Cultiwool Cubes

Cultiwool Cubes — Professional Rockwool Propagation Medium for Hydroponics

Best for: Growers who need reliable seed starting and propagation cubes that actually deliver consistent results

Cultiwool Cubes are professional-grade stonewool propagation medium manufactured in Europe to exacting standards. Made from natural basalt rock, melted, spun, and compressed into uniform cubes with pre-punched holes, they deliver the air-to-water balance hydroponic propagation demands. Whether you're rooting cuttings, starting seeds, or transitioning plants into larger systems, Cultiwool gives you a sterile, pH-stable, inert foundation that actually performs. No nasties, no guesswork, no surprises.

How it compares

Cultiwool sits in the premium professional tier of propagation media.

• Grodan is the market leader; Cultiwool delivers equivalent performance at a sensible price point
• Made from basalt rock (not slag), ensuring purity and consistency in every cube
• RHP certified — meets strict European horticultural standards for safety and quality
• Outperforms budget alternatives (coco, perlite, clay pebbles) in germination rates and rooting speed
• Reusable in closed-loop systems, saving water and reducing waste

This is engineered propagation media, not a budget substitute. You're paying for reliability and results.

Usage guidance

Cultiwool cubes work across different propagation setups:

Seed starting
Soak cubes in pH 5.5–5.8 water with an EC of at least 1.5 mS/cm for about 30 seconds. Let them drain. Insert seeds into the pre-punched hole, keep moisture consistent, and germination rates typically run 70% or higher — well above alternatives.

Cutting propagation
Soak as above. Insert rooted cuttings into the hole. The donut-ring design guides water evenly across the cube, reducing dry spots and promoting uniform root development. Ready for transition in 7–14 days depending on conditions.

Hydroponic transition
Once roots emerge, place cubes directly into larger Cultiwool blocks or into your main hydroponic system (NFT, ebb and flow, drip). The cube integrates seamlessly without transplant shock.

Air-to-water ratio
When hydrated, Cultiwool delivers exactly 80% water, 20% air. This ratio is engineered to balance moisture retention with oxygen availability — too much water drowns roots, too much air dries them out. Stonewool gets the ratio right.

Technical specifications

• Material: 100% natural basalt rock stonewool (RHP certified)
• Air-to-water ratio: 20% air, 80% water when hydrated
• pH stability: 5.5–6.5 (neutral, naturally buffered)
• Inert composition: No nutrients, no contaminants, no organic matter breakdown
• Available sizes: 1.5" × 1.5" × 1.5" (mini), 3" (75mm), 4" (100mm)
• Hole options: Small hole (25mm plugs) or large hole (36mm plugs)
• Packaging: Single packs, strips, trays, or bulk cases (up to 2,250 cubes per case)
• Origin: European manufacture, high-density fiber construction
• Reusable: Can be sterilised and re-used in closed-loop systems

Who this is for

• Hydroponic growers needing consistent, reliable propagation performance
• Commercial or semi-commercial operations where germination rates and timing matter
• Anyone stepping up from peat pellets or foam cubes to proper stonewool
• Growers running ebb-and-flow, NFT, drip, or flood systems at scale
• Seed companies, nurseries, or serious hobby growers maximising crop yields
• Water-conscious operations looking to recirculate nutrient solution

Our take

Cultiwool Cubes are professional-grade propagation media that does exactly what it should. Inert, sterile, properly engineered, and proven to deliver higher germination rates and rooting success than budget alternatives. If you're serious about propagation — whether you're running five plants or five hundred — this is the foundation worth building on.

Competitively priced against Grodan and superior to everything else in its class. Good time to buy while clearance stock lasts.