Orchiata bark compost perfect for all types of Orchid Plants, recommended by top growers around the world, Retains Structure , Re wets easily, use straight from the bag no need for sterilization, Dolomite addition creates a stable PH adjusted substrate, Produced from sustainable renewable, man-made forests. This orchid compost has been specifically designed for orchids, and both hobbyists and commercial orchid nurseries have proven its ability to produce superior growth on orchid plants. Orchid Compost Size guide Super Grade 18-25mm Extra Large Grade this will suit large Cattleya and Vanda available in 35 Litre Bags only