Citric Acid

weird. Maybe aquatic bacteria is different then soil? I use earth juice pH down and it's pure 100% citric acid according to the MSDS sheet. Haven't noticed issues.. but then I amend microbes pretty heavily.

magnetik said:

weird. Maybe aquatic bacteria is different then soil? I use earth juice pH down and it's pure 100% citric acid according to the MSDS sheet. Haven't noticed issues.. but then I amend microbes pretty heavily.

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Possibly it's only an issue in aquaponics, the College professor who told me about the issues with Citric acid does run aquaponics, with multiple barrels of fish. They also run separate NFT hydro systems which aren't aquaponics systems, and of course other media types and field crops too.

Rurumo said:

Citric acid won't hurt your bacteria. I've heard that before, but it's just because it's used as a preservative in canning, but it's not the citric acid itself, just the very low PH that you end up with. I used to can tomatoes and I think I used something like 1/2 teaspoon per jar, which makes it extremely acidic. With my water, with Jack's added, I use about 1/2 teaspoon citric acid per 4 gallons to bring ph down to 6. It's much better for a living medium than phosphoric acid just because high levels of phosphorus suppress the microbiome.

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Cool. That's what I thought. I use 1/4 tsp per 4 gal usually, but I've used 1/2 tsp per 4 gals too. Basically 1/16 tsp per gal, but my smallest measuring spoon is 1/8 tsp.

Rurumo said:

Citric acid won't hurt your bacteria. I've heard that before, but it's just because it's used as a preservative in canning, but it's not the citric acid itself, just the very low PH that you end up with. I used to can tomatoes and I think I used something like 1/2 teaspoon per jar, which makes it extremely acidic. With my water, with Jack's added, I use about 1/2 teaspoon citric acid per 4 gallons to bring ph down to 6. It's much better for a living medium than phosphoric acid just because high levels of phosphorus suppress the microbiome.

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PadawanWarrior said:

Cool. That's what I thought. I use 1/4 tsp per 4 gal usually, but I've used 1/2 tsp per 4 gals too. Basically 1/16 tsp per gal, but my smallest measuring spoon is 1/8 tsp.

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The guy who teaches horticulture must be wrong since forum users say so. I'll see him on Friday, and try to remember to bring this topic up, and see if I can get more insights. Admittedly the only info relating to it I can easily find on the internet is in relation to aquaponics.

PJ Diaz said:

The guy who teaches horticulture must be wrong since forum users say so. I'll see him on Friday, and try to remember to bring this topic up, and see if I can get more insights. Admittedly the only info relating to it I can easily find on the internet is in relation to aquaponics.

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I'm genuinely curious. Let us know what he says.

PadawanWarrior said:

I'm genuinely curious. Let us know what he says.

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The science is pretty clear that citric acid is bactericidal, but not equally against all types of bacterium. The same is true of phosphoric acid, but to a lessor degree. My guess is that it has to do with the fact that more citric acid is needed compared to phosphoric acid, in order to achieve the same amount of "ph down", thereby creating an environment which is more toxic for bacteria.

I let my pail sit for a day to let the ph rise a little.Easy to over do it.I used just about a small lines worth in 3 gallons and test drops are orange.After a day it goes yellow greenish.

PJ Diaz said:

The science is pretty clear that citric acid is bactericidal, but not equally against all types of bacterium. The same is true of phosphoric acid, but to a lessor degree. My guess is that it has to do with the fact that more citric acid is needed compared to phosphoric acid, in order to achieve the same amount of "ph down", thereby creating an environment which is more toxic for bacteria.

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Just doesn't make sense to me with the amount I use. I'm curious though.

lakesidegrower said:

I keep debating a soil test, but then I figure that I might just use another mix in the no till pots and start again - incorporate more of what I’ve learned over the past year into the mix and then go to testing.

but who can’t argue with testing - can’t beat it if you want to understand your soil, especially if you run no-till.

i don’t think you necessarily need it to solve an issue you are experiencing,for example. It will likely take longer, require more persistence and perhaps trial and error to arrive at a proper diagnosis and remedy, but the experience in getting there is invaluable. Albeit frustrating lol this is what makes the test so attractive.

also your description of Ca / CaCO3 is pretty much how I understand it as well. The extension of that which I find to be important is that a build up of excess CaCO3 is still a build up a Ca; whether it is in an available form to the plant or not, it will interact with surrounding minerals, and in excess proportions it will cause antagonism of micros and macros (namely K, Mg, and P) , and can also buffer the pH higher in your pots leading to issues with availability in that respect as well.

my take is that you need to account for Ca content in your water and then build your soil accordingly. But you have to account for all of the Ca that’s in there, including any that might be in rock dusts or other organic amendments

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Sorry for another deviation from citric acid, but I believe this info to be important as well...

If you test your soil before planting in it, you avoid any issues that you would have to figure out otherwise. I do agree that it's possible to diagnose issues without a test, but almost impossible to do accurately since many elements work together to produce deficiency/excess conditions.

Also, it's quite difficult to have too much calcium in the soil unless you are using calcium hydroxide as a soil amendment and not giving it time to cook(or watering in another highly available source of ca which is separate from the ca in the soil matrix), and even then it's only too much because it all goes straight into the soil solution and there's way too much available driving the pH up to ridiculous levels. The ideal base saturation of calcium is 85%, magnesium 10-12%, Potassium 3-5%, Sodium 0%. It's impossible to get anywhere close to 85% with the amount of calcium carbonate in water or rock dusts. However, calcium deficiency will most certainly block p uptake, and watering the soil with water high in bicarbonates can create a ca deficiency. The only way to know what's in your water is to have it tested. The risk of running soil pH too high from adding too much calcium carbonate is basically zero unless it isn't allowed to breakdown and become part of the soil matrix. Even with 85% base saturation of calcium, the soil pH will be somewhere around 7.2, and I don't know if it's even possible to get it higher than 85%. I'd be willing to bet that your soil is in the 40% ca base saturation range, so too much calcium isn't the issue.

PadawanWarrior said:

I'm genuinely curious. Let us know what he says.

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He basically told me it's because citric Acid is a relatively weak acid, so you have to use a lot more of it compared to phosphoric acid, which means that it's harsher on the micro herd. He told me that they tried citric acid on their blueberries as a ph down once, and the plants really suffered. As soon as they switched to a different type of ph down, the plants got happy. Blueberries need a pretty low media ph, so maybe it is more pronounced in that situation compared to cannabis media ph, however I'm proceed with caution using citric acid as a ph down.

PJ Diaz said:

He basically told me it's because citric Acid is a relatively weak acid, so you have to use a lot more of it compared to phosphoric acid, which means that it's harsher on the micro herd. He told me that they tried citric acid on their blueberries as a ph down once, and the plants really suffered. As soon as they switched to a different type of ph down, the plants got happy. Blueberries need a pretty low media ph, so maybe it is more pronounced in that situation compared to cannabis media ph, however I'm proceed with caution using citric acid as a ph down.

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I knew it was a weaker acid. And I don't need to add barely any. 1/16 tsp per gal drops it like a point. I'll stick with the citric acid.

He should use elemental sulfur or something if he's trying to lower the soil pH instead of pH down.

Did you know that plant roots generally release citric acid (and also malic acid) when they are hungry for Ca? The citrate mobilises the Ca and after absorption the root will separate & recycle the citrate again

Kassiopeija said:

Did you know that plant roots generally release citric acid (and also malic acid) when they are hungry for Ca? The citrate mobilises the Ca and after absorption the root will separate & recycle the citrate again

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I knew plants released acid, but didn't know it was citric acid. I knew about the citric making Ca more available, breaking it's bond or something like that, but you worded it much better than I could, .

PadawanWarrior said:

I knew plants released acid, but didn't know it was citric acid. I knew about the citric making Ca more available, breaking it's bond or something like that, but you worded it much better than I could, .

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well, it's the books imprinting words in my brain, I don't actually understand the subject
yeah the roots release a lot of stuff, like... list 30-40 or more compounds... even "sugar" to feed microbes and excess nutes for fungi... and ofc, root tissue gets old and breaks down as well... the outer side of the old roots

Brawndo G said:

especially for calcium since it can only be taken in through the root tips.

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??? isn't the tip of the root a slimey mucuous hydrophobic region that should actually repel water?
The Ca should enter the root like the water does

Brawndo G said:

Despite what most people believe about microbes making nutrients available for plants, the plant isn't dependent on them to feed and the roots uptake a crapload of nutrients on their own. The other issue would be that the metals(copper, iron, manganese, zinc, boron) will never be available at 7.2 if you even have them in your soil mix in sufficient quantities to begin with. 6.5 is the upper limit for metal availability and the lower limit for phosphorous availability. I'd pH your water to 6.5, and if it's high in bicarbonates, use a different source of water as bicarbonates will tie up all your calcium carbonate and make it unavailable to the plant.

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just throw citric acid into ur chalky water cooker >> bam bicarbonates gone.

rhizosphere pH can be largely different than soil pH - depending on what the plants crave & excretes/secrets

plants cannot decompose organic macromolecules in soil though they can dissolve minerals from "stone"
just use H2O2 in an organic supersoil grow and chase the deficiency....

Hopefully some will find this useful...

PadawanWarrior said:

Hmmm. I need to do some research. I was under the impression it was fine as long as you don't use too much.

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Thats why citric acid is used as a preservative. Im sure it all depends on dosage but even small amounts would technically wear on and and harm microbial life I would assume.

PJ Diaz said:

The science is pretty clear that citric acid is bactericidal, but not equally against all types of bacterium.

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I'd also like to know what the Prof says about the detrimental citric acid in organic soil.

Actually chemistry is my weakness, but the way I understand acids is they oxidize or catalize a chemical reaction, as long as there are reaction-partners available.
Now if I put citric acid, or any type of acid, in tapwater the acid should react with the water contents until... there is no more acid anymore. It's gone. Or, at least, not acidic anymore

waktoo said:

Hopefully some will find this useful...

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thanks that's been a very good read.
so they say organic acids promote the beneficial bacteria as being food to them, and in turn having better P-availability or nitrite-binding