Cal Mag for rain and RO water users

crust

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So, what Cal Mag are rainwater and RO water folks using and at what rates?????
 

crust

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When using porous substrates to grow potted trees and not using well water, but rather, water derived from a reverse Osmosis filter or from collected rain, one can and does suffer from calcium and magnesium deficiencies and also microelement deficiencies. The microelement deficiencies are easy to deal with however the Cal/Mag is more difficult because it is needed in larger amounts. Typically solutions can be bought and added to the water ( Examples: Cal/Mag plus from Botanicare, General Organics CaMg+) Also the use of Epsom salts can take care of the Mg. Ca is be added separately also. Just want to keep things simple and wondering what others are doing.
 

Bonsai Nut

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It means if you are using rainwater or reverse osmosis water (RO water) your water will not have any minerals. He is asking what Calcium and Magnesium people add to their water supply - and at what rates.

Since I live in Southern California, our water has so much calcium in it you can almost walk on it :) However I do supplement my trees with magnesium in the form of magnesium sulfate, particularly in the summer when salt levels in our irrigated water are high. I would have commented, but since I don't actually add supplements directly to my water, I'm not sure it would be the information the OP was looking for.

[EDIT] Crust and I posted at the same time. [/EDIT]
 

hemmy

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@Bonsai Nut, doesn't your hard water also have magnesium in it? I've seen the recommended ratio of Ca to Mg at between 3:1 and 5:1. Are you adding it for the magnesium or also for the sulfate to lower the pH?
 
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