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soil Acidic soil remedies/solutions and recovery

My plants had been going downhill fast and at first looked to be a potassium def but after thinking about it I realized that the PH was probably low, Soil is just promix with a lil extra pearlite. I water with tap water and hydro nutes which run at a lower PH. I couldn't find my PH probe for the longest time but finally did and was shocked at how acidic the soil was.
 
Here's a few pics of the plants, couldn't tell how discolored they was under the LEDs until I brought them out for their first taste of sun today. 
 

 

 
Here's the readings
 

 
This was a fidalga roxa I potted up the other day, I'm shocked that the PH was so damn low
 

 
This one I may just repot all together with lime mixed in but I was wondering if watering with lime mixed in the water for now on will help buffer the PH back up or if It will be necessary to completly repot them? I think if I get the PH back up they should recover ok. 
 
What water supply do you water them with that is acidic?
 
It shouldnt be your hydro or the plants there would be exhibiting the same thing. So whats your tap water like?
 
CAPCOM said:
What water supply do you water them with that is acidic?
 
The water supply isn't, it's the hydro nutes as hydro is supposed to be more acidic than soil. 
 
juanitos said:
well 5.5 is good for hydro.
 
to fix ph you can add lime and/or wood ashe
 
 
Would adding it to the water be fine, sprinkle ontop soil or repot with it mixed in.. or any of the above work fine?
 
You want to use dolomite lime, not normal garden lime. I believe dolomite works quite a bit quicker then normal lime & dolomite wont take the PH above 7. it will just stabalise it there. Dolomite will also add magnesium and calcium. Normal lime can take PH above 7.
 
I would be surprised if the PH was really that low in store bought potting mix. (unless you purchased an acid mix made for flowers, or added some peat into it)
From my experience, PH usually tends to rise, not fall, (in pots), and especially if watering with normal (hard) tap water. I cant comment on the effect your hydro nutes may be having, but if it does this it may pay to use something thats intended for soil instead
 
I would apply a good amount of dolomite lime and see what happens. Sprinkle it on the top of the soil.
 
D3monic said:
 
The water supply isn't, it's the hydro nutes as hydro is supposed to be more acidic than soil. 
 
 
 
Would adding it to the water be fine, sprinkle ontop soil or repot with it mixed in.. or any of the above work fine?
I wouldn't have known that, I am not doing any hydro yet.
 
K thanks guy, I got two bags of lime laying around here, I will check and see if one's dolomite and their consistency. I think one for sure is more of a granule. 

nzchili said:
You want to use dolomite lime, not normal garden lime. I believe dolomite works quite a bit quicker then normal lime & dolomite wont take the PH above 7. it will just stabalise it there. Dolomite will also add magnesium and calcium. Normal lime can take PH above 7.
 
I would be surprised if the PH was really that low in store bought potting mix. (unless you purchased an acid mix made for flowers, or added some peat into it)
From my experience, PH usually tends to rise, not fall, (in pots), and especially if watering with normal (hard) tap water. I cant comment on the effect your hydro nutes may be having, but if it does this it may pay to use something thats intended for soil instead
 
I would apply a good amount of dolomite lime and see what happens. Sprinkle it on the top of the soil.
 
Promix to my understanding is primarily sphagnum and I believe naturally acidic. I will have to double check the bag. Thanks again. 
 
D3monic said:
K thanks guy, I got two bags of lime laying around here, I will check and see if one's dolomite and their consistency. I think one for sure is more of a granule. 

 
Promix to my understanding is primarily sphagnum and I believe naturally acidic. I will have to double check the bag. Thanks again. 
That will probably be normal, slow acting lime if its granules.
I would suggest you spend a couple of $ and get some dolomite...time is of the essence, the longer you wait the worse off your plants will be.
 
IMO normal lime is more the kind of thing you would apply the previous season to prep your soil for the coming growing season..your plants need what they need now. Not in a few months time.
 
I'd be surprised if your soil in in fact that acidic.  When was the meter last calibrated or its probe cleaned?  My guess is it's light, nutes or over watering possibly.
 
Edit...  Just looked up your tester and thats a horrible way to test soil PH.  Do you have a nursery near you that can test?  if so take a cup to them to check your results.  Should be mixed with DI (or RO) water then tested per the standards set by the EPA. 
 
To check meter accuracy clean the probes by lightly rubbing them with a fine scotchbrite pad, often found as the scrubbing side on a kitchen sponge.  Then check your soil again, my bet is it will change dramatically and still won't be accurate.
 
Nuclieye said:
I'd be surprised if your soil in in fact that acidic.  When was the meter last calibrated or its probe cleaned?  My guess is it's light, nutes or over watering possibly.
 
Edit...  Just looked up your tester and thats a horrible way to test soil PH.  Do you have a nursery near you that can test?  if so take a cup to them to check your results.  Should be mixed with DI (or RO) water then tested per the standards set by the EPA. 
 
To check meter accuracy clean the probes by lightly rubbing them with a fine scotchbrite pad, often found as the scrubbing side on a kitchen sponge.  Then check your soil again, my bet is it will change dramatically and still won't be accurate.
 
I did clean it prior to use as I always do, i've never had an issue with that probe reading low like that. Much more accurate than those cheaper probes though this one can't be calibrated. 
 
I'm with Nuclieye on this one. Also, if you're using Promix, I wouldn't think that you would have any PH issues. It may say, on the bag, that they add dolomite lime to adjust the PH. Just my two cents :-)
 
Understand the nursery thing being that I'm from IN.  I just dug out the first tester I got, cleaned it and check my best looking Chiltepin in my grow room.  The tester is very similar to yours and uses the same principle.  My soil tested 7.8.  I test it constantly on the same tester we use at work on all our regulated effluent that is also tested by the city under our permit.  Just did it again and its still right at 6.4 in fact, thats per the EPA standards.  Just saying to you that the tester you have, or ANY tester that cannot be calibrated can be (often is) very far off.
 
What LED lights do you have?  The plants look pretty good except for the slight discoloration.
 
you need a real ph meter to test soil ph.
 
that thing is not an accurate indication of your soils ph. not even close.
 
promix, from the bail is already ph neutralized. from what i recall, they blend in calcium sulfate and magnesium & calcium carbonate dust( dolomite lime). 
 
those plants look nutrient deficient.
nzchili said:
You want to use dolomite lime, not normal garden lime. I believe dolomite works quite a bit quicker then normal lime & dolomite wont take the PH above 7. it will just stabalise it there. Dolomite will also add magnesium and calcium. Normal lime can take PH above 7.
 
dolomite is a slow lime...if you want very rapid liming you must use a slacked lime(calcium hydroxide) or caustic soda( not reccomended), or potassium hydroxide... etc.
 
the above faster liming agents are fairly dangerous. especially if you are buying the super fine limes intended to make mortars or concrete mixes.  
 
I fert regularly so that's why I assumed low PH not to mention I use my Hydro Nutes that I have on hand. They are probably Nute locked. I will add a little lime to the water every time I fertilize to buffer the PH back up. The lime I had on hand seemed to dissolve in the water fairly well with just a small amount of sludge left in the bottom. 
 
For discussion purposes, and long term acidity reduction (because it takes longer) a good organic method of raising pH is using a ground meal made out of oyster shells in your soil.  balancing pH like this can take longer but remains stable longer in lower pH soils as long as you're not haphazardly adding hot compost to it.
 
queequeg152 said:
you need a real ph meter to test soil ph.
 
that thing is not an accurate indication of your soils ph. not even close.
 
promix, from the bail is already ph neutralized. from what i recall, they blend in calcium sulfate and magnesium & calcium carbonate dust( dolomite lime). 
 
those plants look nutrient deficient.

 
dolomite is a slow lime...if you want very rapid liming you must use a slacked lime(calcium hydroxide) or caustic soda( not reccomended), or potassium hydroxide... etc.
 
the above faster liming agents are fairly dangerous. especially if you are buying the super fine limes intended to make mortars or concrete mixes.  

 
Better than blaming PH for sure, I have starts in a PH over 9 right now that look great.  No soil at all on them.  Light or nute's is the issue I think, PH takes a while and doesn't show like that that I've ever seen.
 
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