View Full Version : The PH battle
luvfriday
03-14-2008, 06:40 AM
I am almost nearing the end of my first grow, last night I couldnā??t sleep thinking do I want to do this again? Well NO, but no one should expect perfection so Ill give it another try.
. . I have battled low PH from day 1. If I set it at 6.5, in 24 hours its under 6.0. Double check by using the meter and the drops it plunges. So I used the entire bottle of PH UP in just over 9 weeks and I opted 3 nights ago to use Baking Soda to raise the PH. Using warm water and baking soda, got a PH at 6.54 and didnā??t touch it as I predicted it would be 6.0 next time I check.
Yesterday I carry out the same routine as usual, but for the first time ever my PH has gone up to nearly 7. Yeah I had to triple check to make sure, but for the first time ever my PH went up?
I think the baking soda is the obvious cause, and I think as water evaporated it became stronger.
One more question, I got neem oil to tame some powdery mildew itā??s the oil extract but how often do I spray the plants with it?
darbolah
03-14-2008, 06:58 AM
im also a soldier on the front line in the war against unstable pH levels. Dont stop growing tho, imo you can still get a good yeild without trying to hard. I saw a thread where someone grew 1 plant in crap soil with no nutes and no pH bal and he got almost 1 oz from just that plant which is good considering he used 1 cfl and the plant was no bigger than 10-12" tall. Just keen trying :)
stinkyattic
03-14-2008, 01:40 PM
Start with a composted humus based soil rather than peat based. The pH is much more stable over time, as the humic acids act as a buffer.
I have a question; how long did you let any given plant remain in the same pot without re-potting?
Weedhound
03-14-2008, 02:14 PM
I think luv is growing hydro......Luv....you've hit the reason the many hydro growers switch to RO and/or distilled water. It REALLY HELPS keep your ph under control and you also know exactly what and how much minerals etc your plants are getting in your hydro conditions. But the ph thing alone is worth it imo. ;)
Rusty Trichome
03-14-2008, 02:32 PM
luvfriday: A whole bottle of ph up in a couple of weeks? I've got the opposite problem. My well water comes out at around 8.1, but I use GH's ph down. (phosphoric acid) I got a gallon a couple of years ago, and still have 1/2 gallon left, and use it for my houseplants, too.
When was the last time you calibrated or checked the accuracy of your meter?
imo you can still get a good yeild without trying to hard. I saw a thread where someone grew 1 plant in crap soil with no nutes and no pH bal and he got almost 1 oz from just that plant which is good considering he used 1 cfl and the plant was no bigger than 10-12" tall. Just keen trying :)
Any chance of getting that link from ya? I'd love to find out how to do a half-assed job, with inadequate lighting and no nutes, yet still have a smokable result. How was your next grow?
grey1223
03-14-2008, 08:03 PM
1/2 liter of PH down lasts about as long as a gal. of PH up for me. I also notice that it takes much more PH up to raise ph than it does PH down to lower it. The instructions state that 1 teaspoon of PH down or PH up will move your PH the same amount. I don't find that to be true.
stinkyattic
03-14-2008, 08:12 PM
1/2 liter of PH down lasts about as long as a gal. of PH up for me. I also notice that it takes much more PH up to raise ph than it does PH down to lower it. .
Yeah and this is because pH up is (I believe) Potassium hydroxide, KOH, and pH down is Phosphoric acid, H3PO4- a tri-protic acid, and VERY strong.
The active components in each are the -OH group and the -H respectively.
Mr. Brown
03-14-2008, 08:14 PM
whats the verdict on baking soda to raise Ph? Does anybody know if it causes any lockout after awhile.
stinkyattic
03-14-2008, 08:19 PM
whats the verdict on baking soda to raise Ph? Does anybody know if it causes any lockout after awhile.Yup. Sodium bicarbonate.
It's a weak base, not a strong base, and does not include the desirable -OH group, so you have to use a lot to get the same effect, plus it has a buffering range of its own. The active group in baking soda is a carbonate ion, CO3, the same as in lime, but lime contains Calcium as the positive ion, rather than Sodium, which at more than trace levels is detrimental to plant health.
You're safer with lime, but FAR better off with KOH.
Weedhound
03-14-2008, 08:46 PM
Yup. Sodium bicarbonate.
It's a weak base, not a strong base, and does not include the desirable -OH group, so you have to use a lot to get the same effect, plus it has a buffering range of its own. The active group in baking soda is a carbonate ion, CO3, the same as in lime, but lime contains Calcium as the positive ion, rather than Sodium, which at more than trace levels is detrimental to plant health.
You're safer with lime, but FAR better off with KOH.
so PHHHHHHHHHHHHHH! :D
luvfriday
03-15-2008, 02:23 AM
In case I havent said it enough.....THANKS TO EVERYONE!! I would have been lost without your help.
Yeah and this is because pH up is (I believe) Potassium hydroxide, KOH, and pH down is Phosphoric acid, H3PO4- a tri-protic acid, and VERY strong.
The active components in each are the -OH group and the -H respectively. If PH down is strong, then I got real big problems.
1/2 liter of PH down lasts about as long as a gal. of PH up for me. I also notice that it takes much more PH up to raise ph than it does PH down to lower it. The instructions state that 1 teaspoon of PH down or PH up will move your PH the same amount. I don't find that to be true.
Yes I agree I did raise it too high once, and found 1 drop of down was much stronger then the PH up.
luvfriday: A whole bottle of ph up in a couple of weeks? I've got the opposite problem. My well water comes out at around 8.1, but I use GH's ph down. (phosphoric acid) I got a gallon a couple of years ago, and still have 1/2 gallon left, and use it for my houseplants, too.
When was the last time you calibrated or checked the accuracy of your meter?
I have about 6 Hanna Calibrated soulotions here but none are the ones I need to check MS (ppt), however the PH is calibrated and I still sometimes double check with the PH drops to be sure. [QUOTE]
[quote=Weedhound]I think luv is growing hydro......Luv....you've hit the reason the many hydro growers switch to RO and/or distilled water. It REALLY HELPS keep your ph under control and you also know exactly what and how much minerals etc your plants are getting in your hydro conditions. But the ph thing alone is worth it imo. ;) I have a Like New distiller Ill sell cheap. My PH was dropping to the 4s when I was using distilled and r/o, because I came across some people saying tap water wasnt so bad I tried it and its made PH a little better because when it 4s you told me to get my act together and figure out why........now I have a book where I write this crap down. I started mixing all the water into 1 container, getting PH ideal then filling the hydro buckets back up with 2 gallons each. Next day I can test PH and its never the same so drain both set PH again and so on .
im also a soldier on the front line in the war against unstable pH levels. Dont stop growing tho, imo you can still get a good yeild without trying to hard. I saw a thread where someone grew 1 plant in crap soil with no nutes and no pH bal and he got almost 1 oz from just that plant which is good considering he used 1 cfl and the plant was no bigger than 10-12" tall. Just keen trying :) An ounce!!! I was hoping that was hoping for a pound at least...........I better issue a revised forecast of an ounce to a half pound. Trying hard, I practically put them in a stroller and take them for walks everyday. Ill try less, if I can.
Weedhound
03-15-2008, 02:37 AM
Ok....lets start from the beginning....aren't you thrilled? I remember you saying it was jumping all over .......
Can you do your specs for me including ppm? Medium...hydroton? Is it dropping or raising....and is pretty much the same trend (always lower? or always higher?)
Ph consistently dropping usually means some sort of roots rotting or dying......ph consistently too high could be nute burn or even normal depending on where the plant is in flowering (late flowering plant's ph can rise about 1 point a day around my house....)
Give me all the info you can.
Weedhound
03-15-2008, 02:40 AM
luv....have you done a system flush on your plants.....that may be next up after their next trip to the playground.....:D
luvfriday
03-16-2008, 07:35 AM
I did a flush for the first time about 2 weeks ago, let the system run like an hour before adding nutes.
2 buckets, 2 gallons water each, hydroton, water for 15 minutes every hour, cut water way back when lights are off. Temps are between 70-85 had powdery mildew and just got it under control.
Last 3 weeks PH drops from over 6.0 to mid 5 in 24 hours. Last 4 days since using baking soda to up PH. Problems going high for 2 days, now for 2 days PH has not moved from 6.3 and I double check it.
PPM can go up but never in both buckets just 1.
Weedhound
03-16-2008, 06:51 PM
Luv is there a reason you are only watering 15/45? I run my drip stuff 24/7. I wonder if doing that is drying out some roots and that's why you are losing them (if you ARE losing them.....but it sounds like it with a continually dropping ph). You might try running the drips 24/7 for awhile and see it makes a difference.
Weedhound
03-16-2008, 06:53 PM
Also...next time you flush....don't put the same water you are flushing with back in the system (maybe i'm mistaken but that sounds like what you did.......:confused:) Change the flushed water out for new solution w/nutes. ;)
luvfriday
03-16-2008, 09:34 PM
Also...next time you flush....don't put the same water you are flushing with back in the system (maybe i'm mistaken but that sounds like what you did.......:confused:) Change the flushed water out for new solution w/nutes. ;)
I should have been more specific, I changed the water after the flush. Here is the GH instructions that say to run on a timer like I have been. I dont remember where I got the idea weeds werent water loving plants but I guess its a possibility.
Weedhound
03-16-2008, 09:42 PM
All I know is I run mine 24/7 and was told to by my hydro guy which I take as close to gospel as the bible. ;)
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