nobodyhere
Well-Known Member
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.
This is why, even with soil with a ton of N added, and giving copious amounts of N in organic ferts throughout veg and bloom, I still hit most plants with a few doses of grow big first couple weeks into bloom. I don't use a ton of it, but it's there.