugs fit well into the hole sizes provided by the blocks.

• Includes: 6 Pack of Grodan 4" Delta 10 + Twin Canaries Chart
• Has a tremendous capacity for absorbing nutrient solutions while retaining plenty of oxygen for rapid plant growth
• Even， rapid water distribution throughout the media
• Very controllable， so growers are able to steer plant growth
• Usable in recirculating systems from first drain， reducing water and fertilizer usage
• Uniform growing substrate which results in consistent plant growth
• Inert， meaning it will not add or hold back any nutrients or water from the plant
• Lightweight， pathogen-free， disease-free， seed-free
• Excellent buffer and re-saturation capability