Great for starting seeds or clones. This Styrofoam insert tray that holds 55 Super Starter Plugs. Because the Styrofoam base floats delicate roots stay above the water line making it suitable for seedling or cuttings. Super Starter Plugs are made of composted tree bark with a natural polymer that retains a perfect air to water ratio which maximizes water retention and nutrient exposure. Once the plants are rooted, the insert can be placed directly in to an Ebb & Flow hydroponic system or be planted in soil.