Kriegs
Well-Known Member
Dave -- thanks for that link. That should be required reading for everyone who wants to understand their soil better. As you see, "peat" can mean a lot of things. I did my research in natural peat systems with soil pH 7.8 and above, with pure calcium carbonate nodules in it. The soil pore water ranged from 7.0 to 7.6 depending on season and recent rainfall. Sphagnum peat systems, on the other hand, are quite acid overall with soil and porewater values in 3's and 4's. Of course, sphagnum peat is the primary peat in use in horticulture.Heres something for you to read about peat moss.
http://www.dirtdoctor.com/newforum/root/needing-bulk-peat-moss-t8335.html
Its left me a little more confused now haha.
I do know SPM is often blended with compost in soil mixes, so I wouldn't say SPM is killing the good microbes in it.
Im sure UB can shed some light on whether SPM is really sterile or not.
Regarding the yellowing with bronze spots, Ive experienced that multiple times.
I experienced it on one lady, and had no clue what it was. I thought I may have been under-feeding her, so I gave her full strength nutes, and it stopped spreading(still lost the affected leaves), and she is doing great. 5 weeks into flower now, and no more symptoms like that on FS nutes. Nothing else was changed.
Another time, I was over-watering my second batch of plants and they all developed the same symptoms. I cut back on the water, and they all grew out of it.
The third time, my ph pen was fucked up and I was incorrectly ph'ing my water, and they all got yellowing at the bottom with bronze spots, and the upper leaves were still green but with bronze spotting. I quit using the pen, and said "Fuck Ph'ing" and the symptoms went away and they look so much better.
Hopefully one of those are your problems and you can fix it.
Btw, I assume you're using a cal/mag supplement with the RO water. Which makes me ask UB, is there sufficient Cal/Mag in moist soil mixes(amended with dolomite) that a Cal/Mag supp isn't necessary if using RO water?
Regarding cal/mag balance in soils amended with dolomite: that will depend on somewhat on the "dolomite" being used. "Dolomite" is a matrix where the cation positions are part-occupied by Ca, and partly by Mg. The chemical matrix is nearly the same physical structure as calcite -- pure CaCO3 -- but Mg occupies some of those Ca positions in the matrix. It's not a 50-50 split -- true mineral dolomite is about 60-40 Ca to Mg. "Dolostone" is what actually exists in nature, is mined for many applications, and its Ca/Mg balance varies from 10% Mg to maybe 60-70% Mg depending on biogenic origin (pure MgCO3 is very rare in nature).
So, it comes down to whether there are horticultural industry standards for the Ca/Mg distribution in the dolomite used in a soil mix, or produced for addition by the end user. The stuff produced for addition has an analysis on the bag you can consult. I don't know what soil producers who add "dolomite" to their mixes use - I imagine it's some kind of partly refined pelletized material that still retains some of the Ca/Mg variability of the dolostone source. I can't imagine any commercial company expending the money on pure refined mineral dolomite. And then there's the extent to which that industry standard gels with the ideal balance for MJ. Perhaps UB will know if those standards exist and what they are.