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Grodan Rockwool SBS Cubes are the inert, sterile substrate for hydroponic propagation. Uniform density guarantees optimal air/water balance and rapid root growth for consistent seedlings and cuttings. Essential pre-soaking required.
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Achieve professional-grade results from the very first step with the Grodan SBS (Single Block System) Rockwool Cube Tray. As the global market leader in stone wool growing media, Grodan offers an unparalleled, inert substrate perfect for seed germination and establishing cuttings. The SBS tray simplifies handling and features a unique, uniform, high-density structure, ensuring the optimum air-to-water ratio for rapid root growth and consistent development across every plant. Choose the 150-cube tray for high-volume starts or the 77-cube tray for larger-scale initial propagation.
Key Benefits of Grodan SBS Cubes
- Optimal Air/Water Balance: The proprietary rockwool structure is engineered to hold ample nutrient solution while retaining over 18% oxygen, creating the perfect, well-aerated root environment essential for fast, healthy starts.
- Hygienic and Pathogen-Free: Manufactured by melting basalt rock at extreme temperatures, the stone wool is a clean, inert growing medium that is sterilised and free from pathogens, pests, and weed seeds, drastically reducing risk.
- Uniformity and Consistency: Features a homogenous density and fibrous structure, guaranteeing uniform distribution of moisture, nutrients, and stable pH, leading to consistent, predictable growth across all your seedlings and cuttings.
- Easy Transplanting: Supplied in a convenient plastic tray for simple handling, the single block system allows for seamless transplanting of the well-rooted cube directly into larger Grodan Delta Cubes, Grodan Slabs, or other growing media.
- Precision Control: As an inert substrate with minimal Cation Exchange Capacity (CEC), it gives the grower complete control over the nutrient and water content, making it the ideal choice for controlled, automated hydroponic systems.
How to Use Grodan SBS Rockwool Cubes
Preparation (Crucial Step): Rockwool has a high, alkaline pH straight from the packet and must be neutralised before use.
- Pre-soak the entire tray of cubes for a minimum of 6 hours, or ideally 24 hours, in a water solution adjusted to a pH of 5.5 to 5.8. Use a dedicated pH Down solution and a pH testing meter for accuracy.
- Gently shake off excess water—do not squeeze the cubes, as this will damage the structure and compromise the essential air pockets.
Propagation:
- For Cuttings: Dip the base of your prepared cutting into a quality rooting gel like Clonex Rooting Gel or liquid stimulator. Insert the cutting into the pre-drilled hole in the cube.
- For Seeds: Place one or two seeds into the hole and lightly pinch the stone wool closed over them.
- Place the trays into a propagator or under a humidity dome to maintain high humidity (70–80%).
- Once the first roots emerge from the sides or bottom of the cube, your young plant is ready for transplanting into a larger Grodan Block or your main system.
For a more in-depth guide on how to take cuttings check out our blog post: The Art of Propagation: How to Take Cuttings Like a Hydroponics Pro.
Available Sizes:
- 1" / 25mm x 150 Small Cubes with Hole
Small starter cubes for growing from seeds and cuttings that fit into the small hole cubes
- 150 cubes per tray - 1.5" / 36mm x 77 Large Cubes with Hole
Large starter cubes for growing from seeds and cuttings that fit into the large hole cubes
- 77 cubes per tray
Frequently Asked Questions
Why do I have to pre-soak Grodan Rockwool cubes?
Rockwool is manufactured using molten basalt rock, which results in a naturally alkaline medium (high pH). Pre-soaking in a pH-adjusted solution (typically 5.5-5.8) is essential to neutralise the medium and prevent nutrient lockout, ensuring your seedlings and cuttings can absorb necessary elements.Do I need to wear protective gear when handling the cubes?
Yes. Although Grodan is clean, stone wool consists of fine mineral fibres. It is highly recommended to wear gloves and a dust mask when handling large quantities or cutting rockwool blocks to avoid skin irritation and inhaling dust.When is the best time to transplant the plant from the SBS cube?
Transplanting should occur as soon as the first healthy white roots are visibly emerging from the bottom or sides of the SBS cube. At this stage, the root system is robust enough to colonise the larger medium, such as a Grodan Delta Block, without suffering shock.Can Grodan Rockwool be reused for a new crop?
Yes, Grodan rockwool is durable and can be reused. It must first be thoroughly cleaned and chemically sterilised (often with diluted hydrogen peroxide or bleach) to eliminate any lingering pathogens or algae from the previous cycle, before being re-soaked in a fresh, pH-adjusted solution.SKU: 1064 Free delivery on orders over £60*
- UK Mainland onlyStandard Delivery £4.95
- Heavy / Large item surcharge £2 per item
- 1-3 Days**
- UK Mainland onlyExpress Delivery £8.95*
- Next Working Day**
- UK Mainland onlyScottish Highlands £15.95*
- 2-5 Days***Can not be used with Heavy / Large items
**If ordered on a working day before 2pm cut off (Saturday and Sunday are not classed as working days).Please See Delivery and Returns page for more details.
