Gypsum as a soil amendment
- Thread starter rkmcdon
- Start date
Richard Drysift
Well-Known Member
Use the ag grade. It won’t wash out; you don’t need very much either. Good for promoting healthy fungal growth and as a source of calcium. A handful is about enough for a 60gal tote of soil.
Thank you. I have a much cheaper source for the ag grade as well so was hoping it was the best option. Its good to know it will hang around. I've found one of the big challenges as i read up on amendments and try to plan a course of action is finding out both how quickly an amendment will start providing nutrients and how long it will hang around. It seems that information is often not readily available
im trying to convert slowly to organic and I agree. Cant find it no where but I guess it all depends on your soil biology.
Not as a liming agent. Gypsum is the wrong form of calcium (sulfate), to affect pH, where the carbonate form is needed.
I use both, but for different applications.
Wet
And that's exactly why i included it as well. We used to foliar spray sulfur regularly but that is tedious, time consuming and kills my predator mites, so I went with a soil recipe that includes both gypsum and langbeinite
This is not the oyster shell sold for chicken scratch, is it? That is pretty much useless for buffering due to its screen size. Way too big.
Oyster shell flour has about the same consistancy as all purpose flour as does pulverized lime. This is what you want for pH.
Wet
Yes, i have oyster shell flour from redbud soil company in okc
I was looking at this to to use instead of Dol. Lime mixed with sulfur (i use 1tsp/gal organic soil each)
https://www.ebay.com/itm/1lb-GYPSUM-Calcium-Sulfate-Water-Softener-Increase-Acid-Homebrew-Beer-Mead-Cider/142870541666?hash=item2143bf7562:g:9mUAAOSw03JcrhWQ:sc:USPSPriority!89183!US!-1
It's all Calcium Sulfate dihydrate right?
https://www.ebay.com/itm/1lb-GYPSUM-Calcium-Sulfate-Water-Softener-Increase-Acid-Homebrew-Beer-Mead-Cider/142870541666?hash=item2143bf7562:g:9mUAAOSw03JcrhWQ:sc:USPSPriority!89183!US!-1
It's all Calcium Sulfate dihydrate right?
LinguaPeel
Well-Known Member
Yea i checked lowes, hd, ace dont need 40lb lol but only lime in stock here at lowes. How much do you generally need per gallon soil? I cut kellogs patio organic potting with peat n perlite so it will have no food in less than a month. For outdoors we have a ton of calmag in our water so i am not worried
I use 1 cup of Gypsum per 12 gallons of soil (I mix 48 gallons at a time).
you can get gypsum in smaller quantities off of amazon
Espoma GG6 Garden Gypsum Fertilizer, 6-Pound https://www.amazon.com/dp/B00AE23XOY/ref=cm_sw_r_cp_api_i_Yad4Eb2KR21C0
you can get gypsum in smaller quantities off of amazon
Espoma GG6 Garden Gypsum Fertilizer, 6-Pound https://www.amazon.com/dp/B00AE23XOY/ref=cm_sw_r_cp_api_i_Yad4Eb2KR21C0
radiant Rudy
Well-Known Member
Gypsum is a good source of Ca for neutral to alkaline soils. It can help with aeration when Mg is in excess. It can also help with displacing K in situations where there's been over use of compost, castings or seaweed. Almost everyone needs more calcium.
As far as dosages you should start with a soil test so that you have a solid basis to use for decision making.
A handful of gypsum in 60 gals of media would produce no effect. I'm getting ready to flip a plant that has been recently potted up to 5 gal. To encourage root growth and set it up for flowering today i dosed it with 50 grams of gypsum in 2 gal of 0 ppm water. My pH is 7, my Mg is kinda high, and the additional Ca is welcome. If i had 60 gals of this same substrate i would use ~600g or 1 and a quarter pound.
Look for gypsum with high purity. Impurities like Na and Fe could be a problem. Ebay has inexpensive, solid, lab grade CaSo4.
As far as dosages you should start with a soil test so that you have a solid basis to use for decision making.
A handful of gypsum in 60 gals of media would produce no effect. I'm getting ready to flip a plant that has been recently potted up to 5 gal. To encourage root growth and set it up for flowering today i dosed it with 50 grams of gypsum in 2 gal of 0 ppm water. My pH is 7, my Mg is kinda high, and the additional Ca is welcome. If i had 60 gals of this same substrate i would use ~600g or 1 and a quarter pound.
Look for gypsum with high purity. Impurities like Na and Fe could be a problem. Ebay has inexpensive, solid, lab grade CaSo4.
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Yup thanks i think brew grade is food grade i hope
meangreengrowinmachine
Well-Known Member
So in general you would say this should be applied at a 1 gal to 10 grams ratio. Should I apply this to my soil prior to it cooking down along with my other amendments? (Sorry I know this thread is pretty old)
radiant Rudy
Well-Known Member
If you know for sure that your mix needs Ca and S cooking it in is a good idea. You would need to estimate the application volume based on the mix ingredients or a soil test. If your mix is sufficiently acidic and you primarily want calcium, and you have time to cook, it may be wiser to use CaCo3 or Ca₂O₄Si or diatomaceous earth.
When i pot up in veg I will sometimes give a drench using >50g in 2 gal. of RO water to encourage root growth. Gypsum doesn't change pH and isnt rough on soil biology.
If you do some digging you can find loads of agronomic research on gypsum. The slow nickel thread over on IC is exhaustive.
When i pot up in veg I will sometimes give a drench using >50g in 2 gal. of RO water to encourage root growth. Gypsum doesn't change pH and isnt rough on soil biology.
If you do some digging you can find loads of agronomic research on gypsum. The slow nickel thread over on IC is exhaustive.
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