Penningsfeld Medium

Originally cited by Penningsfeld, 1990. Anzucht und Ernährung  heimischer Orchideen. Die Orchidee, 41, 185-8, and 221-5. 

Ca(NO3)2 * 4 H2O  80 mg  KCl  160 mg  KH2PO4  80 mg  MgSO4 * 7 H2O  80 mg  NaFeEDTA  25 mg  Starch  10 g  Agar-agar  10 g

Adjust pH to 6.0.

Source: Rasmussen, H. Terrestrial orchids from seed to mycotrophic plant. Cambridge University Press, Cambridge. 1995.