Viagrow plastic grow bags come with one 5 kg Viagrow premium coconut coir growing media. The Viagrow plastic grow bags are economical and easy to use by the residential greenhouse grower. These heavy-duty reusable grow bags are made from PE and are BPA free durable plastic that provides for a longer life. The bags have pre-punched drain holes and they are self-standing when filled with media. Can be used for soil or hydroponic applications both indoors and outdoors. Coconut coir blocks are composed of 3 different types of compressed coconut coir. This high quality, low sodium growing medium is an environmentally friendly alternative to sphagnum peat moss. When hydrated with water, bricks and blocks rapidly expand which saves you time and effort. They can be exclusively used by themselves, blended together or mixed with expanded clay pellets, perlite or topsoil. Coir is not pre-fertilized so it is recommended that you use your choice of dry fertilizer either mixed into your coir or liquid fertilizer with each watering. Color: Black.