Balancing Acidic PH of Peat based Soil?

az2000 said:

What you said was: "i check the ph before it goes in and the run off as well as the fact i know peat by itself has a ph leval of around four."

Literally, I didn't read that to say that you actually measured 4.0-4.5.

Perhaps you have some bad peat. Maybe it has no dolomite. Or, it became exhausted in some way? Left outside, going through wet/dry cycles (getting wet, bag torn, etc?).

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i guess i made no mention of the actual run off or the water goign in my bad, in any case what i stated in teh above post is what goes on.

anyway, yeah the peat is very old, and has been allowed to dry out very much, but there is dolimite and calcitic lime in the mix

Steele_GreenMan said:

anyway, yeah the peat is very old, and has been allowed to dry out very much, but there is dolimite and calcitic lime in the mix

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Apparently not enough. A year ago I did an experiment with 0 to 8 Tbsp/gal dolomite. The first 1-2 tbsp affected the ph the most, raising the ph from 6.2 to 6.4. The additional tbsp didn't raise the ph proportionally. I get the impression it's just there as a larger counterweight against acidification. (I wouldn't try to grow in 8tbsp/gal. It may create an unhealthy environment unrelated to ph. Just giving an example of how dolomite doesn't have to be dialed in. With exhausted peat, I'd do 3-4 tbsp/gal. New pro-mix, I add 1.5-2 tbsp/gal.).

az2000 said:

Apparently not enough. A year ago I did an experiment with 0 to 8 Tbsp/gal dolomite. The first 1-2 tbsp affected the ph the most, raising the ph from 6.2 to 6.4. The additional tbsp didn't raise the ph proportionally. I get the impression it's just there as a larger counterweight against acidification. (I wouldn't try to grow in 8tbsp/gal. It may create an unhealthy environment unrelated to ph. Just giving an example of how dolomite doesn't have to be dialed in. With exhausted peat, I'd do 3-4 tbsp/gal. New pro-mix, I add 1.5-2 tbsp/gal.).

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thanks bud love to hear other peoples insights which is why im on here.

really thanks a bunch! i will definitly keep this in mind when starting my next run

You can get a pretty good idea of what the plant "sees" by watering, let the pot drain for a while, tilting the pot to collect the few drips left in a jigger and IF you have a high quality pH meter that has been recently calibrated with fresh calibration solution, measure to get a fairly accurate reading.

The proper way to measure soil pH is to take de-ionized water, mix it with some soil, shake well, let it sit for a while to settle and stick yo probe in. And no, the ratio of water to soil is immaterial since the water has no ions and is only used as a carrier for the pH meter. You can use 5 parts water or one....doesn't matter.

Having said this, folks in these forums are quick to jump to conclusions that aren't even related and it never fails, if they have some issue (which is usually related to another cause) they automatically conclude they have a pH problem. Cannabis is very pH tolerant regarding nutrient availability. Forget about it and look elsewhere when you have problems.

UB

az2000 said:

Not because of the ph. I thought it was the irregular texture of the soil.

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Still shouldn't be a problem. If you're anal then make a screening tray and screen the soil using a a 2'X2' frame made out of 2X4's and stapling 1/4" galv. hardware cloth to one side of the frame. I use a lot of pine bark for bulk but not to germ seeds.

Uncle Ben said:

Cannabis is very pH tolerant regarding nutrient availability. Forget about it and look elsewhere when you have problems.

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You sir are a King. I don't care what anybody else says about you. This is what I believe, and its great to hear someone else say it.
I found the whole PH thing to be nothing but an unpleasant pain in the ass, and I was never 100% convinced that the readings I would get were truly accurate. I pitch a handful of Dolomite lime in about halfway through a run and forget it. FTS

Cobnobuler, there's a time when we all move outside of the noise zone. Some sooner than others.

Good luck

Just use the right amount of lime when building the potting mix and forget about pH. Use any urea based lawn fertilizer for this type of potting mix.

pH only matters with hydro. In that case, you don't fortify the potting mix with lime at all. Instead, you use a nutrient based on soluble calcium nitrate which should already be pH adjusted.

The reason I do hydroponics indoors is because I'm terrible at guessing how much lime to add to soil/potting mix, although even in DWC, the more experience I get, less often I need to check pH or ppm. I already know what it will be. It's more like an inspection now, like making sure the airstones lines aren't pinched.