The Delta block is used as part of a slab system. The blocks are pre-drilled to hold an A-OK cube used in propagation (seeding or sticking). The A-OK is simply placed in the hole in the Delta block. Once the roots have filled the Delta, it is set on top of a slab or Big Mama block for the rest of the production cycle. Deltas can be irrigated with drip, hand watering or via sub-irrigation. Water holding capacity is optimized for young plants, encouraging strong root development. No-hole versions also available. Commonly used with high wire crops (tomato, cucumber, pepper) and roses.