The Spurway extract is a weak acetic acid extraction of the potting media. A representative sample of the media is seived through a 2 mm seive to remove the larger pieces of bark, stones and other relatively inert materials. A 5 cc subsample is placed into a 50 mL Erlenmeyer flask and 25 mL of 1% acetic acid solution is added with a volumetric buret. The mixture is shaken for 1 minute and then filtered. The filtrate is analyzed for important plant nutrients: nitrate and ammonia levels are determined by colorimetry, and phosphorus, potassium, calcium, magnesium, sodium, iron, manganese, zinc, copper, molydenum, and boron are analyzed by ICP-AES. Results are reported as ppm (mg/L) in the media extract. A separate 15 g subsample is wetted with 75 mL of deionized water, stirred every 10 minutes for 40 minutes and the solution analyzed for electrical conductivity. The media pH is determined on a separate 5 cc subsample that is wetted with 5 mL of deionized water, allowed to stand for 15 minutes, and the pH determined using a pH meter with reference and glass electrodes.

Our Methods

Link to Our Methods