Medium-grade Dyna-Rok II is a versatile, absorbent, earth-friendly
growing medium made from the fossils of ancient single-celled plants
called diatoms. These fossils are a natural source of silica and
growth-boosting minerals, part of which get absorbed by the plant over
time. The majority of the medium doesn’t decompose, however, holding as
much as 150% of its total weight in water or nutrient solution. This
makes medium-grade Dyna-Rok II an excellent choice as a stand-alone
medium or as a soil amendment. This 9.1 qt bag contains enough growing
medium to fill approximately four #1 nursery pots.