Has anyone heard of Gypsum (hydrated calcium sulfate) for lowing the pH in soil? I'm growing in Virginia. My plants are Diesel Elvis #5 and Crack Weed. The soil is regular potting soil but I amended it with perlite, vermiculite and sphaghum moss. The nukes I use are Jacks Classic All Purpose 20-20-20, SuperNova 1-1-1, Black strap molasses, Peruvian seabird guano 10-10-2 and Alaska Fish Fertilizer (5-1-1), I recently stop using the fish fertilizer because my girls are getting slightly dugged up by animals. I think the fish fertilizer is attracting them to the plants. I am going to buy seaweed at the end of this week and start using that also. Some of my girls are 6 feet tall and others are 5 feet tall. Others are only 3 feet tall but they are in desperate need of transplanting which is slowing them down. I am in the midst of moving them again due to security issues, so it's really hairy now because they are so big. When things are settled and they are transplanted, I am going to take a pH reading. If the pH is too high, which I don't think so now, I wanted to know if anyone has heard of Gypsum (hydrated calcium sulfate) for lowering the pH level? I want to buy something now and keep it around in case I need it. I read about this in Jorge Cervantes' book Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible. Any help would be greatly appreciated. Thanks.
Has anyone heard of Gypsum - Hydrated Calcium Sulfate?
- Thread starter hey1
- Start date
OldMedUser
Formerly Known as LabRat
First off the gypsum will raise not lower pH.
Industrial gypsum is contaminated with heavy metals and all sorts of crap. Here in Canada it is classified as hazardous waste and must be disposed of in a secure land-fill.
I wouldn't use it and I wouldn't want to smoke any herb that was grown in it.
Zoidberg13
Active Member
+1
Gypsum is a very poor choice for a direct soil additive. BUT. I believe if it not processed it is a GREAT additive for the first run of a compost pile.
The compost I use for my indoor soil blends is composted a minimal of four times. So any crap in Gypsum or toxins is not a significant ppm.
God Bless
