Dirt ph

DWCgrower406

Well-Known Member
Doing a few outdoor this summer, actually my first time growing in dirt, always been indoor dwc. I bought a few bags of dirt, glacier gold growers blend. Really popular stuff around here (montana, flathead valley), everybody seems to swear by it. Started a few plants in pots. They are doing ok but not perfect, maybe a bit overfed. I am not feeding anything but ph'd water but i figured the new dirt might be a bit hot for young plants. Watered and checked runoff, pretty high, 2000ppm and pretty acidic at 4.5ph. I ph'd some water to 8 and flushed pretty good, got ppm down to 1000 but ph barely budged, still 4.6. Just to make sure im not dealing with other factors i took a fresh quart of dirt straight from the bag and mixed up a slurry with ro water. Same acidic result, 4.5ph.
Why is the dirt so acidic? Did i get a bad batch or would there be a reason for this? Maybe local water is typically alkaline and they are trying to account for that? Even if that was the case, i couldnt get it to rise by flushing with 8.0 water. Any thoughts? I can buy different dirt, i just dont understand because everyone loves this dirt. Plants do look better since flushing the ppm down, but if 8.0 water resulted in 4.6 runoff, the root zone must be terribly acidic. Am i missing something?
 

Snoopy808

Well-Known Member
Im as confused as you are! Its not uncommon to get bad batches of soil.

Dolomite like is a great pH up buffer. Will buffer to 6.8-7.0 and provide cal snd mag. Works well to open up heavy clay soils.
 

DWCgrower406

Well-Known Member
Im as confused as you are! Its not uncommon to get bad batches of soil.

Dolomite like is a great pH up buffer. Will buffer to 6.8-7.0 and provide cal snd mag. Works well to open up heavy clay soils.
I ended up transplanting into 7gal air pots with some good dirt from hydro store. Originally was in 3 gal and tried to remove as much dirt as possible during transplant. Did the slurry test on the new dirt and it was bang on where it should be, about 6.4. Not sure what was up with the other dirt, but hopefully the new stuff will balance it out. Air pots now have probably 2 gal old stuff, 5 gal new stuff, and the air pots should allow more frequent watering to flush out that acidity
 
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