Grodan MM40/40 Cube

These cubes are designed as an intermediate step for seedlings. They provide a stable environment to hold young plants after they have outgrown smaller starter plugs but before they are ready for final transplanting into slabs or larger systems.

While they are intended for transplanting seedlings, they can be used for starting seeds. However, because they are larger than standard starter plugs, they are most efficient when used to house plants that have already begun to develop a root system.

The MM40/40 cubes are engineered for high moisture retention, which helps prevent the root zone from drying out too quickly. You should monitor your plants closely, as the medium will hold water longer than traditional soil or less dense substrates.

Grodan stone wool is chemically inert with a neutral pH. While the cubes themselves do not alter the pH, you should always ensure your nutrient solution is adjusted to the specific requirements of your plant variety before saturating the blocks.

Yes, their standardized 1.6-inch dimensions make them highly versatile. They fit well into most standard propagation trays and are easily transferred into larger rockwool slabs or other hydroponic setups once the roots have established.