Cal and mag use eachother or need eachother to be ?properly? Absorbed maybe this is why they are commonly deficient at the same time....from the top of my head plant uses atleast 3x more calcium then magnesium...
Ca and Mg play different roles in soil structure and in the plant, but the more important element of the two here is Ca. Ca, in order to be utilized properly, requires sufficient amounts of available B (boron) but only a little is really needed. Your observations closely mirror mine, the plants need at least 3x the amount of Ca as opposed to Mg in most scenarios. But what I've learned by separating the feeds (when I was doing chem salts) was that I could
easily alternate those feedings, heavy on Ca one feeding, then Mg another, and the plants performed very well.
Really, what this is about is
balancing your feeding, watering, media, and environment.
Goo..I think mainly, she is supporting the theory of people having a Calcium deficiency or Magnesium deficiency rather than both at the same time..more or less to draw a line. Although, I don't think it is impossible to have both deficiencies at the same time though. And her point, is definitely not that plants do not require Cal or Mag, but more to the point that every deficiency shown is not always a Cal or Mag deficiency, but more to the point it could be another nutrient lacking or over applied.
I would get some more Cal-Mag and have it on hand, especially for RO and especially for OG.
Well now here's the thing, you can observe both deficiencies, but they are not one and the same thing. That's why I discussed what a Ca- looks like vs a Mg- because they are different in terms of mobility, and therefore present differently. That doesn't mean they don't 'need' each other, all the elements are needed in their various forms, but again, what we need to learn is balance.
Reverse osmosis water has been stripped of
all minerals, many of those in the form of carbonates or bicarbonates that essentially lock Ca up. For example, my own well water is very high in carbonates, and I figure that, due to the presence of a cave nearby that features Ca-based crystal structures, it's likely that a good portion of the carbonates are CaCO3, perhaps MgCO3. I have tight, heavy clay soils, indicating a strong presence of Mg but little Ca (Mg causes soils to 'tighten' up, whereas Ca causes them to 'loosen' up, become easier for plants to penetrate). When trying to grow simply using my untreated tap water as the main source for Ca and Mg, I failed miserably. Once I cleaned (stripped via RO/DI) the water and then
added back those essential minerals in an
available form, things went much better. Then I separated Ca from Mg and the learning curve got STEEP. Turned out that The White isn't a
Cal-Mag whore, she needs CALCIUM, and lots and lots of it, as an example (so you growers who do a lot of OGs that you think need lots of
Cal-Mag, maybe what they're demanding isn't the combination as much as it is the one more important element of Ca).
K, off to read some more, I don't want each post to get too long and I've got a problem with that anyway. D'oh! :o
