Saturated Media Extract (SME)

The Saturated Media Extract is a water extract of the entire media sample. No attempt is made to sieve the sample before analysis. A representative sample of the media is wetted with deionized water until water just barely stands on the surface. The mixture is allowed to equilibrate for 90 minutes and then filtered under suction.

The filtrate is analyzed for important plant nutrients: Nitrate and ammonia are determined by colorimetry, and phosphorus, potassium, calcium, magnesium, sodium, iron, manganese, zinc, copper, molydenum, and boron are analyzed by ICP-OES. Results are reported as ppm (mg/L) in the media extract.  Electrical conductivity is also determined on the filtrate.

Media pH is determined on a separate 10-cc subsample that is wetted with 10 mL of deionized water, allowed to stand for 15 minutes, and then measured on a Mettler Toledo Seven-Multi pH meter with an InLab Routine Pro combination electrode.