Calcium and Magnesium source a concern?

[Orchid Whisperer]

Originally Posted by snowflake3111

I have not found orchids care much about Calcium or Magnesium your all around orchid fert should have it so no need to add more IMO. Orchids do not need as much ferts as most house plants. Orchids do like Nitrates aka Nitrogen. So that would not hurt. Some orchids do need more Calcium than others. It really depends on the type of orchids you grow I think.

I grow another type of plant that is a Magnesium HOG. I feel like this plant can not get enough of the stuff. Orchids are nothing like this plant.

It depends on your water supply, the type of fertilizer, and the type of orchid. If your water supply provides Ca and Mg, or your fertilizer contains these elements, great! Many water supplies, and many fertilizers, in the United States do not supply enough, and supplemental Ca and Mg are needed. You can tell when a deficiency exists (chlorosis as previously stated, disease susceptibility, etc.)