Organic growing can be accomplished via either soil-based or lower-volume soiless systems. Soiless organic growing systems have been discussed in detail in previous articles. However, as a brief synopsis, soiless systems use materials such as perlite, pine bark, coconut core, compost and sawdust as a growing media, just to name a few, and these systems are usually found in a greenhouse growing environment. As in all growing systems, proper fertilization of the plants is key to healthy and vigorous growth and optimal production. In the case of a soiless media system, the type of media used plays a role in determining what fertilization is needed. The microorganism present in the media have the job of breaking down the various fertilizer components so that they are readily absorbed through the plant roots There are some challenges to supplying fertility in organic low-media-volume production systems.