Thanks man I mighr try that further down the line im only couple weeks in.
Do we need to pH adjust our nutrient solutions?
- Thread starter InTheShed
- Start date
Diatomacious
Well-Known Member
It really doesn't mean much in my experience. USDA or OMRI are just a $7000 payout to the government. The USDA police do not stand over the farmers shoulder when he fertilizes his field. I would still check with the wet test... if you don't feel pain or a burning sensation then that fertilizer is uncontaminated.
You should ask Dr Bugbee then.
Diatomacious
Well-Known Member
Definitely check your fertilizer with the wet test I mentioned. Adding ANY AMMONIA AT ALL to the grow and you will end up killing off the microbes instead of helping them as well as poisoning your crop with ammonia. It takes months if not years for the microscopic organisms to neutralize the ammonia from chemical input.
Good luck
Thanks for the info. CL
Diatomacious
Well-Known Member
Glad to help. This affects everyone on the entire planet so feel free to share with everyone.Thanks for the info. CL
- Thread starter
- #526
The actual instructions for pH testing your medium using either the pour-through or slurry method are posted here. There are very simple yet specific instructions that need to be followed so you get the actual answer you need to sort out what might be the next step.
Hi shed hope your all good man. Thanks for the link al have a look
Chuckeye
Well-Known Member
How to Maintain the Proper pH of a Growing Medium | PRO-MIX Greenhouse Growing
When asked “How do you maintain the proper pH of a growing medium?”, often the answer is to adjust the water pH to achieve a growing medium pH in the ideal range of 5.6-6.2. This is simply not true.
www.pthorticulture.com
Cheers
Mountainman80
Well-Known Member
But if I a just pH in the water I'm giving. My plants do I nerd to worry about th.pH in the soil because I'm putting pH water of 6.7 into my soilGreetings all! I recently had a running email conversation with the "Grower Services & Product Development Director" at ProMix (aka Premier Tech). I began the conversation by posting a question on their website, asking if I should be treating ProMix HP as soil or soil-less when mixing nutrients.
[Please note that we were not discussing hydro growing. This conversation does not apply to hydro.]
As we have all been taught, the pH range for nutrients is different for soil and soil-less media and I had been using the soil range in my ProMix and wanted to double check. His response left me confused, as he answered the question by giving me the ideal pH range for mineral soil and soil-less growing media. He did not address my question of the correct pH of the nutrient mix.
We went back and forth for a few days and his answers always referred to the pH of the media and not what we were pouring into the media. I kept trying to narrow my question and he continued in the same vein. I contained my exasperation so as not to short circuit the chain.
At one point he said this:
"It is the potential acidity or basicity of the fertilizer chemistry and the alkalinity content of your water that affects the pH of the growing medium. For the fertilizers, it is called ‘potential’ since it is determined by the chemistry and the quantity of fertilizer nutrients that are applied and the ‘potential’ they have to interact with the plant root system and influence the pH of the growing medium up or down."
All related to the medium. And the interesting use of the word "potential," but again ended it by talking about moving the pH of the growing medium.
Rather than bore you with the all back and forth, I will post this summary that I sent him in one of our last emails. He approved of this summary (italics mine):
1. Ideal pH range for mineral soil is 6.0-6.5. Soil-less growing media, such as PRO-MIX, have an ideal pH range of 5.5-6.0.
2. However, pH of nutrient water is irrelevant to the pH of any soil or growing media. It is the alkalinity of nutrient water and the potential acidity/basicity of the fertilizer(s) that influence the pH of the growing medium and root zone. For example, if the alkalinity of nutrient water is moderate or high, pH of growing medium will rise over time.
a. Plant roots are electrically charged and must maintain a neutral balance.b. For ammonium nitrogen (NH4) fertilizers, plants release of hydrogen ions to take up NH4. Hydrogen released is essentially acid and this drives pH down.c. For nitrate (NO3) form of nitrogen in fertilizers, plant exchange hydroxyl ions for NO3 uptake, which causes growing medium pH to rise.d. Alkalinity (CACO3) is essentially dissolved limestone. The higher the alkalinity of water, the greater tendency to raise pH of growing medium over time.
3. It is more important to keep track of the pH of the growing medium than the pH of the nutrient solution we feed the plants.
And at the bottom of that summary I added one last direct question:
"If I’m growing in ProMix HP and I mix up the nutrient solution and it reads 7.4 pH, it is not necessary for me to adjust that number down using phosphoric acid or the like. I can pour it into the pot at 7.4 and my plants will be able to uptake those nutrients?"
His response was a direct "Yes."
-----------------------------------
We had discussions on the correct way to check the pH of soil or soil-less medium (none involved checking our nute runoff). I'll post the various methods he sent me in a different thread and post a link here. I don't want to distract from the info above!
- Thread starter
- #531
Thanks for the heads-up Flatfish!
Thanks Chuckeye!
Soil has excellent buffering ability and can tolerate highly alkaline water as well as high nitrate fertilizer a lot longer in a grow than ProMix, but setting your water pH to 6.7 won't do you any harm. That doesn't mean soil's can't shift over time as well.
If you run your plants a long time in the same soil or reuse it, it's not a bad idea to run a slurry test on the soil before the next grow, especially if you know your water is high in alkaline content.
Mountainman80
Well-Known Member
Thank you greatly appreciated
JoetheChro
Well-Known Member
Greetings all! I recently had a running email conversation with the "Grower Services & Product Development Director" at ProMix (aka Premier Tech). I began the conversation by posting a question on their website, asking if I should be treating ProMix HP as soil or soil-less when mixing nutrients.
[Please note that we were not discussing hydro growing. This conversation does not apply to hydro.]
As we have all been taught, the pH range for nutrients is different for soil and soil-less media and I had been using the soil range in my ProMix and wanted to double check. His response left me confused, as he answered the question by giving me the ideal pH range for mineral soil and soil-less growing media. He did not address my question of the correct pH of the nutrient mix.
We went back and forth for a few days and his answers always referred to the pH of the media and not what we were pouring into the media. I kept trying to narrow my question and he continued in the same vein. I contained my exasperation so as not to short circuit the chain.
At one point he said this:
"It is the potential acidity or basicity of the fertilizer chemistry and the alkalinity content of your water that affects the pH of the growing medium. For the fertilizers, it is called ‘potential’ since it is determined by the chemistry and the quantity of fertilizer nutrients that are applied and the ‘potential’ they have to interact with the plant root system and influence the pH of the growing medium up or down."
All related to the medium. And the interesting use of the word "potential," but again ended it by talking about moving the pH of the growing medium.
Rather than bore you with the all back and forth, I will post this summary that I sent him in one of our last emails. He approved of this summary (italics mine):
1. Ideal pH range for mineral soil is 6.0-6.5. Soil-less growing media, such as PRO-MIX, have an ideal pH range of 5.5-6.0.
2. However, pH of nutrient water is irrelevant to the pH of any soil or growing media. It is the alkalinity of nutrient water and the potential acidity/basicity of the fertilizer(s) that influence the pH of the growing medium and root zone. For example, if the alkalinity of nutrient water is moderate or high, pH of growing medium will rise over time.
a. Plant roots are electrically charged and must maintain a neutral balance.b. For ammonium nitrogen (NH4) fertilizers, plants release of hydrogen ions to take up NH4. Hydrogen released is essentially acid and this drives pH down.c. For nitrate (NO3) form of nitrogen in fertilizers, plant exchange hydroxyl ions for NO3 uptake, which causes growing medium pH to rise.d. Alkalinity (CACO3) is essentially dissolved limestone. The higher the alkalinity of water, the greater tendency to raise pH of growing medium over time.
3. It is more important to keep track of the pH of the growing medium than the pH of the nutrient solution we feed the plants.
And at the bottom of that summary I added one last direct question:
"If I’m growing in ProMix HP and I mix up the nutrient solution and it reads 7.4 pH, it is not necessary for me to adjust that number down using phosphoric acid or the like. I can pour it into the pot at 7.4 and my plants will be able to uptake those nutrients?"
His response was a direct "Yes."
-----------------------------------
We had discussions on the correct way to check the pH of soil or soil-less medium (none involved checking our nute runoff
Chuckeye
Well-Known Member
Well water ppm is ~500 and ph is ~7.5. Varies a bit over the seasons.
ProMix HP, 3 gallon fabric bags, 600w MH/HPS, MC nutrients.
NO Ph down....
Day 100, 50 of flower, Double Chocolate photoperiod.
Cheers, eh ?
ProMix HP, 3 gallon fabric bags, 600w MH/HPS, MC nutrients.
NO Ph down....
Day 100, 50 of flower, Double Chocolate photoperiod.
Cheers, eh ?
KeithLemon
Well-Known Member
That would make a nice wall picture.Well water ppm is ~500 and ph is ~7.5. Varies a bit over the seasons.
ProMix HP, 3 gallon fabric bags, 600w MH/HPS, MC nutrients.
NO Ph down....
Day 100, 50 of flower, Double Chocolate photoperiod.
Cheers, eh ?
Chuckeye
Well-Known Member
Peat Phreak
Well-Known Member
A little update on this. I did a bro science experiment that concluded with very predictable results.
Against my better judgement, I listed to InTheShed and ditched my reliable pH down routine and incorporated the maximum amount of ammonium that I am willing to use. Because according to InTheShed, this is "how the pros do it". Despite only 4% of pros actually doing it that way.
That regimen resulted in a peat media pH of 7.8 by the 4th week of veg. The ammonium didn't control the pH of the media. Experience tells me that this is where leaf issues start to occur with my system, so I entered my proprietary citric acid flush mode which is NOT even supposed to work at all according to a mod at THC Farter.
So it turns out, I was able to drop a 5 gallon bucket of 7.8 pH peat down to 6.4 pH with only 10 gallons of my proprietary citric acid flush. I also had some mature seedlings in 1 gallon pots that were already up to 7.3 pH. They were easier to fix than the big buckets in veg. They required much less citric acid flushing at a lower acid concentration and higher pH.
The key to a successful citric acid flush is to think more in terms of grams of acid rather than pH. First, we need to use enough acid to completely remove ALL the bicarbonate from the water. If the result is 4.3 pH when zero bicarbonate occurs, that water has almost zero ability to reduce the ph of the media. So we need to add even more acid to produce a negative residual alkalinity for the flushing agent. How much acid to add after zero bicarbonate is achieved depends on how much bicarbonate and carbonate we need to neutralize in the media.
I used 15 grams of citric acid per gallon of tap water. That's a lot. My bicarbonate is about 75 ppm before acid. This dropped the pH of my proprietary citric acid flush down to 3.2. If your water bicarbonate is higher than mine, you would need to use more acid to get down to 3.2 pH. My runoff dropped from 1400ppm to 480ppm.
I didn't need to get so extreme with the mature seedlings. They only needed a flush with 4.0 pH citric acid. I have also previously used this less extreme version of acid flushing to reduce 5 gallons of alkaline media by smaller amounts such as dropping the pH by 0.2-0.5 with similar amounts of flushing.
So now that I have that bro science experiment under my belt, I shall return to acidifying my feed which removes or reduces bicarbonate from the tap water. This results in a lower media pH over time. It's the main reason to acidify tap water. I have done entire grows with the feed pH at 4.0-4.5. That is where my bicarbonate goes to zero. Nothing bad happened and the media pH finished around 7 without issues.
Against my better judgement, I listed to InTheShed and ditched my reliable pH down routine and incorporated the maximum amount of ammonium that I am willing to use. Because according to InTheShed, this is "how the pros do it". Despite only 4% of pros actually doing it that way.
That regimen resulted in a peat media pH of 7.8 by the 4th week of veg. The ammonium didn't control the pH of the media. Experience tells me that this is where leaf issues start to occur with my system, so I entered my proprietary citric acid flush mode which is NOT even supposed to work at all according to a mod at THC Farter.
So it turns out, I was able to drop a 5 gallon bucket of 7.8 pH peat down to 6.4 pH with only 10 gallons of my proprietary citric acid flush. I also had some mature seedlings in 1 gallon pots that were already up to 7.3 pH. They were easier to fix than the big buckets in veg. They required much less citric acid flushing at a lower acid concentration and higher pH.
The key to a successful citric acid flush is to think more in terms of grams of acid rather than pH. First, we need to use enough acid to completely remove ALL the bicarbonate from the water. If the result is 4.3 pH when zero bicarbonate occurs, that water has almost zero ability to reduce the ph of the media. So we need to add even more acid to produce a negative residual alkalinity for the flushing agent. How much acid to add after zero bicarbonate is achieved depends on how much bicarbonate and carbonate we need to neutralize in the media.
I used 15 grams of citric acid per gallon of tap water. That's a lot. My bicarbonate is about 75 ppm before acid. This dropped the pH of my proprietary citric acid flush down to 3.2. If your water bicarbonate is higher than mine, you would need to use more acid to get down to 3.2 pH. My runoff dropped from 1400ppm to 480ppm.
I didn't need to get so extreme with the mature seedlings. They only needed a flush with 4.0 pH citric acid. I have also previously used this less extreme version of acid flushing to reduce 5 gallons of alkaline media by smaller amounts such as dropping the pH by 0.2-0.5 with similar amounts of flushing.
So now that I have that bro science experiment under my belt, I shall return to acidifying my feed which removes or reduces bicarbonate from the tap water. This results in a lower media pH over time. It's the main reason to acidify tap water. I have done entire grows with the feed pH at 4.0-4.5. That is where my bicarbonate goes to zero. Nothing bad happened and the media pH finished around 7 without issues.
Peat Phreak
Well-Known Member
Incorrect for several reasons. In the case of citric acid, it also acts as a chelator and a biostimulant. The other acids do not. The other acids provide nutrients. Neither are a wasted step.
Simply acidifying tap water reduces bicarbonate. This is a benefit. Not a waste.
As you can see from my bro science experiment, it is possible to influence media pH quickly by using the right amount and the right kind of acid for the job. Citric acid does not add to NPK. If you try this acid flush with Phosphoric or sulfuric acid, you might end up with way too much new P or S in the media from the flush.
What percentage of the total nitrogen was derived from ammonium
Is this a commercial available product (ie Pro Mix or Sunshine Mix) or a peat mix of your own blending?
Peat Phreak
Well-Known Member
15% of N was from ammonium. Media is SS#4. Usually starts at 6.0 pH.
