Grow-Cubes are small 1/4” cubes of stone wool (stone wool). There are several advantages:

  • Grow-Cubes stack on top of each other leaving air space in between them this promotes root growth.
  • Each cube has four surfaces from which excess water can drain. This way, even if you water a lot, the Grow-Cubes will not get water logged.
  • You have less algae growth on the top than with the smooth surface Gro-Blocks™.
  • The Grow-Cubes are the driest of our products with properties of a 50/50 mix. (50% water/50% air)
  • Very easy to mix with any other potting mix.
  • Special advantages are achieved by mixing Grow-Cubes in with clay pellets. The Grow-Cubes will help spread the water in the container as well has keeping a water buffer in between the watering.
  • Lightweight; approx. 1/10 of the weight of a bag of potting soil.
  • See Grow-Cube growing guide right for easy instructions.
Specification Chart: 
Grow-Cubes Volume Weight
Big Bag (2 cubic ft.)

Fills approx. 23 standard one-gallon nursery pots*

5 lbs

Medium bag (1 cubic ft.)

Fills approx. 10-11 standard one-gallon nursery pots*

3 lbs

*Note: A one gal. nursery pot does not hold a full US-gallon.
The approx. volume is 88 oz.

Grow-Cubes are also available loose in a case: 5.29 cubic feet (150 liter)