Container Substrates

potting mixContainer substrate characteristics influence irrigation and fertilization frequency.  Different substrate components hold water and nutrients to varying degrees. An ideal potting substrate holds a large amount of water and at the same time retains air pockets (porosity)in the plant root zone to encourage oxygen. Substrates with lower nutrient holding capacity will require fertilizer more frequently. Media with lower water holding capacity will likely require extra fertilizer and irrigation.

Typical container production media contain a mixture of sand, pine bark, and often small amounts of peat moss. Sometimes vermiculite and slow release fertilizer like polyon or osmocote may be incorporated into the media as well. The major component, pine bark, does not extensively hold nutrients.


Researchers from North Carolina State University and Oregon State University are addressing the need for alternatives to pine bark substrates by examining various alternative substrates.

Alternative Substrates NC State logo

NCSU Research


Alternative Substrate Research Groups

THE NCSU TeamNorth Carolina State University Reserachers

Elizabeth Bridges-Graduate Research Assistant

Dr. Bill Fonteno

Dr. Helen Kraus

Dr. Ted Bilderback

Dr. Brian Jackson