What PH should my water be?

rockso15

rockso15

Member
I just started wifh my first gro, I am aware of the basics of how things work lreett much but I am still having a hard time figuring out the PH checking.

So as far as I figured it out from reading some posts, you should aleays test the runoff (with distilled water that is 7.0 PH neutral) and not the soil itself.

So if my runoff is 5.5 PH, and my water (after adding nutes) is 6.5 PH, how much should I increase/decrease the PH of the water?

Should I increase it to 7.5 PH?
 
DCcan

DCcan

Well-Known Member
rockso15 said:
I just started wifh my first gro, I am aware of the basics of how things work lreett much but I am still having a hard time figuring out the PH checking.

So as far as I figured it out from reading some posts, you should aleays test the runoff (with distilled water that is 7.0 PH neutral) and not the soil itself.

So if my runoff is 5.5 PH, and my water (after adding nutes) is 6.5 PH, how much should I increase/decrease the PH of the water?

Should I increase it to 7.5 PH?
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Probably should ask what you growing in since soil will not usually need any PH adjustment vs drain to waste.

PH the water going into the pot, not PH coming out. PH of the water going to the roots is important, changes by the time it gets to the bottom, so its pointless to test afterwards.

You check the runoff coming out of the pot for PPM/EC to see available nutrient levels in medium.
 
rockso15

rockso15

Member
I
DCcan said:
Probably should ask what you growing in since soil will not usually need any PH adjustment vs drain to waste.

PH the water going into the pot, not PH coming out. PH of the water going to the roots is important, changes by the time it gets to the bottom, so its pointless to test afterwards.

You check the runoff coming out of the pot for PPM/EC to see available nutrient levels in medium.
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I do soil atm. I came across numerous post and articles saying you should not check ph of soil by putting ph meter in soil but rather test the runoff, which actually makes sense cause top soil cannot match rest of the soil cause gravity pushes salts downward.
 
rockso15

rockso15

Member
MickFoster said:
A slurry test is the only way to accurately test the pH of soil.
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I think the runoff test comes somewhat close to the slurry test, but my question again is runoff or slurry, if my result is 5.5ph from the test, what ph should be my water (after mixed nutes)
 
C

cage

Well-Known Member
rockso15 said:
But my question is I repeat, if my slurry test is 5.5ph what ph should my water be
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I'd still give that 6.5-7 pH'd irrigation water with decent run off.
The soil has buffering capacity so it might take a while to stabilize after changes.

Like if your nutes consist alot of ammoniacal nitrogen instead of nitrate nitrogen, your pH would drop as the plants consumes the ammoniacal nitrogen which is cation.
But as other pointed out, it's no biggie in soil with good runoffs and proper pH to start with.
 
rockso15

rockso15

Member
cage said:
I'd still give that 6.5-7 pH'd irrigation water with decent run off.
The soil has buffering capacity so it might take a while to stabilize after changes.

Like if your nutes consist alot of ammoniacal nitrogen instead of nitrate nitrogen, your pH would drop as the plants consumes the ammoniacal nitrogen which is cation.
But as other pointed out, it's no biggie in soil with good runoffs and proper pH to start with.
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I do a good runoff with my diy airpots, actually the pots are just 1 gallon so the soil kinda started to be hydrophobic and the inly way to water properly is to dip the airpot in the bucket with nutes, plants seem to really love it, they did until recently I did ph up to 8.0ph watering and some started to curl up and started to dry (7th week flower) just a few out of 60 plants in my sog.

My thought is that it is either ph (runoff is 4.8ph which is pretty bad), either salt build up because of the dip watering (which is also ph thing again cause salts lower ph), or just the 1 gal pots being too small (i intended to have smaller plants in my sog but I let them in veg 10 days more than I should)

I dunno, its my first more serious grow so I am still learning a lot
 
Tolerance Break

Tolerance Break

Well-Known Member
I think your intuitions are correct.

As someone who bottom feeds rockwool, I flush ever 1 to 2 weeks to keep the salts from building up. I know soil is different, but the principle remains the same.
 
tstick

tstick

Well-Known Member
Man, I had this exact problem with my last grow. I'll tell you what fixed it....

I had mixed up my soil(less) mix and thought it was good, but my plants started looking badly deficient at about 3 weeks into veg. I knew the mix had plenty of nutes in it so it couldn't be a deficiency. Then, I decided to do a runoff test just for kicks....WOW! The pH of the runoff water was 4.0! I then did a slurry test and the results confirmed that the pH was waaaaay too low. Okay, so then I knew what the problem was....but how to fix it???

I pH'd my incoming water to ~8.0 and ran several gallons through the pots until I started getting a runoff reading closer to 6.5. After that, I adjusted the incoming water's pH to ~6.0-6.5. After about a couple weeks, the plants rebounded and then I went to a regular feeding schedule of Jack's 3-2-1 and made sure the nutrient-solution was also pH'd accordingly. After that, I had a great run.

One of the keys was having a very open and fluffy, well-drained mix with lots of perlite in it. It prevented the soil from getting water logged when I was flushing the pots. If the soil had been heavy, then I probably would have made the situation even worse by overwatering.
 
rockso15

rockso15

Member
tstick said:
Man, I had this exact problem with my last grow. I'll tell you what fixed it....

I had mixed up my soil(less) mix and thought it was good, but my plants started looking badly deficient at about 3 weeks into veg. I knew the mix had plenty of nutes in it so it couldn't be a deficiency. Then, I decided to do a runoff test just for kicks....WOW! The pH of the runoff water was 4.0! I then did a slurry test and the results confirmed that the pH was waaaaay too low. Okay, so then I knew what the problem was....but how to fix it???

I pH'd my incoming water to ~8.0 and ran several gallons through the pots until I started getting a runoff reading closer to 6.5. After that, I adjusted the incoming water's pH to ~6.0-6.5. After about a couple weeks, the plants rebounded and then I went to a regular feeding schedule of Jack's 3-2-1 and made sure the nutrient-solution was also pH'd accordingly. After that, I had a great run.

One of the keys was having a very open and fluffy, well-drained mix with lots of perlite in it. It prevented the soil from getting water logged when I was flushing the pots. If the soil had been heavy, then I probably would have made the situation even worse by overwatering.
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My veg was ok throughout, these ones are almost done with flowering, but it seems that ph was dropping due to salt buildup little throughout the grow. I can try to rebpund them with flush, heck they need flush anyways cause they are done. I have fluffy soil and 30% perlite it is just that I overwatered some of them and salt build up slowly, even tho I jave fluffy soil and airpots salt will build up no matter, it is roots that hold the salts arpund them, not just soil.

Thanks for the input, will flush tehm 8.0 anyways.
 
amneziaHaze

amneziaHaze

Well-Known Member
rockso15 said:
But my question is I repeat, if my slurry test is 5.5ph what ph should my water be
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hard to tell each soil has different concentrations of minerals that are naturally high ph or low ph and they control the ph of the soil.but as a soil grower bacteria does most of the work soo you should not be worrying about ph.
 
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