: Rockwool has a naturally high pH (around 8.0) that can lock out nutrients. You must soak the cubes in slightly acidic water (pH 5.5 to 6.5) for at least an hour before use.

: Smaller 1-inch cubes are ideal for smaller propagation trays or starting seeds that will be moved quickly to a larger medium. : ~$18.99. .N/A 72PCS 1.2 in. Rockwool Cubes with Net Cups Go to product viewer dialog for this item.

: For more advanced setups, these larger blocks can be used for soilless cultivation or cut into custom cube sizes. Price : ~$56.72 (2-pack). Why Choose Rockwool?

: This is a complete starter kit that includes both the rockwool cubes and 56 plastic net cups. : ~$61.51.

: These are durable and designed with pre-made holes for seeds or cuttings, helping foster healthy root systems. : ~$21.99 - $36.99 (for a 4-pack of sheets). VIVOSUN 1 in. Rockwool Starter Grow Cubes Go to product viewer dialog for this item.

: Since it is manufactured at extremely high temperatures (3,000°F), it contains no pests, diseases, or weed seeds.

Buying rockwool cubes at Home Depot is a reliable way to source a sterile, high-performance medium for hydroponics or seed starting. These cubes, made from molten basalt rock spun into fibers, offer an ideal air-to-water ratio that promotes rapid root development.