Soil Mixture Components
Place of Learning: 

ESY Berkeley Teaching Staff
Edible Schoolyard Project
Berkeley, CA

When choosing ingredients for making a good potting mix or when selecting a potting soil mix that is already made, check to make sure the ingredients of the mix you choose are organically grown so that no toxins or chemical sprays are present in the ingredients you are handling. Here is a list of our favorite chief ingredients commercially available.
Coco Peat

This product is a reliable renewable-resource alternative to peat moss, which is mined from ancient peat bogs. Organic and biodegradable, Coco peat is made from the husk fiber of coconut plants and provides nutrients and water storage as well as disease resistance when added to seedling potting mix. The coconut plant annually sheds its bark so this product is a true renewable resource.


This product is made from mica rock, which is puffed under pressure and 2000° heat to create a soilfree product that increases aeration, as well as nutrient retention and exchange.


This volcanic rock product is produced by heat-popping lava rock. Perlite helps in soil drainage and is an excellent medium for rooting plant cuttings.

Peat Moss

This is a generic term for any plant that partially decays underwater. Most gardeners use sphagnum peat moss gathered from Canadian peat bogs. This product is extremely retentive of water and has excellent antibiotic properties. However, peat moss is being rapidly depleted by mining the ancient peat bogs where it is found.

Wood Products

There are numerous sifted wood products that can be useful in potting mixes. If you choose these materials look for products made from decayed bark rather than from sawdust since bark decomposes more quickly and does not tie up nitrogen-loving bacteria in the same way that wood chips or sawdust tend to do.