Starter Mini-Blocks can sit in a tray (flat) without support for easy starting of seeds and cuttings. Each block of Grodan Mini-Blocks are individually wrapped. For best results put them on the flat side of the Gro-Smart Tray to ensure good airflow around the cubes. Remove wrapping and transplant into any loose media such as Grow-cubes or Grow-Chunks, or leave wrapping on and set on top of a larger Gro-Block. These cubes are popular for production of aquatic plants. The advantage Mini-Blocks have over A-OK Starter Plugs and Macro Plugs is that Mini-Blocks can sit in a tray without support.