Grodan 40mm Rockwool Cubes, Pack of 6. Hydroponic Propagation Starter Plugs Australia

The Commercial-Standard 40mm Rockwool Cube for Hydroponic Seed Germination and Cloning

Grodan is the benchmark for stone wool propagation media in professional horticulture. The 40mm x 40mm cube is the most widely used starter plug format in commercial hydroponics and indoor grow rooms globally — sized to balance moisture retention, root expansion space, and oxygen availability at the critical early stage of plant development.

Sterile, inert, and pH stable once conditioned, Grodan rockwool cubes give seeds and cuttings a contamination-free environment where root initiation happens faster and more uniformly than in organic or loose media alternatives.

Why Grodan Rockwool Outperforms Other Propagation Media

• High Air-to-Water Ratio. Stone wool fibre structure maintains oxygen availability at the root zone even when fully saturated, preventing the anaerobic conditions that cause damping-off and cutting failure.
• Sterile Growing Medium. Manufactured from inert mineral fibre with no organic matter to harbour pathogens, fungal spores, or competing biology. Reduces contamination risk significantly in clean propagation environments.
• Consistent Moisture Retention. Holds water evenly throughout the cube without oversaturation, providing steady hydration to developing roots without the wet-dry cycling that stresses cuttings.
• Uniform Fibre Structure. Encourages even root distribution through the cube rather than circling or matting, producing a root ball that transplants cleanly into larger hydroponic systems.
• pH Stable Once Conditioned. Pre-soak in pH 5.5-5.8 solution before use to bring the cube into the optimal range for hydroponic nutrient uptake.
• Commercial Grower Standard. Used in greenhouse and hydroponic production systems worldwide. The 40mm format is the industry default for seedling and clone propagation before transplanting to larger slabs or systems.

Technical Specifications

• Dimensions: 40mm x 40mm
• Material: Rockwool (mineral stone fibre)
• Structure: High-porosity fibre matrix
• Sterility: Sterile growing medium
• Water Retention: High, with drainage balance
• Aeration: High oxygen root zone
• Origin: Netherlands (Grodan manufacturing)

How to Use Grodan 40mm Cubes

• Pre-soak cubes in pH 5.5-5.8 water for 30-60 minutes before use. For enhanced root development, add Dutch Fest Root Mass Enhancer to your pre-soak solution at the recommended rate. Do not squeeze — allow to drain naturally to maintain fibre structure.
• Seeds: Place one seed per cube at 5-10mm depth. Maintain 22-26°C and high humidity until germination.
• Cuttings: Apply Clonex Rooting Gel to the cut stem before inserting into the cube. Keep under high humidity until roots are visible at the cube base.
• Transplanting: Move to the next system when roots emerge from the base of the cube. Do not remove the cube — transplant it directly into the larger medium or system.

Frequently Bought Together

• Clonex Rooting Hormone Gel. Apply to cuttings before inserting into Grodan cubes. IBA gel plus rockwool is the most reliable propagation combination for hydroponic cloning.
• Dutch Fest Root Mass Enhancer. Add to your pre-soak solution to prime cubes with root-stimulating biology before cuttings are inserted.
  
• HOMEbox R80S Propagation Tent. Dedicated 80x60x70cm propagation environment for full climate control over temperature and humidity during germination and cloning.
  
  Product Details

• Type: Stone Wool Propagation Cube
• Dimensions: 40mm x 40mm
• Application: Seed germination, cutting propagation, hydroponic cloning
• Compatible Systems: Hydroponics, DWC, coco, greenhouse production
• Pre-Treatment: Pre-soak at pH 5.5-5.8 before use
• Vendor: Grodan