UPuper® 4-inch Rockwool cubes are a good size for transition planting (transplant) or finishing small plants, and they feature a standard-size rockwool pre-cut (planting) hole for easy (easily) transplanting of seedling starts.They can effectively retain moisture, and their unique 4-inch size provides the minimum processing capacity for optimal activity. They are also very suitable for storing water or additional nutrient solutions required for root system interactions.The water absorption capabilities of rockwool cubes also create a stable growing environment, as it is able to hold steady moisture levels between 30-40%, preventing rapid air humidity changes.