Grodan Rockwool / Stonewool 4 Inch Gro Blocks (Unwrapped) – Case of 144


SAVE $10.22 (5%)

Made in Denmark since 1969, Grodan rockwool (also called stonewool) is widely recognized as the ideal soilless substrate. For any growing application, rockwool offers speed, ease of use, and cleanliness. Rockwool is an alternative to coco coir and expanded clay for hydroponic applications.

  • 4" Gro Blocks can be used as an intermediary or final container for planting.
  • Grodan A-OK Staters and Macroplugs fit snugly into the pre-formed hole on the top of the 4" Gro Block.
  • NOTE: Product may differ from image, cubes come unwrapped
  • Comes in a commercial case of 144 blocks

More Info

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Grodan Rockwool / Stonewool 4 Inch Gro Blocks

Grodan partnered with the Wageningen University and Research Facility and top growers to determine the optimal stone wool substrate and irrigation strategies for indoor and greenhouse specialty crops. The result of this scientific rigor is Grodan Improved with our Advanced Wetting Agent. These leading-edge blocks and slabs have the optimal fiber structure and physical properties for crop uniformity, more even Water Content (WC) and Electrical Conductivity (EC) distribution throughout the entire substrate, and the greatest steering capabilities available. These benefits translate to higher yields, improved quality, less water and nutrient usage, and reduced sensitivity of the crop to diseases.

Excellent control

The improved initial saturation and improved water distribution throughout the height of the blocks results in improved root growth, enhanced water holding capabilities, and more stable EC behavior in the root zone. This makes it is easier than ever before to control your crop, with even less inputs, from propagation through to harvest.

Greater steering possibilities

The advanced technology used in Grodan Gro-Blocks Improved combined with the uniformity of WC and EC throughout the entire block providing better vegetative and generative steering. WC and EC can be adjusted more rapidly and efficiently.

Roots making better use of the entire substrate volume

Both the rooting-in and rooting-through plant processes in Grodan Improved occur several days faster, speeding up the vegetative phase and time to harvest. The more effective rooting-through of the entire substrate volume leads to a visible increase of roots and thus, better water and nutrient uptake.

Dimensions (WxHxL)

4″ x 4″ x 4″

Commercial Case: 144 Gro-Block


Weight 26 lbs
Dimensions 16.5 × 24.5 × 24.25 in

Product Category

Soil & Grow Mediums


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