I had considered RO but had read that the PH will creep up when exposed to air. Currently have open barrels - 200 litres of water. If they were filled with RO water and allowed to sit a day or two, do you think the PH would creep up much if used within a few days of filling? Getting an RO filter/system just seems like it would less of a headache than dealing with hard water that leaves everything with a thick white salt crust.
Do we need to pH adjust our nutrient solutions?
- Thread starter InTheShed
- Start date
will look into what current percentage is, thanks
Diatomacious
Well-Known Member
Yes the pH will creep up due to interaction with the atmosphere. RO is almost pure water and it does not take much to change the pH. When you add your fertilizer it will alter the pH even more than the air so it should not matter in the long run. I wouldn't bother worrying about the pH of RO water as the soil will negate any effects the air will have on it. Once you add your fertilizer then worry about the pH as most fertilizer is acidic.
^^^^This^^^^
Look at the top of page 2. It has suggested percenatages of Ammonical Nitrogen to Nitrate Nitrogen based on water Alkalinity. At 150ppm you should be around 25% Ammonical. That said, I have 150ppm water too and have "gotten away with" many crops using Mega Crop and other fertilizers that are almost entirely Nitrate Nitrogen. The last run I used Jack's Nutrients 15-5-20 which is 20% Ammonical and had good results and the first couple years I grew I used Dyna-Gro Foliage Pro which is around 33%. Either would be a good option if you have upward pH drift due to your higher Alkalinty water. If you're really intersted in those 2 options, I can give you further supplement and feeding schedules.
Bud from the Jack's Harvest
Plants grown with Jack's and Pro-Mix in 150 ppm tap water
bruno12345
Well-Known Member
If youre substrate pH isnt already off the lines you can try to achieve balance through N.
Alkalinity of 150PPM can be counteracted with 35-40% ammoniacal nitrogen.
Ratio of ammoniacal N can be decided by alkalinity.
People with low alkalinity (30-60 or less) can use 10% or less ammoniacal N.
Medium alkalinity 60-150 can be counteracted with 20-30%
150 to 250 - 40%.
Source: Approximate guidelines to matching ammoniacal nitrogen levels in fertilizer with alkalinity from water to achieve a stable pH over time. Researchers Paul Fischer and William Argo.
Although, if you already off, that wont do, as these ratios are for balancing, and not correcting pH.
For correcting a too high soil pH, you should acidify your water to 5.8 or 6.2, and use around 30% ammoniacal N through a week or two, monitor your soil to see when to stop Ammoniacal N.
Also one must remind that, ammoniacal toxicity is prone to happen at high quantities, especially at cold substrates/winter time, so acidifiyng may bring a safer adjustment than using more than 40% Ammoniacal N.
Lets remind that urea and URAN are Weak acidifiers. We must aim at MAP or Ammonium Sulfate, those are strong acidifiers.
Alkalinity of 150PPM can be counteracted with 35-40% ammoniacal nitrogen.
Ratio of ammoniacal N can be decided by alkalinity.
People with low alkalinity (30-60 or less) can use 10% or less ammoniacal N.
Medium alkalinity 60-150 can be counteracted with 20-30%
150 to 250 - 40%.
Source: Approximate guidelines to matching ammoniacal nitrogen levels in fertilizer with alkalinity from water to achieve a stable pH over time. Researchers Paul Fischer and William Argo.
Although, if you already off, that wont do, as these ratios are for balancing, and not correcting pH.
For correcting a too high soil pH, you should acidify your water to 5.8 or 6.2, and use around 30% ammoniacal N through a week or two, monitor your soil to see when to stop Ammoniacal N.
Also one must remind that, ammoniacal toxicity is prone to happen at high quantities, especially at cold substrates/winter time, so acidifiyng may bring a safer adjustment than using more than 40% Ammoniacal N.
Lets remind that urea and URAN are Weak acidifiers. We must aim at MAP or Ammonium Sulfate, those are strong acidifiers.
Diatomacious
Well-Known Member
The real question is is the substrate pH too high from the water alkalinity. If the water is not affecting the pH of the soil then no need to worry. Peat based substrate has a lot of buffering capability.
BhangMan
420 Member
This is such a great question and one I struggled with for a very long time. Right now my base media of choice for a long time has been: 50/50 Coco to Perlite by volume. I amend with dolomitic lime, gypsum, and silica to pH ready this base to around 5.5-5.7. The nutrient I use is a water soluble pro horticulture grade tomato fertilizer available to the general public thanks to Amazon and other online retailers. The tap water I'm using (de-chlorinated) has a pH of about 6.75. So, I have learned to leave it alone most of the time. It simply doesn't need to be adjusted any because once it saturates my media pH will balance out nicely as the media moisture saturation levels decline through evaporation, uptake, and expiration. However, I've also learned that a minor adjustment to pH down to around 6.0 -6.3 can be beneficial to some strains during veg and 6.4-6.5 during flo. Those are tricky to play with, though. My point is, it's best to not even bother adjusting the pH to my water most of the time. This is because I have already amended my coco to handle a balance of pH before I've even added any water to it at all. When I do adjust down, I have to use a tiny amount of white vinegar to do it. I'm talking about using three or four pipette drops into a liter of water to achieve a pH move down from 6.7 to 6.5. It's a very, very, small amount to get the adjustment right. Then I add my nutrients to my desired EC depending on where the strain is on its growth cycle.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). 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!
All of the above info is STRICTLY for 50/50 bases using coco with perlite or coco with vermiculite or coco with alternative fiber, etc. In the end, you really don't need to adjust the pH of your water in this media if you're using the right nutrient and have amended your base correctly. You can just go ahead and use regular de-chlorinated water making sure you get the right amount of runoff of 10-30%, test the pH and EC of each runoff to see and record where you're at, and adjust nutrient EC levels as needed.
I will add that this is a very inexpensive way to go about my grow. All materials cost next to nothing. Nutrient is used in such small quantities that a 1lb. supply of the stuff will last me so long I tend to use it outside on my lawn shrubs and garden each year so I can buy a fresh batch for my indoor cannabis grows. It's a dirt cheap set-up and produces high quality plants if you have the time and right indoor environmental conditions met.
- Thread starter
- #388
I'm glad what you have going is working for you BhangMan! I would still advise anyone in coco to pH their nutrients to around 5.8, since coco (with or without perlite) is considered hydro. Folks in hydro should be pH adjusting their nutes.
BhangMan
420 Member
Cool. Coco is not considered Hydro. It's considered soilless. There are three total media bases cannabis horticulturalists and botanists are using: Soil, Soilless, and Hydroponic.
So, coco with perlite is soilless and just perlite is hydro? The article does mention scoria as inert like bark and coco, and scoria is very much like perlite. What about pumice? It actually has a CEC?
- Thread starter
- #391
Soil is humus-based, soilless is peat-based, and coco, water/aero, and hempy are hydro.
Coco is considered hydro:
"Coco is almost a neutral medium, which means that aside from its limited ability to adjust pH to optimum levels, it does not bind nutrients and feed them slowly to the plant over time like traditional “soils” do. (This means that Coco has a relatively low cation exchange capacity (CEC) compared to most “soils”. All the nutrients your plant needs to grow must be provided by you."
"Coco is basically neutral in its pH value and will not neutralise the pH value of the nutrient solution"
As I mentioned in my opening post, pH needs to be adjusted for non-buffered media.
As I mentioned, if you have a system that works for you that's great. But coco is hydro and pH'ing the nutrient solution into the hydro range is highly recommended.
BhangMan
420 Member
Well, it depends on where you're getting your coco from. Actually it ranges in pH between 5.2-6.8 if Google is right. The coco I use sits right around 5.2 before I amend it. After it has been amended I end up somewhere in the 5.7-5.8 ballpark. I've never actually made a tea and tested it, though. Once amended I don't have to do anything if I don't want to but water with nutrient each and every time being sure to flush.
Anyway, I'm definitely not trying to argue. But there's no way I'm going to consider coco with amendments growing hydroponic, either. I've been doing this for too long.
There's a guy with a YouTube vid, Prof. Bruce Bugbee from Iowa State. He's trying to sell his Apogee light measurment tools. But he's also explained the way cannabis researchers use these types of soilless media bases. Debacco does the same thing, but you have to put together a bunch of his short vids to piece it together. In the end, though, most teaching environments use this type of grow media as part of their studies. Growing in soilless media has a very high degree of control attached to it. Flushing and resetting are easy compared to other medias.
I don't go about it exactly the way Bugbee presents it. In my case, I have to use different levels of amendments because I'm not using Peat. I also have to adjust my nutrient levels with each watering differently than he recommends and have to add silica because I'm not wild about inhaling vermiculite dust. But, it's damn close to what I do, that's for sure.
- Thread starter
- #393
I've watched that video, and I recall his recommendation is for peat and vermiculite as a growing medium. I don't recall him recommending coco.
BhangMan
420 Member
Watch it again.
- Thread starter
- #395
Pass.
What is the brand of tomato fertilizer that you use?
I don’t mean to necro an old thread but I did not see anywhere explaining the best method to test your soil ph. I saw a few suggestions but is there a general consensus about the most accurate method? I’ve heard soil ph testers can be inaccurate but it was just hearsay.. should I pickup a tester or is there a more accurate/preferred method?
I apologize if it was covered and I missed it.. this thread has a lot of info to process lol
I apologize if it was covered and I missed it.. this thread has a lot of info to process lol
Having a lab test it is probably the only way that's spot on accurate. I think doing a slurry would be second best in my opinion.
Interesting.. I’ve never done a slurry test.. I’ll have to dust off the digital ph meter, last time I tried to use the drops on runoff it didn’t work out so well lol
- Thread starter
- #400
No worries Keffka! There are two ways to check the pH of your medium: slurry test and the pour through method. Either one works well enough for our purposes, and these are the methods used by major university ag departments on both field and container media.
Here's the info on slurry testing, and it requires distilled water and a calibrated pH meter to work, and this is how to do it:
• Take samples from a few different places where there are roots (dig down a bit rather than just use the top - I often stick a spoon down the outside edge of the pot to grab some from there as well)
• Add an equivalent amount of distilled water as grams of soil (10 grams of soil, add 10ml water). If that doesn't make a slurry, use enough distilled water to make a stirrable-but-thick slurry.
• Stir it up, wait 15 minutes, stir again. Do that for an hour and then put your calibrated pH stick in the water. That's the pH of your medium.
The pour-through test is done this way:
1. water containers to saturation (so that a few drops of water come out of the bottom of the container) with the normal irrigation water they have been receiving
2. after container has drained for one hour, place a saucer under the container
3. pour enough distilled (DI) water on the surface of the container to get 50 mL (1.5 fluid ounces) of leachate to come out of the bottom of the container (Table 1)
4. collect leachate for pH testing
5. calibrate pH meter
6. measure pH of samples
