Pringsheim's Soil Water
Select a rich garden soil which has not been recently
fertilized. Add 300 g of
the soil to a gallon jar. Fill three-fourths full with distilled water then add
one gram of calcium carbonate (CaCO3). Plug or cap jar loosely and
steam for one hour per day on each of three consecutive days.
To culture Spirogyra, do not add calcium carbonate. To culture Euglena add
one-fourth of a pea cotyledon before steaming. This will enhance growth. To
culture diatoms, add 10-30 mg of sodium metasilicate
(Na2SiO3 · 9H2O) to every liter of media.