Effects of Varied Soil Composition (Char, Sand, Potting Mix) on the Growth of Radish Starts


Bear Kaufmann. Initially posted April 7, 2008. Updated August 5, 2008.

Images showing trial preparation and radish germination
(Select image to enlarge in Gallery.)


Char was Lazzari Brand mesquite BBQ char (due to availability), crushed and screened to 1/8".
No nutrients were added to the char itself or to the soil.
Soil was FoxFarm OceanForest Potting Soil.
Sand used was horticultural sand.
No mycorrhizal fungi were added.
Mixtures range from 0-100% sand, soil, and char in ~16% increments by volume. 90 pots total. 28 combinations with 3 pots each + 6 additional pots at 33%/33%/33% composition. Pots were placed randomly within the tray. Tray was rotated 180