Grodan MM 40/40 box / AO SBS cubes

Reliable germination and rooting from a trusted stone wool

Grodan MM 40/40, AO and SBS Cubes are premium stone wool propagation media that give seeds and cuttings the ideal balance of air and water while they establish. Made from hydrophilic stone wool with a uniform density, they hold consistent moisture and oxygen for rapid, even rooting - and they're clean, sterile and easy to handle. Used across hydroponics, indoor growing and vertical farming for vegetables, herbs and ornamentals, MM blocks suit transplanting while AO and SBS plugs are built specifically for reliable seed germination and propagation.

Fixing uneven germination and weak early roots

Uneven germination and weak root systems delay establishment and cut into final yields. These cubes provide a stable, sterile medium with strong moisture retention and oxygen availability, so roots develop quickly and evenly with consistent water and nutrient distribution - reducing the risk of overwatering or dry spots and encouraging vigorous growth once transplanted.

Key Benefits

• Premium stone wool media purpose-built for propagation
• Fast, even root development from an excellent air-to-water ratio
• Uniform density for consistent moisture across the tray
• Compatible with NFT, DWC, drip, flood-and-drain and vertical farming
• Clean and sterile, easy to handle for reliable, repeatable propagation

How to Use

1. Soak the cubes in clean water adjusted to pH 5.5-5.8 for around 15-30 minutes.
2. Let excess water drain naturally - do not squeeze the cubes, as this damages the fibre structure.
3. Place seeds or cuttings into the pre-formed planting hole.
4. Keep evenly moist, avoiding waterlogging.
5. Once roots emerge from the sides and base, transplant into a larger Grodan block, slab or your chosen system.
6. Begin feeding a light nutrient solution once germination or rooting starts, increasing strength as plants develop.