GRODAN BOX 4″ CUBES (SMALL HOLE 25MM)

Description

GRODAN BOX 4″ CUBES (SMALL HOLE 25MM) are the larger-format Grodan propagation and early-stage growing blocks that bridge the gap between small starter cubes and full-size grow slabs. We have been supplying Grodan rockwool products to UK hydroponics growers since 2017, and the 4-inch cube is the definitive transplant block for growers moving rooted cuttings or seedlings into their main hydroponic system.

The Role of the 4″ Cube in the Hydroponic Cycle

After a cutting or seedling has rooted in a 1.5″ or 3″ starter cube, the next stage is to transplant into a substrate large enough to support rapid vegetative growth until the plant is ready for its final position on a Grodan grow slab or in a large pot. The 4-inch cube provides enough volume for a week to ten days of strong root development while remaining small enough to allow the root system to colonise the entire block before moisture retention becomes an issue. The small hole 25mm insert accepts the standard 3″ starter cube directly — simply drop the rooted starter block into the 4″ cube’s insert hole and the root system transitions without any transplant check or disruption.

Preparing and Managing Grodan 4″ Cubes

Pre-soak in pH 5.5–5.8 solution at EC 1.0–1.2 for one hour before transplanting to condition the cube and provide an immediate nutrient supply. Position cubes on a well-draining tray or directly on your growing channel and begin feeding at your standard early-veg feed rate. Avoid over-watering — Grodan cubes hold water efficiently and roots benefit from slight wet/dry cycling to promote downward root growth. When significant root emergence is visible from the base, transplant to a grow slab, DWC net pot, or final container. The box format keeps cubes organised and undamaged during storage.

Use Grodan 4″ Cubes alongside Grodan SBS Small starter cubes and CANNA Aqua Vega A&B for a complete, professionally managed rockwool propagation-to-production system.