"]If you want to avoid both peat and coco coir, I know Jerry111165 uses just amended leaf mold but this takes 3-4 years to make" Yes, but if a gardener simply collects their leaves each autumn then by the time the first batch is ready, a new batch will be ready each year and every year after that. It's just that initial wait that's a bitch. Several posts back Rancho Deluxe said that (given the choice) he'd pick quality humus in a soil mix with no amendments vs a heavily amended soil with no humus. This is almost what I'm doing - just about all humus with no (store bought) soil amendments. Of course there's all kinds of kitchen scraps to provide nutrition but the main "food source" in my potting mix is simple comfrey and the results are as good as mixes I've made that had many soil amendments added. NPK? J
Gypsum is not a liming agent. It is a great soil amendment, but will do nothing to help neutralize free hydrogen in the soil solution. You need carbonates for that.
Good looking out man!!! My bad. Silly mistake on my part. Luckily I have no problem admitting when I'm wrong!!! Happens every day...lol. Honestly, I don't have a lick of it in my soil mix. The neat thing about gypsum is that it will interact with aluminum making it less toxic and more easily leached. Here's a pdf for anyone interested in learning more about it. View attachment amending-soils-with-gypsum.pdf
I'll be the very first guy to admit that I'm not a chemist in any way shape or form lol. I know that its the Calcium Carbonate that is needed to change a soils pH but I know for a fact that I've read that somehow, and probably more in certain situations/conditions, that Gypsum can alter a soils pH. I even remember Lumper telling me that in certain situations that it can change a soils pH. If you Google this I see conflicting reports - some say no way, some say yes it can. Can anyone comment on this? j
FWIW, I seem to remember in one of the PDF's (think it was the Acres article), that said that gypsum had only a *slight* effect on pH rather than no effect. But the gist was, it was so slight that it should not be considered as a buffer. I use it and love it, but only consider it as a Ca and sulfur source. That and to help with my red clay everything. Seem to get funny looks trying to buy dynamite for garden tilling. LOL Wet
I for one would be VERY interested in hearing what 'Coot had to say on the subject. From the link that you provided... Gypsum is not a liming agent, however: It does not neutralize hydrogen ions or change soil pH like calcium carbonate does, stressed Ohio State University professor Warren Dick, although this is a common misconception. It can be used to LOWER soil pH in sodic/alkaline soils... Gypsum immediately decreases the pH of sodic soils or near sodic soils from values often over 9 but usually over 8 to values of from 7.5 to 7.8. These values are in the range of acceptability for growth of most crop plants. Probably more than one mechanism is involved. Ca++ reacts with bicarbonate to precipitate CaCO3 and release protons which decrease the pH. Also, the level of exchangeable sodium is decreased which lessens the hydrolysis of clay to form hydroxides. These reactions can decrease the incidence of lime and bicarbonate induced iron deficiency. [SUB](3)[/SUB] http://www.usagypsum.com/agricultural-gypsum.aspx
If you have a sodic soil mix that would be pH altered by gypsum you have far greater problems than which liming agent to use. PW
RD First, WTH is "larf"? I have never heard that term before. Second, gypsum works well as a top dress. I did this last season with my peppers and toms when they were really setting fruit about midway through. So even if you didn't add it to the inital mix you still can if you wish. Wet
So just to clarify so I'm not misunderstanding, in order for the limestone or oyster shell flour to be in usable form, it needs both the sulfur from gypsum along with the microbes? Or 1 or the other? Sent from my LGL55C using Grasscity Forum mobile app
I'm not a chemist either, but a no to sulfur in the gypsum and a probable no to the microbes. I was using lime years before I had even heard of gypsum and I also used lime when running chems. Although using the same basic peat mix. Check out GiMiK's PDF sticky. There are a couple of PDF's on lime, Ca, and how it all works, but does get a bit technical. Wet
Ok I have all those downloaded to a hard drive but haven't gotten past teaming with microbes yet. Ill have to give that one a whirl Sent from my LGL55C using Grasscity Forum mobile app