Living soil dry back dilemma...

[lakesidegrower]

Can we chat about the concept of dry back and how it does or does not fit in with living organic soil?

I struggle with it.... lol I think the concept of how dry back benefits the grow makes sense, its almost intuitive, you can vibe with how a wilted plant must feel exactly the same way as you after a hot ass day without a drop, and then BOOM that beautiful glass of cold water, the best tasting thing you've ever had, its fucking LIFE!! Its something you can see in the plant, its a tangible perk and thrive, it forces the roots to dig deeper in search of water, - but it just doesn't seem to work in my head with organic living soil.

I think of the soil food web in my 20 gal pots as a steam engine; it takes a while to get that fire burning, feeding just the right amount to get that fire rolling and then when it does you add just what you need to keep it going, add to little and the engine slows, add too much and it starts to snuff the fire - so if we let that soil system dry out we are slowing down that fire drastically, and like the steam engine it will take a bit to get it going again. I know that in a natural dry back scenario, the microbiology will cyst up or otherwise go dormant, but the populations are slashed and will need to be rebuilt again, releasing available nutrients for the plant to consume. To me a dry back 'should' hurt the soil food web I've worked my ass off to nurture and cultivate.

I also do consider that even when soil feels bone dry there is still a decent amount of water there (capillary, I believe?) and so maybe the answer is there, that the degree to which the soil needs to dry back needs to hit a critical point before it has a discernible effect on the microbiome.

Right now I have Blumats in my pots; I have them dialed back to allow for a soil drench here and there without worrying that I am just watering on top of water, but every run there's always a point where I want to pull em to get that dry back satisfaction - today is one of those days lol

To me this really all comes down to the availability of nutrients at any given time, and that a dry back causes a dip in the availability of nutrients in the soil due to microbial suppression. If you run salts, a dry back works perfectly because you are constantly dumping chemically-available nutrients so no soil food web needed. But I also know people who run organics, not necessarily living soil, and they run a dry back with beautiful results the whole run.

Thoughts?!

 

[crimsonecho]

those microbes are probably hiding around in there somewhere but the actual numbers gets sliced of course however they do reproduce very fast and most likely many that take shelter attached to the roots in symbiotic relationship with the plant will not probably die off just because you add a day before watering the plants. besides the mass number of microbes dying would also provide more available nutrient for the plant once you water it with no runoff or anything.

having said all this shit i never feel comfortable letting my soil dry out and will not let that happen ever lol.

 

[mudballs]

In bacterial networks, drought increased connectedness (normalised degree) and centrality (betweenness) at post-drought samplings


basically bacteria colonies can be improved by drought, fungal colonies remain unaffected.
A widely observed phenomenon is an increase in the ratio of Gram-positive to Gram-negative bacteria under drought

It has been proposed that Gram-negative (GN) bacteria use more plant-derived C sources that are relatively labile, while Gram-positive (GP) bacteria use C sources derived from soil organic matter that are more recalcitrant.
my soil is extremely high in Carbon, and i even add some chopped up leaves to have more and more Nitrogen for later in the grow.
so dry back could help your Gram Positive communities, and Gram Positive are good for OLS(organic living soil). so dry backs can be proven to be beneficial to your microbiome, BUT! it takes 1-2 weeks for the network to recover and then it muscles up. So it seems if you employ dryback, you should only do it once or twice.
which microbes are the Gram Positive ones we want? idk i just woke up and dont wanna look right now, forgive me.keep flushing newbs, lol?

 

[lakesidegrower]

those microbes are probably hiding around in there somewhere but the actual numbers gets sliced of course however they do reproduce very fast and most likely many that take shelter attached to the roots in symbiotic relationship with the plant will not probably die off just because you add a day before watering the plants. besides the mass number of microbes dying would also provide more available nutrient for the plant once you water it with no runoff or anything.

having said all this shit i never feel comfortable letting my soil dry out and will not let that happen ever lol.

Thnx for the insight - so funny tho, at the end of the day it’s just seems like those of us who run living organisms it would rather die than let their pot dry out lol

you make a pretty darn good point about the mass microbe death event ending Up as good for the next generation. It takes what, 24-36 hrs to get an actively aerated compost tea brewing, you’d have to think tho that it would take longer in soil without active aeration.

How dry to you let it get at its driest, would you say?

 

[lakesidegrower]

Nice argument man, I like the support - I could totally see the stress on the bacterial populations caused from dryback having a net-positive impact on successive generations. Maybe that’s comforting for those of us who have felt the dread of finding a bone dry living soil pot lol short term pain for long term gain

but the practice of ongoing dryback cycles seems to just look like a bad sine curve of microbial, or maybe given the info above, specifically bacterial populations.

 

[lakesidegrower]

[QUOTE="mudballs, post: which microbes are the Gram Positive ones we want? idk i just woke up and dont wanna look right now, forgive me.keep flushing newbs, lol?
[/QUOTE]
I know that it refers to a type of staining used when scoping bacteria on slides… it has to do with a function of the permeability of the cell wall I believe.. this is first year microbio, I should know this

 

[lakesidegrower]

I forgot to note that the big issue I seem to experience with keeping a constant base moisture level in my pots is I have been getting N tox in all of my runs, I’m pretty sure that the constant moisture levels in the pots are at the very least working against me there.

I’m working on really seeing how far back I can dial the blumats to where they just maintain that ‘day before they need to be watered’ level and then I can run ‘modified baseline dryback’ (how’s that for corporate canna-ag slang?!)

 

[crimsonecho]

Thnx for the insight - so funny tho, at the end of the day it’s just seems like those of us who run living organisms it would rather die than let their pot dry out lol

you make a pretty darn good point about the mass microbe death event ending Up as good for the next generation. It takes what, 24-36 hrs to get an actively aerated compost tea brewing, you’d have to think tho that it would take longer in soil without active aeration.

How dry to you let it get at its driest, would you say?

in the end no matter how small there are living things in there and its because of me. i created this environment for them to live in and i feel responsible for their wellbeing. not like their god or anything but also i’m their god in a way, if they could they would build statues of me definitely rofl so i try to take care of my little guys

as for the driest i let them usually get is when i mulch i just lift the coco discs or whatever and if its starting to get dry (don’t mean got dry tho i mean just not properly wet anymore and just damp) i water. eventhough it takes 24 hrs to brew a tea you have to also take into account the original bacterial colony that goes into a tea. what a cup full of ewc in a gallon of aact versus 1 gallon i use in a organic matter rich 5 gallon pot. the actual microbe count and density should be pretty high compared to an aact and in an aact maybe each microbe has to reproduce 10 times versus 2-3 times in a gallon of ewc to have the same microbial density. so i think the colonies would recover very quickly from a small and acute drought as long as its not a chronic problem. thats my opinion tho no facts to back it up

 

[mudballs]

I know that it refers to a type of staining used when scoping bacteria on slides… it has to do with a function of the permeability of the cell wall I believe.. this is first year microbio, I should know this

I didnt remember it...just have enough base education i know what to look for and when. Great topic, good job man...feel good.
Edit, blueberry pineapple 4k cigarillos are insanely tasty

 

[lakesidegrower]

I didnt remember it...just have enough base education i know what to look for and when. Great topic, good job man...feel good.
Edit, blueberry pineapple 4k cigarillos are insanely tasty

damn those do sound good

I wonder if others who use blumats in living experience N tox...

Here's the deal on gram positive/negative:
"Bacteria with thick peptidoglycan are called gram positive. If the peptidoglycan layer is thin, it's classified as gram negative"
Basically the gram positive bacteria have a thick peptidoglycan layer with no 'harder' lipopolysaccharide outer shell, they are more permeable; gram negative bacteria have a thinner peptidoglycan layer but also have a harder protective shell layer, if you will. This makes gram negative bacteria the harder to kill one of the two. Gram negative bacteria produce endotoxins, gram positive don't (as much). The reason gram negative die off in drought conditions is purely due to osmotic pressure, they dehydrate in the absence of the thicker peptidoglycan layer, while the gram positive can retain moisture levels inside the cell wall because the thicker cell wall resists the fluctuations inside the cell.



It would be interesting to do a deeper dive into the ideal GP:GN ratio in soil, maybe there is a cannabis specific ratio that works best and maybe that can be controlled by dealing in your dryback and actually doing it in a quantifiable way by measuring that ratio over time...... maaaaybe this has all been figured out already and I'm new to the party...?!

in the end no matter how small there are living things in there and its because of me. i created this environment for them to live in and i feel responsible for their wellbeing. not like their god or anything but also i’m their god in a way, if they could they would build statues of me definitely rofl so i try to take care of my little guys

as for the driest i let them usually get is when i mulch i just lift the coco discs or whatever and if its starting to get dry (don’t mean got dry tho i mean just not properly wet anymore and just damp) i water. eventhough it takes 24 hrs to brew a tea you have to also take into account the original bacterial colony that goes into a tea. what a cup full of ewc in a gallon of aact versus 1 gallon i use in a organic matter rich 5 gallon pot. the actual microbe count and density should be pretty high compared to an aact and in an aact maybe each microbe has to reproduce 10 times versus 2-3 times in a gallon of ewc to have the same microbial density. so i think the colonies would recover very quickly from a small and acute drought as long as its not a chronic problem. thats my opinion tho no facts to back it up

no this is all good stuff, this makes me feel better about trying to get my pots to the near the driest the blumats will support haha
I also think you have it right there about the aact comparison; that's a good point.

 

[McShnutz]

damn those do sound good

I wonder if others who use blumats in living experience N tox...

Here's the deal on gram positive/negative:
"Bacteria with thick peptidoglycan are called gram positive. If the peptidoglycan layer is thin, it's classified as gram negative"
Basically the gram positive bacteria have a thick peptidoglycan layer with no 'harder' lipopolysaccharide outer shell, they are more permeable; gram negative bacteria have a thinner peptidoglycan layer but also have a harder protective shell layer, if you will. This makes gram negative bacteria the harder to kill one of the two. Gram negative bacteria produce endotoxins, gram positive don't (as much). The reason gram negative die off in drought conditions is purely due to osmotic pressure, they dehydrate in the absence of the thicker peptidoglycan layer, while the gram positive can retain moisture levels inside the cell wall because the thicker cell wall resists the fluctuations inside the cell.

View attachment 5089137

It would be interesting to do a deeper dive into the ideal GP:GN ratio in soil, maybe there is a cannabis specific ratio that works best and maybe that can be controlled by dealing in your dryback and actually doing it in a quantifiable way by measuring that ratio over time...... maaaaybe this has all been figured out already and I'm new to the party...?!



no this is all good stuff, this makes me feel better about trying to get my pots to the near the driest the blumats will support haha
I also think you have it right there about the aact comparison; that's a good point.

I have a digital blumat tensiometer I use with my blumat pump system. I shoot for a reading of 70 mbar. Ideal is 100 mbar, so keeping this in mind that the tensiometer threads onto a 9" maxi. My fabric raised beds is 17" deep.
So in my mind the top would be a bit drier than the middle and certainly drier than the bottom. Never dry, but slightly moist. The bacteria should be flourishing in the upper half

 

[JustBlazin]

You don't really want any dry backs in a organic living soil as far as I can tell. I also use blumats

Here's a good study on the subject

A plant-centered approach to watering - Greenhouse Canada

Does dry soil promote root growth? Research and greenhouse experience would disagree.

www.greenhousecanada.com

And here's a link to a post I made a couple years ago on the subject.

The Goldilocks Of A Moisture Zone

saw this post on another forum and thought it was very good, so i figured id put it up here "A GOLDIELOCKS OF A MOISTURE ZONE Hand-watered gardens or those on timers go through fluctuations of moisture levels. If you water in the morning for example, it is likely your plants are over-watered...

www.rollitup.org

 

[mudballs]

I care more about water potential, i try to avoid drybacks. I just like science stuff and according to what i could find, one dryback would be beneficial. But thats it.
Once you go from this.


To this


You dont do it again. You dont want to damage what you just beefed up. I guess for no-till you're gonna have to do it every once in a while.

 

[lakesidegrower]

I have a digital blumat tensiometer I use with my blumat pump system. I shoot for a reading of 70 mbar. Ideal is 100 mbar, so keeping this in mind that the tensiometer threads onto a 9" maxi. My fabric raised beds is 17" deep.
So in my mind the top would be a bit drier than the middle and certainly drier than the bottom. Never dry, but slightly moist. The bacteria should be flourishing in the upper half

Right - I think I've seen your posts about a fancy tensiometer, I googled and now want one as well. I'm a sucker for data, I'll take any I can get.
This brings up an interesting point of discussion; the fact you likely need to consider moisture levels at different horizons in a living soil pot, especially no till

 

[McShnutz]

I care more about water potential, i try to avoid drybacks. I just like science stuff and according to what i could find, one dryback would be beneficial. But thats it.
Once you go from this.
View attachment 5089201

To this
View attachment 5089203

You dont do it again. You dont want to damage what you just beefed up. I guess for no-till you're gonna have to do it every once in a while.

Now I want to learn more.
Very interesting

 

[McShnutz]

Right - I think I've seen your posts about a fancy tensiometer, I googled and now want one as well. I'm a sucker for data, I'll take any I can get.
This brings up an interesting point of discussion; the fact you likely need to consider moisture levels at different horizons in a living soil pot, especially no till

I'm a very practical thinking individual. And that being said, it flows into my garden and how it functions. Everything I do for my plants, I try to mimic mother nature. Think of our soil outside. The deeper you go the more hydration. The microbiology in soil is very extensive and located at varying depth and serves a particular purpose. Plant roots dont just go straight down, they spread out 180 degrees. Some are for water and others are oxygen and ions. I believe the same holds true for the symbiotic evolution with microbes.

 

[lakesidegrower]

You don't really want any dry backs in a organic living soil as far as I can tell. I also use blumats

Here's a good study on the subject

A plant-centered approach to watering - Greenhouse Canada

Does dry soil promote root growth? Research and greenhouse experience would disagree.

www.greenhousecanada.com

And here's a link to a post I made a couple years ago on the subject.

The Goldilocks Of A Moisture Zone

saw this post on another forum and thought it was very good, so i figured id put it up here "A GOLDIELOCKS OF A MOISTURE ZONE Hand-watered gardens or those on timers go through fluctuations of moisture levels. If you water in the morning for example, it is likely your plants are over-watered...

www.rollitup.org

I remember reading that thread! Is Northwood still around?
Great article - well I have no reason to disagree with any of the arguments there
'roots do not search for water, but for conditions that are ideal for root hairs'
I also liked this... 'Growers should not just water plants. Growers should operate root systems.'

What's your method for getting the blumats dialled in? I'm constantly second guessing myself, and worry about dry spots. I have three carrots in each 20gal, wonder if I should be adding some drippers.

I also just watered in a JMS yesterday - each pot took 4L of solution with no run off no problem, - I felt like that was plenty and thought adding more water was likely too much. The pots weren't dry beforehand, but I had dialled back the blumats a few quarter turns over a couple of days before the drench. I've marked the water line in my res, am curious when they start the drink - each pot holds 2 - 6wk vegged plants

 

[lakesidegrower]

I'm a very practical thinking individual. And that being said, it flows into my garden and how it functions. Everything I do for my plants, I try to mimic mother nature. Think of our soil outside. The deeper you go the more hydration. The microbiology in soil is very extensive and located at varying depth and serves a particular purpose. Plant roots dont just go straight down, they spread out 180 degrees. Some are for water and others are oxygen and ions. I believe the same holds true for the symbiotic evolution with microbes.

I can dig it - that's a good point as well - its easy to quickly accept that dry cycles are natural, in fact needed to mimic a natural plant life cycle, but that probably just aint true

 

[McShnutz]

I can dig it - that's a good point as well - its easy to quickly accept that dry cycles are natural, in fact needed to mimic a natural plant life cycle, but that probably just aint true

Oh no, not dry, but slightly moist. Similar to the forest. Underneath all that dry litter is a multi layer of materials that hold water and nutrients at different capacities. Consequently microbes inhabit the upper most and it's much dryer there than deeper down. Still never truly dry.

 

[Hollatchaboy]

Look into sips. Soil is constantly moist. Microbes and plant, never happier.