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WHY cannabis nut uptake ph is different in soil and in hydro
- Thread starter Iamnumber
- Start date
Rico _El_Guapo
Member
Might have something to do with the soil life and how it buffers water, humic and fluvic acids must do something as well. In hydroponics the oxygenated water keeps the water “alive” per say.
There is something called Cohesion-Tension Theory if you are down for some reading.
This could be a very interesting topic, hopefully this thread gets some action
There is something called Cohesion-Tension Theory if you are down for some reading.
This could be a very interesting topic, hopefully this thread gets some action
I would guess it's because most soils have buffering agents in them. It's honestly a good question, and I've never looked this up before. But I'm a self-declared genius and I think my guess is pretty good. 
Seriously though, it makes sense, because certain ingredients of almost every soil mix are known buffering agents, and it can even be difficult to alter a pH of certain soils, no matter how hard you try. Most hydroponic media, on the other hand, is designed not to buffer anything, so you can really take advantage of the range in which cannabis plants uptake all of the nutrients, providing faster or more robust growth than the same plant would in soil.
Seriously though, it makes sense, because certain ingredients of almost every soil mix are known buffering agents, and it can even be difficult to alter a pH of certain soils, no matter how hard you try. Most hydroponic media, on the other hand, is designed not to buffer anything, so you can really take advantage of the range in which cannabis plants uptake all of the nutrients, providing faster or more robust growth than the same plant would in soil.
Science
I am poking around in the dark and counter arguments are my best guess.. nothing personal and no conclusive evidence..
Buffering agents:
These are an interesting subject worthy of a thread of their own.. But .. I see then buffering the ph of the medium .. NOT widening the intake range of the plant.
Life in soil:
hmm.. interesting.. I am of two minds here..
First con.. it is my understanding that plant would have wider ph range for accepting nutrients EVEN IF the soil is sterile. I have no science to back this up .. no research papers etc. testing without a lab would be hard as air is filled with life so sterile soil would not stay sterile very long and any experiment would soon be contaminated.
Second pro..
it is proven that mykorriza forms a symbiotic bond with plant (in root system) .. So it is very possible that there is a catalyst in the soil that widens the plants nutrient uptake.
con to this pro...
some coco is provided with mykorriza .. IF mykorriza is the key .. plants with this medium (still hydro grow afaik) should have wider ph range to accept nutrients .. and they might have!! we have no data on this ..
Third option:
as nutrients are readily available in hydro.. would it stand to reason that plant narrow down the intake range .. I mean that the shift in range would be plants self regulation system adjusting to the environment ? .. I mean like starving human or animal will eat nearly anything but one who is surrounded with abundance of different foods will only pick preferred ones?
Buffering agents:
These are an interesting subject worthy of a thread of their own.. But .. I see then buffering the ph of the medium .. NOT widening the intake range of the plant.
Life in soil:
hmm.. interesting.. I am of two minds here..
First con.. it is my understanding that plant would have wider ph range for accepting nutrients EVEN IF the soil is sterile. I have no science to back this up .. no research papers etc. testing without a lab would be hard as air is filled with life so sterile soil would not stay sterile very long and any experiment would soon be contaminated.
Second pro..
it is proven that mykorriza forms a symbiotic bond with plant (in root system) .. So it is very possible that there is a catalyst in the soil that widens the plants nutrient uptake.
con to this pro...
some coco is provided with mykorriza .. IF mykorriza is the key .. plants with this medium (still hydro grow afaik) should have wider ph range to accept nutrients .. and they might have!! we have no data on this ..
Third option:
as nutrients are readily available in hydro.. would it stand to reason that plant narrow down the intake range .. I mean that the shift in range would be plants self regulation system adjusting to the environment ? .. I mean like starving human or animal will eat nearly anything but one who is surrounded with abundance of different foods will only pick preferred ones?
pH is the measurement of the activity of free hydrogen (H+, acid) and hydroxyl (OH-, base) ions in a solution. Doesn't matter if the solution comes from soil or hydro. pH is pH! Nutrient absorbing plants don't care. Iron and other nutrients are locked out of soil and hydro, in the same pH range.
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IF so.. would you please explain the following image? (one of several variants available online).
link to image.. attaching image failed for some reason..
http://www.spliffseeds.nl/images/stories/spliffseeds/en/blog/pH-EC/pH-Cannabis-Nutrition-1.png?i=312
image is here fine as I write or edit but dose not show in my post.. go figure.. using the image button next to web link button
To me it looks clearly that plant uptake of nutrients AT ANY GIVEN PH LEVEL is dependent on medium.
To me this is common knowledge and I have accepted it as a fact. Now that you have claimed that this is incorrect.. I would kindly ask you to provide bit more substantial information as bases for your statement as it contradicts commonly accepted view.
Your Right bro, My bad, I'm talking about the root osmosis is dependent on nutrient concentration! That's being the only difference.
King Rat
Active member
the most common mistake is referring to any potting mix that is sold in hydro stores to be "soil"
nearly all of that 'soils' are peat based mixes and should therefore be treated like the hydro medias in terms of pH. peat has a low pH of 3-4 and is fortified with dolomite lime to raise the pH in a more acceptable range. that lime needs to be broken down and best done by watering with a pH like in hydro of 5.8 - 6.2
So if you ask me: No there is no different pH range to be used when watering potting mixes out of the store bought bags. Outdoor soil and organic mixes (and using organic ferts) is different.
nearly all of that 'soils' are peat based mixes and should therefore be treated like the hydro medias in terms of pH. peat has a low pH of 3-4 and is fortified with dolomite lime to raise the pH in a more acceptable range. that lime needs to be broken down and best done by watering with a pH like in hydro of 5.8 - 6.2
So if you ask me: No there is no different pH range to be used when watering potting mixes out of the store bought bags. Outdoor soil and organic mixes (and using organic ferts) is different.
Thanks King Rat, Sorry iamnumber, I didn't mean to step on your feet, I know what you are saying is right too. Just a mis understanding. Thank you
All is well my good man. Thank you very much for clearing up the miss communication!
I am sorry as well as I did use very blunt tone and a sledge hammer to hammer my point in .. as I could not see your reasoning at that time .. I evaluated your statement in my context .. I come from academic world where there are no shades of gray.. only true and false. written communication is lacking as the non verbal communication is excluded.I use the capital letter to emphesise key points .. I am aware that internet standard is 'shouting' .. still caps is the best easy&fast way to highlight key issue. shouting was never my intention .. my apologies if it was taken this way.
Very good reply.. really most of commercial soil mixes are peat
and perlite mixed,this cant be called soil-mixes..
am looked in most EU soil mixes and they are lack of true soil..
best soil is black or red with addition of wormcastings and quality
organic matter as humus.. this kind of soils is lot more easy
to buffer and they keep microlife more longer alive and active
so naturaly plants stay longer healthy in this kind of medium
than in those that are based on peat and perlite,no hard PH
swings..
Also look in beneficial bacteries,they also help that mycorhiza have
better action than whithouth it..
This is mix of 70% black rich humus soil and 30% of wormcastings... a real soil mix whithouth aerators of any kind..
one last comment
one last comment
Before I leave I'll want to share something interesting. "Ions such as Na+, K+, Ca2+, Mg2+, Cl −, SO42−, and NO3− can be regarded as "conservative" in the sense that their concentrations are unaffected by changes in the pH, pressure, or temperature (within the ranges normally encountered near the earth's surface and assuming no precipitation or dissolution of solid phases, or biological transformations)." I'm out of here! Thanks for the thread
one last comment
Before I leave I'll want to share something interesting. "Ions such as Na+, K+, Ca2+, Mg2+, Cl −, SO42−, and NO3− can be regarded as "conservative" in the sense that their concentrations are unaffected by changes in the pH, pressure, or temperature (within the ranges normally encountered near the earth's surface and assuming no precipitation or dissolution of solid phases, or biological transformations)." I'm out of here! Thanks for the thread
The manufactures of those potting mixes say they behave somewhat between soil and true hydroponics and recommend a nutrient solution ph just slightly higher than true hydroponic mediums.
Hydroton/DWC buckets/NFT toughs/ebb & flow tables etc are all inert. Their plastic and ceramic materials exert no effect of their own on the ph of the nutrient solution. That's not true with peat. Peat has an acidifying effect. To counteract that the makers of ProMix, SunshineMix etc have to add substantial amounts of dolomitic lime to the product. That buffering apparently changes how things play out in the route zone. Last I checked they were recommending a ph around 6.0.
GingerBeard
Member
Theory: root exudates
Plants in soil use root exudates in the form of H+ to exchange nutrients with the soil colloid. I’m not as up on nutrient delivery in soilless systems, though I suspect that delivery is more direct. The soil colloid provides a buffer for the exudates.
GB
Plants in soil use root exudates in the form of H+ to exchange nutrients with the soil colloid. I’m not as up on nutrient delivery in soilless systems, though I suspect that delivery is more direct. The soil colloid provides a buffer for the exudates.
GB
Thanks!! I did a quick google search on the key terms .. Looks very interesting and explains a lot of how plant interacts with the medium it grows in.
in DWC any change plant tries to make would be carried away..
in more static hydro .. the chages would stay local.. perhaps stationary hydro mediums just lack the compound plant needs to adjust medium characteristic to better suit itself ( this would be in effect the ability to intake nutrients in wider ph range than in hydro environment )
