| I, too, raise orchids and I'm with Steve and Mike -- you need to keep looking for the cause of death.
Orchids require very, very low levels of fertilizer. Our mantra is "fertilize weakly weekly." And while commercial orchid fertilizers can contain copper (the label on the one I used yesterday says .05% chelated copper) the drip through amounts of copper would be absolutely miniscule.
Inexpensive test strips are available to test your pond water for copper. Always test (don't guess) when your koi are at risk. |