GRODAN BOX 3″ CUBES (SMALL HOLE 25MM)

Description

GRODAN BOX 3″ CUBES (SMALL HOLE 25MM) is the professional-grade rockwool propagation cube trusted by commercial hydroponic producers and serious home growers worldwide. We have been supplying Grodan products to UK growers since 2017 because Grodan’s manufacturing consistency — uniform density, precise hole depth, and optimal water-to-air ratio — produces rooting results that generic rockwool cubes simply cannot match.

Why Grodan’s Small-Hole 25mm Specification Matters

The small hole (25mm) version of the 3-inch cube is designed for rooting cuttings taken from 5–10mm diameter stems — the typical size for most vegetative cuttings from tomatoes, peppers, cucumbers, and a wide range of ornamentals and fruiting crops. The 25mm hole depth leaves a protective rockwool base below the cutting, ensuring the young root tips that emerge downward are never in contact with reservoir water before they have established, preventing rot. The 3-inch cube size is also ideal as a transplant block: once rooted cuttings or seedlings have colonised the cube, it drops directly into a 3-inch net pot for NFT, DWC, or drip-fed systems, or sits on a Grodan Grotop slab for commercial slab culture.

Preparing and Using Grodan 3″ Cubes

Soak cubes in a pH 5.5 solution (EC 0.5) for one hour before use to pre-condition the fibres and displace air pockets. Drain thoroughly — Grodan cubes should be damp but not dripping. Insert cuttings to the base of the hole and firm gently. Keep cubes at 22–24°C with high humidity (80–90%) and bottom-water only until roots emerge from the base, typically within 7–14 days depending on species. Avoid over-watering; Grodan’s structure handles moisture distribution automatically when treated correctly.

Use Grodan 3″ Cubes alongside a clone gel such as Clonex, a propagation tray with dome, and a heat mat for the fastest, most reliable rooting results.