Organic Soil, Microorganisms, and pH

Cann

Well-Known Member
Hey there weed nerds! Hoping to start a discussion here about the importance of pH in living organic soils. There seems to be a lot of misinformation spread by organic growers about the true importance of pH in a soil with a strong micro-herd. Recently I came across this post by WeeDroid on the grasscity forums. I hope its okay that I repost it here...


ph is not a worry with organic, living soils. What happens is that the plant roots give off exudates that attract appropriate microorganisms to the rhizosphere (root zone). All of these microorganisms adjust the ph for the plant.

Due to the CEC nature (causing nutrients to stick) of good soil and the gelatin like goo that the microorganisms create around the root ball, nutrients don't flush out.

Plants don't dump waste. They reuse nearly everything. The key is nutrient cycling which the soil microorganisms help with.

There are a few of us here that are exploring no till/reuse of soil grows. Even fewer of us have actually done it and found it to be a very viable way to grow. Check the organic growers forum here and search for no till grows.

There have been many many of us that have been deceived for all our lives by the petro chemical industries approach to farming and gardening. Luckily with the combination of established organic studies (Rodale Institute, Demeter, Oregon Tilth) and new research in soil life, we are beginning to see the beauty of nature in the soil and how to work in harmony with some very basic paradigms.

This results in healthier plants and less cost to the gardner.


This really made me stop and think...as I cultivate a healthy micro-herd in all of my containers yet I was worrying about pH a lot. I have no issues with my RO water (7.0 pH, 0 ppm) my problem arises with my AACT, which often has a pH below 5 even with the ppm only around 600. To compensate for this I have been adding pH up to my tea right before feeding to bring the pH to around 6.5. The problem is, I have to add a ton of pH up to bring it to 6.5 (2 or 3 TBS per 4 gallons) and doing so adds over 100 ppm to the solution, meaning roughly 1/7 of the ppm in my tea comes from pH up...which cannot be good for the soil (salts?). pH up is also the only non-organic ingredient in my whole garden - and that is really bugging me. So my question is: do you think it is more damaging to my soil to feed with a pH 6.5 tea with 100ppm pH up, or a pH 5.0 tea that is all organic and full of microorganisms. Could the pH up potentially be killing off my beneficial bacteria? Is the salt from the pH up going to get stuck in my soil causing lockout if I don't flush??? Has anyone had experience with pH issues in living organic soil, or is WeeDroid right that it is basically a non-issue if your soil is alive enough? I would love it if someone with experience could chime in, because I have a feeling I am drowning my ladies with kindness by worrying about pH so much and adding chemicals into my tea. Last grow I didn't have a pH meter and I mixed the same teas and applied them every few weeks the entire grow and had no issues at all...not sure if this was a fluke or if WeeDroid is really on to something here..

I use Roots Organic nutrient line if y'all are wondering - Buddha Grow, Buddha Bloom, HP2, HPK, Ancient Amber, Extreme Serene, and Trinity. I also use Roots Elemental as a Cal/Mg supplement for my RO water, and I use Blue Mountain Organics' Super Plant Tonic for my microorganisms, along with Roots Oregonism XL. Other ingredients that often make their way into the tea are Alaska Forest Humus, Earth Worm Castings, Neem Oil, and of course Blackstrap Molasses. Tea gets bubbled for 24-72 hours and then diluted to the proper ppm and fed. I have noticed a slight change in pH as the tea bubbles, usually it starts out around 4.5 and makes it way into the low 5's, although I am unsure if this is significant or not.

Chime in if you have anything to say, even if it is just your tea recipe or your nutrient feed schedule and pH. Wondering what other organic growers who run living soil are doing about this, it's an issue that never really seems to get much attention...

Peace :bigjoint:
 

Hemlock

Well-Known Member
Hey there weed nerds! Hoping to start a discussion here about the importance of pH in living organic soils. There seems to be a lot of misinformation spread by organic growers about the true importance of pH in a soil with a strong micro-herd. Recently I came across this post by WeeDroid on the grasscity forums. I hope its okay that I repost it here...


ph is not a worry with organic, living soils. What happens is that the plant roots give off exudates that attract appropriate microorganisms to the rhizosphere (root zone). All of these microorganisms adjust the ph for the plant.

Due to the CEC nature (causing nutrients to stick) of good soil and the gelatin like goo that the microorganisms create around the root ball, nutrients don't flush out.

Plants don't dump waste. They reuse nearly everything. The key is nutrient cycling which the soil microorganisms help with.

There are a few of us here that are exploring no till/reuse of soil grows. Even fewer of us have actually done it and found it to be a very viable way to grow. Check the organic growers forum here and search for no till grows.

There have been many many of us that have been deceived for all our lives by the petro chemical industries approach to farming and gardening. Luckily with the combination of established organic studies (Rodale Institute, Demeter, Oregon Tilth) and new research in soil life, we are beginning to see the beauty of nature in the soil and how to work in harmony with some very basic paradigms.

This results in healthier plants and less cost to the gardner.


This really made me stop and think...as I cultivate a healthy micro-herd in all of my containers yet I was worrying about pH a lot. I have no issues with my RO water (7.0 pH, 0 ppm) my problem arises with my AACT, which often has a pH below 5 even with the ppm only around 600. To compensate for this I have been adding pH up to my tea right before feeding to bring the pH to around 6.5. The problem is, I have to add a ton of pH up to bring it to 6.5 (2 or 3 TBS per 4 gallons) and doing so adds over 100 ppm to the solution, meaning roughly 1/7 of the ppm in my tea comes from pH up...which cannot be good for the soil (salts?). pH up is also the only non-organic ingredient in my whole garden - and that is really bugging me. So my question is: do you think it is more damaging to my soil to feed with a pH 6.5 tea with 100ppm pH up, or a pH 5.0 tea that is all organic and full of microorganisms. Could the pH up potentially be killing off my beneficial bacteria? Is the salt from the pH up going to get stuck in my soil causing lockout if I don't flush??? Has anyone had experience with pH issues in living organic soil, or is WeeDroid right that it is basically a non-issue if your soil is alive enough? I would love it if someone with experience could chime in, because I have a feeling I am drowning my ladies with kindness by worrying about pH so much and adding chemicals into my tea. Last grow I didn't have a pH meter and I mixed the same teas and applied them every few weeks the entire grow and had no issues at all...not sure if this was a fluke or if WeeDroid is really on to something here..

I use Roots Organic nutrient line if y'all are wondering - Buddha Grow, Buddha Bloom, HP2, HPK, Ancient Amber, Extreme Serene, and Trinity. I also use Roots Elemental as a Cal/Mg supplement for my RO water, and I use Blue Mountain Organics' Super Plant Tonic for my microorganisms, along with Roots Oregonism XL. Other ingredients that often make their way into the tea are Alaska Forest Humus, Earth Worm Castings, Neem Oil, and of course Blackstrap Molasses. Tea gets bubbled for 24-72 hours and then diluted to the proper ppm and fed. I have noticed a slight change in pH as the tea bubbles, usually it starts out around 4.5 and makes it way into the low 5's, although I am unsure if this is significant or not.

Chime in if you have anything to say, even if it is just your tea recipe or your nutrient feed schedule and pH. Wondering what other organic growers who run living soil are doing about this, it's an issue that never really seems to get much attention...

Peace :bigjoint:

I use dry soil acidifer in my soil to keep it below 7 I have used everything from ProMix to root organics soil and if you ph the soil before use it it runs high 7.0,
why because most of them use lime.
I feed aact teas every feeding and my tea PH is always hi so I PH my tea to 5.8. It still will just keep the soil under 7.
Seems to me you are adding a lot of PH adjuster.
 

SpicySativa

Well-Known Member
I'm still wrapping brain around this one, too...

My water comes out of the tap at about 30 ppms with a pH of about 8. Since it has such low tds (practically could be considered RO water) I feel the need to suplement calcium and magnesium. For this I have General Organics CaMg+. When I add the CaMg+ to my tap water, the pH drops below 5.0... When I ask questions about how (or if) I should address this (or read about how others have addressed this), I get many contradictory answers.

Some say don't worry about it (citing the dolomite lime and micro beasties in my soil), some say to use potassium silicate (it takes about a double dose of that stuff to bring the pH into range), some say to use Potassium bicarbonate (like the Earth Juice Natural UP), and some say to use GH pH UP (not organic)...

It's making my head spin...
 

Cann

Well-Known Member
I'm still wrapping brain around this one, too...

My water comes out of the tap at about 30 ppms with a pH of about 8. Since it has such low tds (practically could be considered RO water) I feel the need to suplement calcium and magnesium. For this I have General Organics CaMg+. When I add the CaMg+ to my tap water, the pH drops below 5.0... When I ask questions about how (or if) I should address this (or read about how others have addressed this), I get many contradictory answers.

Some say don't worry about it (citing the dolomite lime and micro beasties in my soil), some say to use potassium silicate (it takes about a double dose of that stuff to bring the pH into range), some say to use Potassium bicarbonate (like the Earth Juice Natural UP), and some say to use GH pH UP (not organic)...

It's making my head spin...
Okay thank you...glad someone else who knows their shit is confused by this. It seems the more I read about pH and organics the more confused and contradictory the answers are. Really wish I had a soil biologist to talk to or something. What WeeDroid said about CEC (Cation Exchange Capacity) got me reading, but honestly the more I read about CEC the less convinced I am that soil with high CEC will naturally stabilize pH or something of that nature...

I'm equally as nervous to feed with organic pH 5.0 tea as I am with the semi-organic pH 6.5 tea, I just have a feeling that the chemicals in general hydro pH up can't be doing much good... But pH 5.0 is over 10 times more acidic than what my ladies want, so it seems dangerous to feed that too often. I guess I'll just alternate waterings like so: pH 7.0 RO water, pH 5.0 unadjusted tea, pH 7.0 RO water, pH 6.5 adjusted tea, pH 7.0 RO water, etc. This should last me through the last 4 weeks of flower and at that point maybe I'll have figured out this conundrum.

Anyone with relevant info please chime in. If not we could just turn this in to a discussion about CEC because that seems to be extremely important and 99% overlooked by the cannabis community...not sure how that one slipped through...
 

Cann

Well-Known Member
me too...where are the resident soil biologists at???? prolly not lurkin on RIU haha
 

SpicySativa

Well-Known Member
For what it's worth, before I started using Subcool's super soil, I was using guano teas and AACTs applied to various soils (Fox Farms and/or Roots). I NEVER even checked the pH, and had great results. Now, with Subs super soil, I ran into what I believe were pH lockout issues after applying an AACT which was rather acidic...

It's possible something else caused my issues, but it was enough for me to revisit the pH debate...
 

Cann

Well-Known Member
Alright, well while we're waiting I'll repost some more knowledge from grasscity. Damn I'm high and that was just a 4 word w alliteration....looks real weird on the page :dunce: Anyway, on to the knowledge. This one comes from LumperDawgz - who IMO is one of the most knowledgable heads in organic gardening I have ever had the pleasure to find online - in organics he is on a level of his own above the legends of RIU (subcool, etc.) Unfortunately he hasn't made a post since 2010, so you have to dig through pages and pages old grasscity threads to find his gems of knowledge. If you are passionate about organics and furthering your knowledge of botany in general, I would suggest making an account on grasscity strictly in order to view Lumpers account, and then reading every single one of his 1,559 posts :mrgreen:. You'll thank me later.

Anyway, here is an example of his genius. Hope he doesn't mind me reposting this:


"Here's a few things to ponder perhaps.

CeC - the degree that a soil can absorb and exchange cations.

Cation -
a positively charged ion and in the case of soils, it refers to the basic cations, i.e. (NH4+, K+, Ca2+, Fe2+, etc...)

Anion -
a negatively charged ion and again in the case of soils, it refers to (NO3-, PO42-, SO42-, etc...)
Soil particles and organic matter contain negative charges on their surfaces. Mineral cations can adsorb to the negative surface charges or the inorganic and organic soil particles. Once the minerals are adsorbed they're not easily lost when the soil is leached by water and these minerals provide a nutrient release available to the plant roots via the soil foodweb. Minerals can be replaced or 'exchanged' by other cations, hence 'cation exchange'

NOTE: Adsorption
is the process of attraction of atoms or molecules (generically known as "monomers") from an adjacent gas or liquid to an exposed solid surface. Such attraction forces (adhesion or cohesion) align the monomers into layers ("films") onto the existent surface. The amount of these positively charged cations a soil can hold is described as the CEC and is expressed in milliequivalents per 100 grams (meq/100g) of soil. The larger this number, the more cations the soil can hold. A clay soil will have a larger CEC than a sandy soil.

The soil texture and organic matter content level plays the major role in a soil's overall CeC. Generally, the more clay and organic matter in the soil, the higher the CeC. Clay content is important because these small particles have a high ration of surface area to volume. Different clays also vary in CeC.

Smectites have the highest CEC (80-100 millequivalents 100 g-1), followed by illites (15-40 meq 100 g-1) and kaolinites (3-15 meq 100 g-1).

Base Saturation

The proportion of CEC satisfied by basic cations (Ca, Mg, K, and Na) is termed percentage base saturation (BS%). This property is inversely related to soil acidity. As the Base Saturation% increases, the pH increases. The availability of nutrient cations such as Ca, Mg, and K to plants increases with increasing Base Saturation%.

Base saturation is usually close to 100% in arid region soils.

Base saturation below 100% indicates that part of the CEC is occupied by hydrogen and/or aluminum ions. Base saturation above 100% indicates that soluble salts or lime may be present.

Can you say 'Cal-Mag' lockout? I thought you could! LOL

CEC and Availability of Nutrients

Exchangeable cations may become available to plants. Plant roots also possess cation exchange capacity. Hydrogen ions from the root hairs and microorganisms may replace nutrient cations from the exchange complex on soil colloids. The nutrient cations are then released into the soil solution where they can be taken up by the adsorptive surfaces of roots and soil organisms. They may however, be lost from the system by drainage water.

Additionally, high levels of one nutrient may influence uptake of another (antagonistic relationship). K uptake by plants is limited by high levels of Ca in some soils. High levels of K can in turn, limit Mg uptake even if Mg levels in soil are high.

Anion Exchange

In contrast to CEC, AEC is the degree to which a soil can adsorb and exchange anions. AEC increases as soil pH decreases. The pH of most productive soils in North America is usually too high (exceptions are volcanic soils & most rock dusts) for full development of AEC and thus it generally plays a minor role in supplying plants with anions.

Because the AEC of most agricultural soils is small compared to their CEC, mineral anions such as nitrate (NO3- and Cl-) are repelled by the negative charge on soil colloids. These ions remain mobile in the soil solution and thus are susceptible to leaching.

Flush it away!

There's a smidgen on CeC as it relates to soils.

HTH

LD"


discuss....
 

kushking42

Well-Known Member
we went down this road in the super soil under the sun thread. and some good info in the langbeinite thread as well. i use optimum cec when i design my soil mixes. best way to keep a plant healthy and happy. that and hi brix readings... have you been reading dr albrecht's research?
 

Cann

Well-Known Member
good lookin out, I'll get to reading those threads. I have indeed been reading Dr Albrecht's research, and it's some fascinating stuff. Really makes what's going on inside those pots so much more interesting, yet it adds another level of complexity when encountering soil problems :wall:.

In regards to the brix readings, what level do you shoot for with your brix? how do you measure it? I have a hydrometer for homebrewing so if I can use that I'm golden.

Do you pH adjust your nutrient solutions before watering? just curious.
 

rocknratm

Well-Known Member
im subbed like to see if any good answer comes about. I use liquid lime which is probably way too much calcium but I dont think it causes any problem. I ph to around 6.5 or as low as 6 because the RO line claims you dont have to ph at all. Still it makes me nervous not to ph. I should do a side by side (ph'd and not), but I always tell myself to to that and never do.
 

secondscollide

Active Member
You don't need to pH as long as you stay balanced.

...for instance, the person who was putting acidic A.A.C.T. into their super soil; super soil is already brimming with nutes and has a high ppm/low ph.

Before I finish in Super Soil, I use GO nutes w/ RO water and never have to pH. Especially when I bubble them with some Oregonism for 18-24 hours and get a nice foamy tea going. Lots of organisms = more ability to adapt and survive.

Your root-ball is a lot like a human colon. You need to have a load of healthy bacteria in order to adapt to lots of Nutes!

Daily pHing is for hydro growers, you don't need to pH organics unless you're troubleshooting.
 

Cann

Well-Known Member
Okay, I think I agree with you secondscollide, just looking for some actual science as to how the soil bacteria help buffer or regulate pH in relation to nutrient adsorption. I have a fairly good understanding of probiotics and the symbiotic relationship inside of our colons, but I don't know if this knowledge translates directly to soil biology.

I just want to be confident that I can water with pH 4.5 AACTs for my entire cycle and not ever have to worry about lockout issues....right now I just don't have that much confidence in the microherd to deal with that much acid...gotta remember that pH is logarithmic so pH 4.5 is literally 100 times more acidic than ideal (6.5)....somehow I just don't see the soil adapting to that extreme of conditions.

Has anyone watered with very acidic nutrients for a full cycle in organic soil and experienced no issues? I would love to hear some stories...
 

whitey78

Well-Known Member
Okay, I think I agree with you secondscollide, just looking for some actual science as to how the soil bacteria help buffer or regulate pH in relation to nutrient adsorption. I have a fairly good understanding of probiotics and the symbiotic relationship inside of our colons, but I don't know if this knowledge translates directly to soil biology.

I just want to be confident that I can water with pH 4.5 AACTs for my entire cycle and not ever have to worry about lockout issues....right now I just don't have that much confidence in the microherd to deal with that much acid...gotta remember that pH is logarithmic so pH 4.5 is literally 100 times more acidic than ideal (6.5)....somehow I just don't see the soil adapting to that extreme of conditions.

Has anyone watered with very acidic nutrients for a full cycle in organic soil and experienced no issues? I would love to hear some stories...

What your not considering is you arent feeding the plant, the micro herd is doing the feeding by what they excrete. There is a whole lot more to it than that but I cant remember exactly.. A book like teaming with microbes or something newer would give you (and me) a better understanding... But low PH really shouldnt affect the plants because they arent the ones getting fed directly.. They do get fed indirectly because there is usually some kind of NPK along with other elements in the things that are being brewed with teas for the most part. Its also important to watch out for how much NPK is going into teas etc...
 

Cann

Well-Known Member
Thanks whitey - your post seems to make a lot of sense

So what your saying is as long as the pH is within a range where the micro-herd can surivive, all should be well?

Good point about who exactly is dealing with the nutrients first, that really makes an impact on the importance of pH. It makes sense that in hydro where there are no micro-beasties and you are feeding nutrients that are immediately available to the plant, that the pH has to be perfect in order for the plant to get the full spectrum of nutes. This is why everyone stresses the importance of pH so much, because without a micro-herd you're pH has to be right on (even in soil) because the plant is doing all the work to make the nutrients available, and it can only do this within a certain pH range (roughly 5.5-6.8). Alternatively, it makes sense that if you are feeding complex nutrients (not immediately available like hydro nutes) to your micro-herd, as long as they can survive in the pH range of those nutrients (4-7) they should be able to do their job converting complex nutrients into simple nutrients that are immediately usable by the plant. Therefore the plant will receive a full spectrum of nutrients compliment of the micro-herd, regardless of the soil/nutrient solution pH.

So my question is, if that is the case, was it not the acidic AACT that caused Spicysativas issues with lockout in supersoil? I would love to believe that I can water with whatever pH AACT I want as long as it is brimming with micro-beasties, but hearing things like lockout from acidic teas makes me very skeptical. Spicy - is there anything else that could've cause the lockout? I just want some case studies of peoples' experience with unadjusted acidic AACTs and organic living soil...:-|
 

SpicySativa

Well-Known Member
I can't say 100% for sure that the acidic AACT caused my problem. It's possible that it was a matter of timing, not cause and effect. When the issue presented itself, I did this:

(1) Thinking the plants were hingry, I fed them some Earth Juice (very acidic). The problem continued to progress.

(2) Decided to correct pH for the remainder of the grow

(2) Fed them some Pure Blend Pro Bloom For Soil with pH adjusted to 6.5.

Around that time the problem seemed to screech to a halt. I can't say 100% for sure what fixed it or what caused it.
 

Cann

Well-Known Member
Hmmm....what was the pH of the Earth juice? And what type of lockout did you get? Would love to see pics if you got any...
 

MrGreenTooth

Active Member
seems it comes back around to what Sub said, I think it was Sub, PH under 6.2 the plant can't uptake nutes ... and never put anything on your plant that you are not 100 % sure about. Seems the plants respond well to ph' 6.5 or so, I think I'm going to always keep it adjusted before it hits the plant
 
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