I have been experimenting for one year now with expanded clay pellets size 2-4 mm. Since then i harvast more and can put different type of plants in the same system. Tomatos, lettuce, pak soi and white cabbage, all grow in the same growbed. Now i am experimenting with clay pellets size 1-6 mm. Now i can sow directly in my grow bed and don't have to transport my cuttings from one grow bed to another.