Acid flushing at 3.0 pH to reduce media pH works

[Peat_Phreak]

The pH of the media was 7.8 after 4 weeks of veg. I was able to reduce it to 5.7-6.4pH and keep it in the safe zone. How?

By using a shit ton of citric acid and water. pH the water to 3.0. This takes about 15g-20g of citric acid per gallon with average tap water. The first flush was a big one. 10 gallons per plant. This isn't something that can be cured with one flush. I had to repeat it before feeding for about 3-4 weeks before it became fairly stable in the low to mid 6's.

The subsequent flushes did not need 10 gallons. They got just enough volume to get runoff with 3.0 pH citric solution. Then feed with a bicarbonate free nute mix 15 minutes later. It took about a week to get out of the pH danger zone.

After it got down to the low sixes, I didn't need to hit it with acid before each feed. It's only once per week now. Grow has about a month to go. But it's not too early to call this acid flush thing a success.

I did this on four different strains. All the plants are doing fine. No leaf issues after I got the pH in check.
So if you try ever this and it doesn't work, well you clearly did it wrong! This would be harder to do near the end of the grow because more bicarbonate has accumulated compared to my 4 week old example. It's worth a try if you ever have high media pH issues.

 

[JeanMichel]

what medium do you speak of ?

you don't have to periodically flush your media, a large drain each feed is enough
also monitoring your runoff ph is misleading

as long as you give enough nutrients, ph 5.5 with a large runoff you will not have issues

ph naturally climb in the medium as plants veg
perfectly normal

never flush plants heavily, especially at ph 3;0

If you have hard water (rich in calcium bicarbonate) use some nitric acid
also it gives a plant a boost in calcium byt conveting the calcium bicarb in calcium nitrate

 

[Peat_Phreak]

what medium do you speak of ?

peat, perlite, dolomite, silicate. SS#4 mix.

you don't have to periodically flush your media, a large drain each feed is enough
also monitoring your runoff ph is misleading

Re-read the OP. pH of the media was 7.8 after 4 weeks of veg. Experience tells me that leaf issues start to occur at 7.8 and above with my system. I always get plenty of runoff. Monitoring pH is not misleading if you know how to read it. It's necessary if you actually want to control the media pH. The ideal pH range for optimal nutrient absorption is a lot lower than 7.8.

ph naturally climb in the medium as plants veg
perfectly normal

Nutrient lockout is often a consequence of high media pH. And by managing media pH, we can create conditions where the pH remains in the optimal zone. There are a few ways to do that. Acid flushing is one of them.

as long as you give enough nutrients, ph 5.5 with a large runoff you will not have issues

This is not universally true. Bicarbonate content matters more than the input pH in terms of managing media pH. I can feed at 5.5 pH with 25% runoff and get high media pH. There is plenty of bicarbonate left over in the tap water at 5.5 pH. That will raise the media pH with every watering. The plant excretes bicarbonate or hydroxide after every feeding. That will raise the media pH. The only way to reduce it is with acid. That acid can come from microbes, nutrients or treated water.

never flush plants heavily, especially at ph 3;0

Oh really? I've been doing it long enough and frequently enough to see that is works. Nothing bad happened to the plants. The media pH was reduced from 7.8 pH to an average of 6. Mission accomplished.

If you have hard water (rich in calcium bicarbonate) use some nitric acid
also it gives a plant a boost in calcium byt conveting the calcium bicarb in calcium nitrate

Ok buddy. Now tell me how much nitric acid I need to use to neutralize the bicarbonate in my water and what the pH will be. Then tell me how much nitric acid I need to use to neutralize the bicarbonate built up in the media and what the pH of that solution will be. Then tell me how much acid I need to neutralize the bases the plant produces with each feeding. Then tell me how much N we added to the media while chasing your questionable advice.

Spoiler alert - it's gonna be too much N. That is one of the many reasons why citric acid is the best choice for this type of heavy handed acid drenching fuckery! It does not have NPK. It's a chelator and a biostimulant.

 

[Peat_Phreak]

And for my next bro science experiment, I will be using my good friends Lactobacillus Plantarum to hopefully provide a constant, but gentle source of lactic acid directly in the media 24/7. If that fails, I can always use it for inner bowel support or to make some super delicious sour beer.

And this is not just any lactobacillus. This particular strain works well at room temperature while most others need to get up to 100F to crank out enough acid. I've also been told this won't work by people that haven't tried it. This makes me want to try it more. I am absolutely certain this can make acid, but I have no idea if it will work well enough to make a difference.

 

[Peat_Phreak]

Some quick research says this is not insane. Using lacto with plants is a thing. It produces other useful compounds besides acid. It stimulated growth in wheat in soil and hydro. So even if it doesn't do much for pH, it can still be useful.

EFFECT OF LACTOBACILLUS PLANTARUM ON GROWTH CHARACTERISTICS OF WHEAT IN HYDROPONICS AND SOIL – DOAJ

The aim was to study the effect of Lactobacillus plantarum on germination and some growth characteristics of wheat Triticum aestivum L. in hydroponics and...

doaj.org

EFFECT OF LACTOBACILLUS PLANTARUM ON GROWTH CHARACTERISTICS OF WHEAT IN HYDROPONICS AND SOIL​

 

[JeanMichel]

all this is intellectual masturbation

so you basically grow in soil. i dont understand if you grow organic, or a mix of organic with mineral feed?

you do not need all these snake oils

because you do bad practice for long times do not prove its good
you will never see pro growers or greenhouse operators feed at pH 3,0
in fact PC drippers do not even resist this pH

if your veg nutrition is well balanced your ph should not climb so much
and i repeat myself, if you have hard water use nitric acid

my water measure 1,2 mS out the tap
most growers would tell you its the worst water to grow with

thats because they use phosphoric acid
never use phos. acid with hard water

first phosphates will precipitate, and moreover you wont benefit the extra calcium and magnesium contained naturally in your tap water

only nitric acid convert the bicarbonates to nitrates

so if you have high bicarb water ====> nitric acid


if you do not listen to good advices i can't do anything for you

also i never understood the goal to grow in soil with mineral nutrients ? you would get 2x better results in coco or rockwool

bother with soil only if you grow 100x organic with your own compost ... which is still a non sense indoor for many reasons

indoor==>rockwool coco

thats my 2 cents

 

[Peat_Phreak]

so you basically grow in soil. i dont understand if you grow organic, or a mix of organic with mineral feed?

Peat is NOT basically soil. It is commonly known as soil-less media. Nutes are salts plus some organic extras.

you do not need all these snake oils

Acid is not a snake oil. It is a substance that is commonly used to control pH.

If your veg nutrition is well balanced your ph should not climb so much
and i repeat myself, if you have hard water use nitric acid

Define well balanced nutes.

Hard water can be neutralized with almost any acid. I noticed you completely avoided the issue of using excess N and have no idea how much N it would contribute in this scenario. Citric acid neutralizes the bicarbonate in tap water and has no NPK. There is zero advantage to using nitric acid for this.

if you do not listen to good advices i can't do anything for you

I wasn't asking for advice and you haven't given any good advice here. I already solved my own problem and I'm just sharing information.

also i never understood the goal to grow in soil with mineral nutrients ? you would get 2x better results in coco or rockwool

Maybe that is because you don't understand that peat isn't soil and it works very well with salts.

you will never see pro growers or greenhouse operators feed at pH 3,0

It doesn't matter what so called pros do. If it works, it works. And it worked.

 

[Cophiljay]

Troll much?

 

[JeanMichel]

20 grams of citric acid per gal
sweet jesus

you are on the wrong track

all you do by flushing heavily your roots is stressing the plants

plants are living beings, they like stability

as i said, DO NOT watch the ph of your runoff, just feed at the right ph (around ph 6 for peat), with some runoff, and OBSERVE the plants

 

[Peat_Phreak]

20 grams of citric acid per gal
sweet jesus

you are on the wrong track

I actually used 15g per gallon. I was giving a range for average tap water in the USA. How could I be on the wrong track if the mission was accomplished? I could have used less acid and it would not have worked as quickly or as well. Been there. Done that. The 3.0 pH is how big moves can be made. It still takes time and repetition.

all you do by flushing heavily your roots is stressing the plants

Hey dude. Not sure if you realize this, but I can actually see how my plants reacted. They loved every minute of it. It saved them from a manganese deficiency that was starting and was due to high media pH that I corrected.

as i said, DO NOT watch the ph of your runoff, just feed at the right ph (around ph 6 for peat), with some runoff, and OBSERVE the plants

That will result in high media pH and less than optimal nutrient absorption. However, the plants will grow and a harvest will happen. Possibly with some bad leafs along the way. I can use 4.0pH-4.5pH while feeding for the entire grow. That keeps the media pH out of the danger zone which is 7.8 pH and up.

The main reason my pH got so high in veg this time is because I didn't pH the feed at all in the beginning. That was done on purpose for this experiment.

I monitor the runoff pH, the media pH and the feed pH. All of them provide useful information to me.

 

[Peat_Phreak]

Troll much?

No. This is 100% serious business. It's a radical approach to pH management that seemed like it would work and it did. This is a trailblazing moment !!!

Now, if people try this and don't get similar results or get bad results, I don't know what to say other than it really did work for me and our variables were probably not identical. I have been doing this in various forms for a while and will continue to use the heavy duty citric acid flush as needed.

I am looking forward to trying the lactobacillus thing too. That's not trolling either.

 

[JeanMichel]

elucubrations.

 

[JeanMichel]

A lot you still have to learn son.

 

[Peat_Phreak]

A lot you still have to learn son.

You have had plenty of opportunity to school me. It hasn't happened. That is because you don't have anything to teach. I'm willing to listen.

 

[RootsRuler]

There are infinite possibilities to how to handle certain issues. Even if it defies common knowledge or empirical science if it works for you then great.

@JeanMichel - If you have any empirical scientific evidence to back up your claims please post it. I'm interested in reading why runoff measurements have no worth.

@ PeatPhreak - I've run into your issue but at the opposite spectrum when growing in Coco Coir. My runoff and soil PH's always seemed to drop to around 4.8. In that setup I had RO water as my base that was PH'ing at around 8.5 or 9. With the addition of nutes it would test at around 7. I'd water at this PH level and test runoff that was testing at 5.8 - 6.0. I agree that your method is valid through my own experience although the addition of acid at those PH levels makes me nervous. I know you said you had no issues. I just wonder if you had any stunting due to shocking the roots with such an acidic solution.

 

[Peat_Phreak]

@ PeatPhreak - I've run into your issue but at the opposite spectrum when growing in Coco Coir. My runoff and soil PH's always seemed to drop to around 4.8. In that setup I had RO water as my base that was PH'ing at around 8.5 or 9. With the addition of nutes it would test at around 7. I'd water at this PH level and test runoff that was testing at 5.8 - 6.0. I agree that your method is valid through my own experience although the addition of acid at those PH levels makes me nervous. I know you said you had no issues. I just wonder if you had any stunting due to shocking the roots with such an acidic solution.

Your low pH situation is likely due to the following potential issues:

- too much ammonium and not enough nitrate in the nute mix.
- bacterial acidification
- not enough lime in the media
- combination of the above

It sounds like you used potassium silicate in your feed to get the pH up? That is what I would do in that situation, but I've never had low media pH. What you and I are doing works because the plant drinks fluid that has mixed with the media. When the fluid mixes with the media, its pH changes instantly.

So your plant isn't drinking 9.0pH when you feed it thru 4.8 pH media. It's drinking the combination of the the liquid and the media. If it was drinking 9.0pH it would be a disaster. What it is actually drinking is closer to the runoff. In your case, the runoff was right where it should be and I'll bet your plants grew well.

Conversely, my plant isn't drinking 3.0 pH when I feed it thru 7.8 pH media. The 3.0 pH instantly gets lowered into something a lot less scary. Like 6.4 pH, etc. It neutralizes a lot of bicarbonate in the process. The entire point of dumping this much acid is to neutralize bicarbonate that has built up in the media. This will lower the media pH over time with repeated treatments. Eventually, the acid can dominate the media. If that happens, use less acid. I got it down to the point where I only hit it with acid once a week and use less acid. One plant got all the way down to 5.1 pH from 7.8 pH. That took a month.

Since my feed is nitrate dominant, the pH of the media will rise after every feeding unless I supply enough acid to correct it. If I simply acidify my feed to 5.8pH, that will cause the media pH to rise because bicarbonate is present at 5.8 pH. To completely remove bicarbonate from tap water with acid, the pH needs to be around 4.0 with my average tap water.

This 4.0 pH acid solution has very little 'acid power' left over to neutralize bicarbonate in the media. But it has enough power to reduce the media pH a little. Like by 0.2-0.4 pH over a couple weeks. Big moves require more acid. That's how I got down to using 3.0 pH of citric acid.

 

[RootsRuler]

I would think that regardless of the alkaline soil composition the raw acid that goes into contact with roots is what makes me nervous but if it's been working for you with no ill effects then continue.

 

[Peat_Phreak]

I just wonder if you had any stunting due to shocking the roots with such an acidic solution

Forgot to address this in my last comment. I have not noticed any stunting or anything bad at all. This run is currently in different stages of bloom with four different strains. The plants aren't huge trees, but it looks like the yield will be good.

 

[Peat_Phreak]

I would think that regardless of the alkaline soil composition the raw acid that goes into contact with roots is what makes me nervous but if it's been working for you with no ill effects then continue.

In nature, there are massive colonies of acid producing microbes that are in direct contact with the roots. They crank out undiluted acid 24/7. The pH of the acid is lower than 3. The acid is kept in check by the media and plant's alkaline exudates.

I have seen scientific papers where they are using a lot more acid than me and they are using stronger acids like sulfuric. They are able to drop the pH by 3 points with one super hot dose of sulfuric acid. That sounded too risky for me. So I did this.

 

[RootsRuler]

In nature, there are massive colonies of acid producing microbes that are in direct contact with the roots. They crank out undiluted acid 24/7. The pH of the acid is lower than 3. The acid is kept in check by the media and plant's alkaline exudates.

I have seen scientific papers where they are using a lot more acid than me and they are using stronger acids like sulfuric. They are able to drop the pH by 3 points with one super hot dose of sulfuric acid. That sounded too risky for me. So I did this.

Hmmmm....interesting....if you have any links to the studies I'd love to read them!!