CocoTek? Premium Coir is naturally free of bacteria, plant disease, fungal spores, weeds, seeds and pathogens. General Hydroponics? CocoTek? growing medias can be used by themselves, blended together, or mixed with expanded clay pebbles, perlite, topsoil, or any other growing media. CocoTek? PX is premixed with just the right amount of treated coir and perlite to provide aeration and optimum moisture retention. Ready to use right out of the bag, simply fill your container, plant, feed and get growing.