Do we need to pH adjust our nutrient solutions?

[Melville Hobbes]

I found something interesting looking up the mechanism behind nitrogen fixation by symbiotic bacteria and legumes.

"All organisms use the ammonia (NH3) form of nitrogen to manufacture amino acids, proteins, nucleic acids, and other nitrogen-containing components necessary for life."
Here's a link to the site I found it on.

 

[Diatomacious]

"Within these nodules, nitrogen fixation is done by the bacteria, and the NH3 they produce is absorbed by the plant."

I'm not in agreement with this report. I don't believe bacteria fix nitrogen in an ammonia form. I'm more certain they would fix nitrogen in a nitrate form. The ammonia comes from decaying matter, the bacteria will consume the ammonia nitrogen nullifying it's toxic effect in the plant.

The ammonia is still a poison whether chemical or organic... chemical is just a lot more than would normally be released by decaying organic matter in a water soluble form (this allows rapid plant uptake). The decaying organic matter also has other food sources for the bacteria than just the nitrogen giving them the chance to digest the ammonia without it being their only food source.

I myself would not have been convinced if I had not been eating organic vegetables from a local farm I know I can trust (the best I can find nutritionally and I've looked) and then consumed a plant grown with ammonium nitrogen. I could tell immediately that this was the major difference between organic and chemical food.

So much food is contaminated with ammonia (even the organics sold in most retail stores) that it is hard to show people the difference. I know of maybe three farms in my area that grow actual organic food (and no they are not certified but stand behind organic principles). Organic food should be grown in actual dirt... soil microbes (the ones we need to eat) don't do well in hydroponic environments.

 

[MightyMoe22]

Don't mean to revive an old thread if this one done. But does or has anyone here used citric acid (used in canning in place of lemon juice) as a replacement for traditional bottled ph down products. Are there any negative side effects that one should be aware of? Or is this a good solution to paying big companies for water and dye?

 

[Diatomacious]

Are there any negative side effects that one should be aware of?

Citric acid will work but if it's an organic grow keep in mind that fruit typically contains lots of ammonia (it's grown with lots of ammonia) and ammonia will kill your microbes.

If it's not an organic grow I would recommend nitric acid. 100% nitrate nitrogen and not poisonous like ammonia.

 

[MightyMoe22]

@Diatomacious thanks for the info. I wouldn't call it a purely organic grow. Maybe closer than some though. In soil, feeding with mega crop and it's bloom supps. What is a good option that's not so hard on the microbes?

 

[Diatomacious]

Mega crop is straight chemical grow. Citric will work but I never had good luck with it (contaminants I suppose). Nitric acid is still my number one choice for your situation. You shouldn't have to pH as the fertilizer will usually bring the pH too low to begin with. I do not pH myself, I let the soil take care of that.

 

[Peat Phreak]

Don't mean to revive an old thread if this one done. But does or has anyone here used citric acid (used in canning in place of lemon juice) as a replacement for traditional bottled ph down products. Are there any negative side effects that one should be aware of? Or is this a good solution to paying big companies for water and dye?

Yes. I use citric acid for pH down. It works fine with peat and salt nutes. It can be used with soil.

Avoid using it for hydroponics or reservoirs.

 

[MightyMoe22]

Gotcha, I was assuming it was organic-ish based solely on their labeling....heh

I really don't have to do much pHing. Generally after adding my nutes to my water it's sitting just a bit over 7. I just make sure I keep it between 6.2 and 6.8.

So nitric acid would be a better option to not kill off any microbes in the soil?

 

[MightyMoe22]

Just did another quick search, apparently gh pH down uses phosphoric acid.

 

[Diatomacious]

I was assuming it was organic-ish based solely on their labeling

Putting organic anything on megacrop is misleading at best. It is totally synthetic nutrients. The ammonia in the megacrop will already have killed off the microbes so no worry there. I like nitric acid because it is 100% nitrate nitrogen with no ammonia. It also only adds nitrogen to your mix whereas phosphoric acid will add more phosphorous... no big deal as long as you take that into account.

 

[Wastei]

Putting organic anything on megacrop is misleading at best. It is totally synthetic nutrients. The ammonia in the megacrop will already have killed off the microbes so no worry there. I like nitric acid because it is 100% nitrate nitrogen with no ammonia. It also only adds nitrogen to your mix whereas phosphoric acid will add more phosphorous... no big deal as long as you take that into account.

Funny you talk about ammonia being poisonous while having Diatomaceous as a username which is high in heavy metals?

Mega Crop is very low in ammonium nitrogen. It's like 1:16 ratio to nitrate? The small amounts of ammonium nitrogen is irrelevant for microbial life in optimal ranges for application.

Microbes use minerals in order to grow, bacteria need a minimum of nutrients: water, a carbon source, a nitrogen source and some mineral salts to complete their cycle.

Mega Crop use mainly Calcium nitrate and Magnesium nitrate for the nitrogen and Cannabis use some small amounts of ammonium nitrate to flourish.

To answer OP question, I've always praised that you should adjust your input according to plant response. That's means you adjust to what they put out in form of leachate. That will tell you the actual pH in the medium. Even better is a pH stick that you can put down in the soil, it make the time and effort less. Bluelabs one is really good.

Microbes are irrelevant in a salt based grow since the nutrients is already in readily available form, you can better spend your time and money on better the chelation and pH stability.

I don't understand why someone would want to add more nitrogen upon a complete plant food?, you will only up the EC and worsen the nutrient ratios? It's better to add small amounts of P with phosphoric acid instead of N with nitric acid, it will affect the mineral ratios less negatively.

 

[Wastei]

What's so funny @bluter? Care to elaborate? Cheers!

 

[bluter]

Funny you talk about ammonia being poisonous while having Diatomaceous as a username which is high in heavy me

Mega Crop is very low in ammonium nitrogen. It's like 1:16 ratio to nitrate? The small amounts of ammonium nitrogen is irrelevant for microbial life in optimal ranges for application.

Microbes use minerals in order to grow, bacteria need a minimum of nutrients: water, a carbon source, a nitrogen source and some mineral salts to complete their cycle.

Mega Crop use mainly Calcium nitrate and Magnesium nitrate for the nitrogen and Cannabis use some small amounts of ammonium nitrate to flourish.

To answer OP question, I've always praised that you should adjust your input according to plant response. That's means what they put out in form of leachate. That will tell you the actual pH in the medium. Even better is a pH stick that you can put down in the soil, it make the time and effort less. Bluelabs one is really good.

Microbes are irrelevant in a salt based grow since the nutrients is already in readily available form, you can better spend your time and money on better the chelation and pH stability.

I don't understand why someone would want to add more nitrogen upon a complete plant food?, you will only up the EC and worsen the nutrient ratios? It's better to add small amounts of P with phosphoric acid instead of N with nitric acid, it will affect the mineral ratios less.

long way to get there but sweet answer.

i run MC. it's better and easier than straight salt based watered out bottle nutes. and @Wastei is right - nothing makes sense in the nute. it runs hot and high in n, but if you feed by a read on the plants, it's all you need straight through flower.

i add some calmag. i run a lot of old led and it still pulls too much out, which can be a hard balance with n heavy nute like MC. i also drop back to make some head room in flower, and run a bit of the booster, but not near what the MC schedule suggests. it's more of a tweak and you don't need it. but picky lol.

edit: my ec is not at all where i would feed on another nute.

 

[Wastei]

long way to get there but sweet answer.

i run MC. it's better and easier than straight salt based watered out bottle nutes. and @Wastei is right - nothing makes sense in the nute. it runs hot and high in n, but if you feed by a read on the plants, it's all you need straight through flower.

i add some calmag. i run a lot of old led and it still pulls too much out, which can be a hard balance with n heavy nute like MC. i also drop back to make some head room in flower, and run a bit of the booster, but not near what the MC schedule suggests.

Your problems are not "Cal-mag" related it's pH stability. Especially if you run the old formula of MC? Cal-mag fix the pH buffer and that's why you see positive results. There's tons of Ca and Mg already in the mix so that's not your problem.

Boosters do very little in sense of increased productivity. I do some foliar sprays in veg but I would never personally spray or add any PK booster shenanigans.

Cannabis needs more or less the same nutrient ratios from start to finish, the different veg and bloom parts is only a result of marketing. NPK of 3-1-4 is optimal for Cannabis according to science.

 

[bluter]

Your problems are not "Cal-mag" related it's pH stability. Especially if you run the old formula of MC. Cal-mag fix the pH buffer and that's why you see positive results. There's tons of Ca and Mg already in the mix so that's not your problem.

i run RO and ph. even though most folk don't bother with ph and wind up with the same result.

i add the calmag as it drops out of usable suspension in the nute. that's a definite weak point on the nute.

running a hoop grow. i'm hempy, so total neutral media.

random gelato

i run about .15 to .20 ec of the calmag.

random acapulco

the total ec with the calmag is not where i'd run other nutes. no claw or tipping. i track ec but i do it all by read.

the stuff is insanely cheap to run. i bought a $120 bag 4 or 5 yrs ago now. i got about 10 - 15 left at this rate.

 

[Wastei]

i run RO and ph. even though most folk don't bother with ph and wind up with the same result.

i add the calmag as it drops out of usable suspension in the nute. that's a definite weak point on the nute.

running a hoop grow. i'm hempy, so total neutral media.

random gelato

i run about .15 to .20 ec of the calmag.

random acapulco

the total ec with the calmag is not where i'd run other nutes. no claw or tipping. i track ec but i do it all by read.

the stuff is insanely cheap to run. i bought a $120 bag 4 or 5 yrs ago now. i got about 10 - 15 left at this rate.

Have you tried replacing it with low dose potassium silicate? I do maybe 2ml "Pro-tekt", 10% solution per 3 gallons of water and that's enough to keep pH stable with RO. My tap is like 50ppm where I'm at so I haven't had to use my RO system in a while. Another good additive to make nutrients more available is Drip Clean, industrially PeKacid. Another even better one to consider is humic acid which helps with chelation, works even better with kelp.

I run the one part (9-7-16) in veg and Calcium nitrate, 5-12-26, Epsom salt in flower with low dose potassium silicate from start to finish. I don't want to add more K than necessary. It usually takes 24h for my solution to stabilize itself and I only have to pH one-two times the first day, then it stays stable.

I would struggle if I didn't use potassium silicate with MC. I did some side by side tests a couple of years ago to check pH stability compared to what I used back then Dyna Gro. Without silicate MC is more or less unusable in my situation. I haven't tried the new formula that's supposed to be more pH stable. From the info I gathered and your pictures I think your problems might be related to water/feeding frequenzy since you need to feed with higher input than you'd like? Do you feed every day to runoff? A couple of times a day would be even better..

 

[Diatomacious]

Funny you talk about ammonia being poisonous while having Diatomaceous as a username which is high in heavy metals?

Mega Crop is very low in ammonium nitrogen. It's like 1:16 ratio to nitrate? The small amounts of ammonium nitrogen is irrelevant for microbial life in optimal ranges for application.

Microbes use minerals in order to grow, bacteria need a minimum of nutrients: water, a carbon source, a nitrogen source and some mineral salts to complete their cycle.

Mega Crop use mainly Calcium nitrate and Magnesium nitrate for the nitrogen and Cannabis use some small amounts of ammonium nitrate to flourish.

To answer OP question, I've always praised that you should adjust your input according to plant response. That's means what they put out in form of leachate. That will tell you the actual pH in the medium. Even better is a pH stick that you can put down in the soil, it make the time and effort less. Bluelabs one is really good.

Microbes are irrelevant in a salt based grow since the nutrients is already in readily available form, you can better spend your time and money on better the chelation and pH stability.

I don't understand why someone would want to add more nitrogen upon a complete plant food?, you will only up the EC and worsen the nutrient ratios? It's better to add small amounts of P with phosphoric acid instead of N with nitric acid, it will affect the mineral ratios less.

What you fail to understand is that chemical fertilizer is contaminated with small amounts of lead, arsenic, mercury, chromium and many other heavy elements that are poisonous to people and animals.

Diatomacious earth is made up of the shells of many diatoms. The only heavy metals in it are what you are dumping down your toilet.

If you take just small amounts of a poison then you are still taking poison. It will give you cancer and organ failure in time. It also makes me uncomfortable with stomach pains, leg cramps, back pain... etc. Not for me!

Personally I would not use Megacrop as it has too many contaminant in it for optimum plant growth.

Microbes are still relevant as they are what convert the ammonia to nitrate making it safe for consumption. This is true for organic or chemical. Why add the ammonia in the first place?

Whether you add nitrogen or phosphorous you are still adding something to your "complete" fertilizer which will add more contaminants. It is not necessary to adjust pH in a soil or soilless grow.

 

[Diatomacious]

chemical fertilizer is contaminated with small amounts of lead, arsenic, mercury, chromium and many other heavy elements that are poisonous to people and animals

This is why you are not allowed to use cheap chemicals in the production of food, drugs or cosmetics. They are poisonous, yet we still grow our food with them.

 

[Wastei]

What you fail to understand is that chemical fertilizer is contaminated with small amounts of lead, arsenic, mercury, chromium and many other heavy elements that are poisonous to people and animals.

Diatomacious earth is made up of the shells of many diatoms. The only heavy metals in it are what you are dumping down your toilet.

If you take just small amounts of a poison then you are still taking poison. It will give you cancer and organ failure in time. It also makes me uncomfortable with stomach pains, leg cramps, back pain... etc. Not for me!

Personally I would not use Megacrop as it has too many contaminant in it for optimum plant growth.

Microbes are still relevant as they are what convert the ammonia to nitrate making it safe for consumption. This is true for organic or chemical. Why add the ammonia in the first place?

Whether you add nitrogen or phosphorous you are still adding something to your "complete" fertilizer which will add more contaminants. It is not necessary to adjust pH in a soil or soilless grow.

I think you got it backwards! It's most often the complete other way around. If you make a fertilizer in a controlled environment and have to stay under strict regulations and standards and fully list all the ingredients and inerts you have complete control of the content.

The only time I've heard of a large scale operation loosing their complete crop from heavy metal testing is from the overuse of DE in a organic grow.

I would never add DE or any rock salt to my vegetable gardens since they all have high heavy metal content. Even kelp has ridiculous amounts of arsenic and I still use it in my gardens. Only the concentration makes the poison. You need to truly educate yourself if you're going to stay safe growing organically. With salts not so much since everything's listed, just follow the recommendations.

Just because an amendment is organic by definition doesn't mean it's clean or safe to use. I think you need to educate yourself more.

 

[Diatomacious]

I think you got it backwards! It's most often the complete other way around. If you make a fertilizer in a controlled environment and have to stay under strict regulations and standards and fully list all the ingredients and inerts you have complete control of the content.

Incorrect

The heavy metal contaminants are already in the mineral when it is mined from the ground. It is why nature always dies around a mining operation... contaminants that were once sealed beneath hundreds of feet of soil are brought to the surface.