1" Grodan SBS / Rockwool Starter Cubes

Our Price: £7.00

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The Grodan 1" cubes come in a tray of 150 or as a whole box. The cubes are a sterile growing medium and an excellent way to start your seedlings or cuttings. The Grodan cubes need to be conditioned or soaked before being planted up. See BELOW for a great video on how to condition different sizes of cubes.

  • Suitable for flower and vegetable propagation
  • Control range 55 – 80%
Grodan Delta forms the foundation for uniform and perfectly controllable propagation of plants – an absolute condition for vigorous and healthy plant growth. Each block has an identical density, flexibility and sturdiness, guaranteeing even distribution of the WC, EC and pH. The result is a uniform and high-quality plant. 

Grodan Delta is the best block for essential properties such as firmness and saturation. These qualities make Grodan Delta ideally suited for propagators who want to secure the success of their processes.


1. Effortless start up of propagation
Grodan is the perfect block for propagating young plants under a wide range of propagating conditions. The block is easy to saturate and water is distributed uniformly throughout the block, so reliable and vigorous plant growth is guaranteed. 

2. Uniform WC and EC distribution
Based on the Delta Technology, the structure of the block and water distribution throughout the substrate have been improved. Newly transplanted plants will benefit thanks to the ready availability of water and the balanced nutrient solution (EC), encouraging the roots to penetrate deeply into the blocks.

3. Easy WC management
The water content levels can be easily managed between 55% and 80%. This applies equally to low and high water content levels. If the moisture content level threatens to drop too low, it can be simply be restored to the desired level, for instance 80%. Thanks to the variations in the small and large pores, the roots are always guaranteed a sufficient supply of air and water.

4. Excellent root growth throughout the block 

The Delta Technology ensures uniform distribution of water and nutrients throughout the block. Newly transplanted plants will benefit thanks to the ready availability of water and EC, encouraging the roots to penetrate deeply into the slabs

5. Greater firmness for better handling

As mechanisation has been increasingly introduced into the propagation process over the years, the blocks must be able to withstand handling better during propagation. The stable firmness of Grodan Delta becomes particularly important when the blocks are placed, spaced and picked up several times during propagation. An added advantage is greater protection for the roots during transport from the propagator to the grower.

View the Grodan Delta Brochure in PDF of Grodan Rockwool
A great informative video by manufacturers Grodan on how to condition different sizes of their rockwool cubes.