Frankly all of this has got me rereading those 5 articles, although only in piece meal fashion so far. They seem to make more sense to me than they did a year ago when I first read them. I should go back and devote some more time to them.
Do we need to pH adjust our nutrient solutions?
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This is a quote from the first page of the massive q&a thread of Docs. I’m not selling the kit or anything but he does seem to strike right at the heart of the earlier discussion regarding the different sources of nitrogen.
He, of course, goes on to discuss the ‘energy’ in soil and how flipping the charge at the right time can have a impact on the plants reproductive capabilities.
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Good find AW!
Thanks man, I want to get better at finding these nuggets and sharing.
Okay, after reading the five articles, and sitting and thinking, I have a question. So we know as indoor growers, especially under LED lights (for some reason), that a lot of calcium and magnesium are typically needed from early flowering/stretch until harvest.
From the articles, the suggested levels of Ca and Mg are 63 ppm and 21 ppm for orchids and most other flowering/fruiting plants. Together, when provided in low-EC RO water, this concentration is within the range of moderate alkalinity, which would suggest a fertilizer with about 25% ammoniacal N.
But if a grower finds that more CalMag is required, and the combined concentration of Ca and Mg, contributed by the CalMag and other nutes, now puts the feeding solution into high alkalinity. A fertilizer with about 40% ammoniacal N is now recommended, in order to balance the higher alkalinity.
Am I reading this right? I have looked at a lot of the popular water-soluble fertilizers, and not many have that much ammoniacal N (Dyna-Gro Grow has ~40%, and Fox Farm Grow Big has ~50%). Even the MSU RO formula (from the articles), only provides ~6% ammoniacal N.
Elvin
Banned Troll
So what happens if we feed CalMag separately from the N? Will the soil buffer it, removing some or all of the need for higher ammoniacal N?
If you are referring to that table in the fertilizers article, it's showing ppm for CaCO3 (Calcium Carbonate) which is different than Calcium Nitrate that is commonly used as the source of Calcium used in the fertilizers and Cal-Mag supplements. CaCO3 makes up the majority of the PPM's of your water from your tap (or other source). You can get a rough estimate by just testing with your PPM pen, or their are test strips for just testing water hardness that can be had in Amazon for about $12.
Thanks Farside!
I knew I was missing something. Of course it’s calcium nitrate.
I knew I was missing something. Of course it’s calcium nitrate.
Thanks for digging thatout Archie! I knew something like it was somewhere there
but it was so long ago I read it all, and went on the relevant tangents of further reading, I wasn’t up to looking for it... so I went on a probably irrelevant tangent of thought that shed’s story and info inspired ... that didnt really respond to the question at hand 
but was definitley connected to that period of reading and research Your method seems much better - i’ll remember that for next time - find the source, don’t get excited speculating on topics beyond the current question (story of my life!
).
No prob AG! . Ive probably forgot more than Ive learned at this point but I did bury myself in his threads for what seemed like months!
. Ive probably forgot more than Ive learned at this point but I did bury myself in his threads for what seemed like months!
@FelipeBlu So in general, if you have fairly standard tap water, 75-200 ppm, you probably should be looking at a fertilizer that is 25-40% Amoniacal Nitrate. RO water, more like 15%. Assuming I am understanding it right myself...lol
Yes, we’re on the same wavelength. I was high earlier and just spaced on the lack of actual carbonates in CalMag.
If using RO, your best bet, to prevent your substrate pH from getting too low, since the DG Grow and FF Grow Big contain far more than 15% ammoniacal N, would be to use a fertilizer with mostly nitrate N (most of them).
If using RO, your best bet, to prevent your substrate pH from getting too low, since the DG Grow and FF Grow Big contain far more than 15% ammoniacal N, would be to use a fertilizer with mostly nitrate N (most of them).
@FelipeBlu . That's what the chart says. I've used Dyna Gro Foliage Pro with RO and Pro Mix for multiple grows with no problems. I've also done MSU fertilizer with RO, which is the optimal match like the chart says. Results we're no better or no worse. Now I'm using the Dyna Gro and tap water, which by the chart, is a good match.
Ah yes, I forgot about DG Foliage Pro, which is ~30% ammoniacal N.
Hey so what type of Nitogen is found in earthworm castings? I have a bag of it here and it doesnt specify.
That info is very hard to find:
Available nitrogen often comprises a relatively high proportion of total N, with very low ammonium-N and very high nitrate-N being characteristic of many vermicomposts.”
Available nitrogen often comprises a relatively high proportion of total N, with very low ammonium-N and very high nitrate-N being characteristic of many vermicomposts.”
I’d put money on it that Doc would know the answer to that question. This whole discussion is pretty much what put him on the trail that led to his current enterprise
Ima ask him!
I agree Amy, I knew this topic sounded familiar.I’d put money on it that Doc would know the answer to that question. This whole discussion is pretty much what put him on the trail that led to his current enterprise
Ima ask him!
I’d put money on it that Doc would know the answer to that question. This whole discussion is pretty much what put him on the trail that led to his current enterprise
Ima ask him!
So I did ask Doc this question because I knew it would be quicker and more reliable than me trying to go through old notes. He gave me a very comprehensive answer, which I’ll share. Caveat being that his perspective is living soil of course, so that’s different to what most of you are doing - but using nutes in soil isn’t a sterile medium either, so its kind of like you have to take a bit from both approaches I guess.
(So it includes his usual “don’t ph” talk - similar to the guy fromProMix - when he says ‘we’ or ‘you’ don’t need to do this or that, he’s directing that at me and using his system in general - i’m using custom ammendment made by him in my outdoor garden).
Just sharing for the info about the nitrogen’s etc. cause it’s well described
Oh and best thing about this scenario is that this answer inspired a whole conversation in that thread about growing blueberries and I now have some great sources of help in that department, which is very needed here. The universe moves in mysterious ways... thanks Shed for helping me out with the blueberry growing!
