* One 4-Quart bag of Uni-Gro Premium Orchid Bark (Fine Grade). * Mixed bark sizes ranging from 1/64" to 1/4" inches * Smaller size is perfect for smaller or seedling orchids. * This Ready-To-Use, 100% Rich, Organic Fir Bark provides excellent drainage. * You can make your own orchid mix by combining this orchid bark with other growing materials such as Diatomite, Hydroton clay pebbles, volcanic ash rock, coconut husk chips, perlite, charcoal, rockwool, and others.