Atami is charged with nutrient. They use a whole process
to get it to that point and you loaded it with more fert's.
I'd be real surprised if it needs a rinse at all & you could call or email Atami to speak to them about it.
-
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passive plant killer
- Thread starter delta9nxs
- Start date
Atami is charged with nutrient. They use a whole process
to get it to that point and you loaded it with more fert's.
I'd be real surprised if it needs a rinse at all & you could call or email Atami to speak to them about it.
hey, people!
silversurfer, i looked at your pics and i'm thinking, what's he doing planting in feb. then i realized where you live.
i'm itching to try that trashcan thing. temp control would be my biggest worry. the original study was done in Hawaii which is mid to high 80's f. though.
good luck, please let us know what happens.
onegreenday, yep, as soon as i saw that 1550 reading i knew i had washed out something they had put in. but i just recharge it with calcium nitrate and magnesium sulfate and it seems to work out fine.
silversurfer, i looked at your pics and i'm thinking, what's he doing planting in feb. then i realized where you live.
i'm itching to try that trashcan thing. temp control would be my biggest worry. the original study was done in Hawaii which is mid to high 80's f. though.
good luck, please let us know what happens.
onegreenday, yep, as soon as i saw that 1550 reading i knew i had washed out something they had put in. but i just recharge it with calcium nitrate and magnesium sulfate and it seems to work out fine.
Yup feb here is generally warm and dry. Average about 22-24 C day time temps. Wont have to worry about frost until june/july... One in a different spot is thriving 
I just received a jar of granulated calcium nitrate in the post. What rate to you use it?
Cheers!
I just received a jar of granulated calcium nitrate in the post. What rate to you use it?
Cheers!
@ delta9nxs...
how do you mix the solution?
arent calcium & sulafate supposed to be mixed separately?
to decrease precipitation?
a few passages that were observed/re-read...before, mixing calcium nitrate & potassium nitrate, w/ fnb &/or maxi-bloom:
repeated steps 1-7, inserting maxibloom for potassium sulfate & response seemed nice.
what are your methods/steps?
enjoy your garden!
how do you mix the solution?
arent calcium & sulafate supposed to be mixed separately?
to decrease precipitation?
a few passages that were observed/re-read...before, mixing calcium nitrate & potassium nitrate, w/ fnb &/or maxi-bloom:
&, from crop production practices:
repeated steps 1-7, inserting maxibloom for potassium sulfate & response seemed nice.
what are your methods/steps?
enjoy your garden!
hi, mistress!
i've read about raw salt mixing sequences and you do have to be very careful how you do it.
but i just dump the fnb in first, stir the hell out of it, then dump the calcium nitrate in, stir the hell out of it, then the magnesium sulfate and, you guessed it, stir the hell out of it.
in addition to the stirring, which is accomplished with a canoe paddle, i have a mag-drive 950 on a breaker wand recirculating the solution.
i think i get away with this because i'm not mixing raw salt ferts, i'm using a highly refined, buffered, stable product and then not putting much on it.
the calcium nitrate is greenhouse grade and the rite aid brand epsom is the best i've ever used. they both go instantly into solution.
so far it's working and i've never had any precip in the res. i've removed solution from the res and let it stand in a clear glass for a few hours. no precip.
later, d9
i've read about raw salt mixing sequences and you do have to be very careful how you do it.
but i just dump the fnb in first, stir the hell out of it, then dump the calcium nitrate in, stir the hell out of it, then the magnesium sulfate and, you guessed it, stir the hell out of it.
in addition to the stirring, which is accomplished with a canoe paddle, i have a mag-drive 950 on a breaker wand recirculating the solution.
i think i get away with this because i'm not mixing raw salt ferts, i'm using a highly refined, buffered, stable product and then not putting much on it.
the calcium nitrate is greenhouse grade and the rite aid brand epsom is the best i've ever used. they both go instantly into solution.
so far it's working and i've never had any precip in the res. i've removed solution from the res and let it stand in a clear glass for a few hours. no precip.
later, d9
I am slow. This work was supposed to be done a month ago. This is my new veg area. 7X7 frame on the floor lined with a 20 mil pond liner and a 10 mil rip stop tarp.
The bulb will be a new 1k hortilus hps. Run bare because I can control the heat better in this room.
The ballast is wired for 240v as I have an old ac socket there to plug into.
I have built a control bucket and plan to move my vegging plants today. Hopefully more pics later.
The bulb will be a new 1k hortilus hps. Run bare because I can control the heat better in this room.
The ballast is wired for 240v as I have an old ac socket there to plug into.
I have built a control bucket and plan to move my vegging plants today. Hopefully more pics later.
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Just a few pics to show my progress. All veg containers are now linked. They are all set at 4.5” by the control bucket. They were filled through the control bucket to insure that all lines were flowing correctly. I don't have the volume tank hooked up yet, i'll do that tomorrow.
Now I get to find the ideal water level, nute feed strength, etc. more fun.
Now I get to find the ideal water level, nute feed strength, etc. more fun.
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here are some pics of the volume tank hook up. it is maintaining a 4.5" water level in all reservoirs.
i want to point out to anyone new that this is a non-circulating gravity fed water supply.
each plant should draw solution independently and at a rate in concordance with it's individual needs.
now i need to regularly monitor ph and tds to determine exact ph and input strength for the volume tank.
i want to point out to anyone new that this is a non-circulating gravity fed water supply.
each plant should draw solution independently and at a rate in concordance with it's individual needs.
now i need to regularly monitor ph and tds to determine exact ph and input strength for the volume tank.
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...nicely detailed steps of your system, delta9nxs...
should not be that difficult maintaining levels (ppm/ec/ph) once flowering starts.
especially w/ trees; as they will drink mini-res amount in 24-36 hrs...
so...
nutrients levels can be controlled quickly w/ a smaller res. that requires pouring more into the system daily-48hrs... w/ larger res & more buffer, maybe just simple 1.0 ec/700 ppm (wand)... that really just 1-2 tsp fnb/maxibloom per day... w/ maybe 5-8 gal external res...
so, by next 24 hours, solution in res run out & replaced by new solution.
this constant new ec/adjusted ph (5.0-5.8) every 48hrs...
do this w/ 8x8x8 diy trough & ~7 gal containers... of diy permeable material...
basically... 5 gal water feed 4-6 big girl... all run-off used by plants... w/in 24-36 hrs.
repeat... only when .5-1cm solution on basin - & media top layer sparsely moist-drying...
if fed more than this, the run-off would not a) by drawn in by plant; b) evaporate; or c) be dehumidifed... w/in same period of 24-36hrs...
btw, that same 5 gal input of solution dehumidified w/in same period... this is how measure efficiency of inputs & that ventilation system works...
if did not have 24/7 air circulation, & correct temps @ correct moments... or vent/air cir process not work, can diagnose just by amount of water dehumidified - outside of garden.
hard to say this/that precise amount of water/nutes/ph adjustment required per xxx span of time... that very cultivar-dependent... there are some that are water-hogesses, there are some that prefer a brief drier period, betweeen waterings...
but... if correct, delta9nxs run same strain... & that it... so should be able to develop nice model of exact needs, of your kind
...thanks for sharing your methods... many may learn &(/to) grow
from your posts.enjoy your garden!
Hi, mistress! Thank you!
In this veg system I will have a total of about 60-65 gals. The trashcan/volume tank holds about 45 of those gals. So I will only have to top with new solution when it's nearly empty. I should be able to get a week out of it between fillings. None of the vegging plants uses as much as a plant in flower.
I started taking and recording readings last night. I initially used a 750 ppm solution at 5.8 at the same ratios (fnb, calcinit, epsom) as my 900 ppm solution by mixing at 900 ppm and then adding back more ro water to hit the number. I could do it from the other direction and not have to add more water but I know the ratio works and don't want to mess with it yet. When I find the correct input dose i'll re-figure it from the bottom to get new initial mixing amounts.
I am checking tds and ph in the volume tank, control bucket, and each reservoir #1-6. This should allow me to see if the reservoirs of plants at different stages of growth run at the same levels. It should also allow me to see if the direction of flow is truly all one way using readings from the control bucket. The volume tank should be rock stable as there is no possibility of interaction between it and the other bodies of solution.
One of the drawbacks of growing perpetually is that everything is a compromise. No two plants are in the same week of growth. As long as I get good growth with the big plants and am not burning the hell out of the small plants I should be ok in veg.
The new area is in a 400 sq ft room with good circulation so my temps and therefore rh are going to be more stable. The plants are already showing better. This has been an unusual winter here and i've been fighting low rh since december. Normally I get 1 or 2 low rh (under 20%) periods per year. A week or two each. This has been continuous since around the 15th of dec. Leaf curl, leaf twist, and i'm sure, a slightly lower yield.
Today i'll be whacking ppk #7. this one is the 70/30 turface/coco with a quart of worm castings. The buds are nice and thick.
Well, thanks for your input, later on
In this veg system I will have a total of about 60-65 gals. The trashcan/volume tank holds about 45 of those gals. So I will only have to top with new solution when it's nearly empty. I should be able to get a week out of it between fillings. None of the vegging plants uses as much as a plant in flower.
I started taking and recording readings last night. I initially used a 750 ppm solution at 5.8 at the same ratios (fnb, calcinit, epsom) as my 900 ppm solution by mixing at 900 ppm and then adding back more ro water to hit the number. I could do it from the other direction and not have to add more water but I know the ratio works and don't want to mess with it yet. When I find the correct input dose i'll re-figure it from the bottom to get new initial mixing amounts.
I am checking tds and ph in the volume tank, control bucket, and each reservoir #1-6. This should allow me to see if the reservoirs of plants at different stages of growth run at the same levels. It should also allow me to see if the direction of flow is truly all one way using readings from the control bucket. The volume tank should be rock stable as there is no possibility of interaction between it and the other bodies of solution.
One of the drawbacks of growing perpetually is that everything is a compromise. No two plants are in the same week of growth. As long as I get good growth with the big plants and am not burning the hell out of the small plants I should be ok in veg.
The new area is in a 400 sq ft room with good circulation so my temps and therefore rh are going to be more stable. The plants are already showing better. This has been an unusual winter here and i've been fighting low rh since december. Normally I get 1 or 2 low rh (under 20%) periods per year. A week or two each. This has been continuous since around the 15th of dec. Leaf curl, leaf twist, and i'm sure, a slightly lower yield.
Today i'll be whacking ppk #7. this one is the 70/30 turface/coco with a quart of worm castings. The buds are nice and thick.
Well, thanks for your input, later on
1 5 gal bucket, w/ 1 airstone, bubbling, should increase rh...
especially if placed behind oscillating fan.
maybe start w/ only 1 gal of water... to see how quickly it dissipates...
can also use small, cheapo comp, or >50 cfm fan, affixed onto lid of 5 gal bucket, to disperse water-saturated air.
yes... always interesting how differently plants grow, absopr water & nutes & such during veg & flower... this is where the 'dial' come in... especially w/ pepetual (never done).
seems as though delta9nxs has variables accounted for & even correcting+improving...
should be interesting w/ large res... prefer smaller, controlled doses, that can be assimilated in 24-48hrs... because maybe specific issue develop that require different solution/application...
in any event, nice garden! enjoy it!
especially if placed behind oscillating fan.
maybe start w/ only 1 gal of water... to see how quickly it dissipates...
can also use small, cheapo comp, or >50 cfm fan, affixed onto lid of 5 gal bucket, to disperse water-saturated air.
yes... always interesting how differently plants grow, absopr water & nutes & such during veg & flower... this is where the 'dial' come in... especially w/ pepetual (never done).
seems as though delta9nxs has variables accounted for & even correcting+improving...
should be interesting w/ large res... prefer smaller, controlled doses, that can be assimilated in 24-48hrs... because maybe specific issue develop that require different solution/application...
in any event, nice garden! enjoy it!
hey! finally finished whacking the plant.
yeah, i've thought about building a humidifier for the whole house.
normally the rh stays between 40-60 % all the time so i don't think about it until i need one and then it's too late, duh.
this was a good size plant and i think the heaviest so far. i'm thinking dry at around 9. We'll see.
a quart, or 1 part in 20 worm castings, 70/30 turface/coco. very hard nugs. no light, airy, fluffy buds here. these things go "thunk" when they hit the box top.
well, thanks again for your ideas. always welcome here.
yeah, i've thought about building a humidifier for the whole house.
normally the rh stays between 40-60 % all the time so i don't think about it until i need one and then it's too late, duh.
this was a good size plant and i think the heaviest so far. i'm thinking dry at around 9. We'll see.
a quart, or 1 part in 20 worm castings, 70/30 turface/coco. very hard nugs. no light, airy, fluffy buds here. these things go "thunk" when they hit the box top.
well, thanks again for your ideas. always welcome here.
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here is a root shot of yesterday's plant. good development but still a little too wet. this was #7 with a cloth wick, 3 more to go with cloth wicks before we see the media wicks.
putting my second all coco plant into 12/12 tonight.
looking forward to linking all plants in flower to a control bucket. for the first time i will have precision moisture control in flower with the ppk. the vegging plants are liking it.
putting my second all coco plant into 12/12 tonight.
looking forward to linking all plants in flower to a control bucket. for the first time i will have precision moisture control in flower with the ppk. the vegging plants are liking it.
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Hydraulic Redistribution
Hydraulic Redistribution
Introducing “Hydraulic Redistribution”.
In the beginning of this thread with plant or ppk #1, I maintained a strict “no top watering” policy after the first two weeks and I grew a decent plant. It produced 7 1/8 oz of dry bud. I guess I just wanted to see if I could do it with this new device. With each successive plant, however, I began top watering various amounts and frequencies to see if it would have a profound effect upon growth. What I found was that a small amount of top watering produced a better plant. The first plant had the lowest yield of any ppk to date. All subsequent plants have yielded more. What I found was that a very small amount of water applied several times a week to the top of the medium improved growth. I am not talking about enough water to supply the plant, but just enough to moisten the top. The plants were still getting the bulk (90% plus) of their water from sub-irrigation.
I had no clear explanation of why this was occurring, only that it was. I also wondered about the necessity of continuing this practice throughout the life of the plant. I have continued it to date at all stages of growth just because I didn't understand the mechanism.
I now think I know why and for how long.
I believe the top watering is useful in the early stages of root development while you are trying to fill the container with roots. Again, not enough to actually water the plant, but just to keep the top wet while roots occupy the space. We could call this the “wet” season. This parallels wet/ dry cycles in nature where most vegetative growth occurs in the early, and usually, wettest, part of the season. Cannabis, in most areas, finishes during the dry cycle. This is indicated in Robert Connell Clarke's “Marijuana Botany”.
I've been doing all kinds of media experiments to compare growth but was new to coco. The more I played with coco the more I liked it. I have committed to growing in coco and now have 8 plants in 100% atami brand coco. 6 in veg phase and 2 in flower. The roots at the end of 6 weeks veg were thick and white just below the surface. Totally occupying the surface of the medium.
Then I stumbled upon this. These are excerpts taken and edited somewhat by me from this link:
http://www.hydrol-earth-syst-sci-discuss.net/4/3719/2007/hessd-4-3719-2007-print.pdf
this paper should be read in it's entirety. Most of it is a presentation of the math used to model the phenomena, and the authors interpretations of that math. I can only pretend to understand some of it. But there are some excellent graphics used to illustrate the principles.
Also, this may be the strongest argument i've ever heard for utilizing a “dark” period during the vegetative phase.
“A model for hydraulic redistribution
incorporating coupled soil-root moisture
transport
G. G. Amenu and P. Kumar
Dept. of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801, USA
Received: 17 September 2007 – Accepted: 17 September 2007 – Published: 4 October 2007
One of the adaptive strategies of vegetation is the development of deep roots and the use of hydraulic redistribution which enables them to make optimal use of resources available throughout the soil column. Hydraulic redistribution refers to roots acting as a preferential pathway for the movement of water from wet to dry soil layers driven by the moisture gradient be it from the shallow to deep layers or vice versa. This occurs during the night time while during the day time moisture movement is driven to fulfill the transpiration demand at the canopy.
Hydraulic redistribution enables the movement of moisture from the upper soil layers to deeper zones during the wet months and this moisture is then available to meet the transpiration demand during the late dry season. It results in significant alteration of the profiles of soil moisture and water uptake as well as increase in the canopy transpiration, carbon assimilation, and the associated water-use-efficiency during the dry summer season. This also makes the presence of roots in deeper soil layers much more important than their proportional abundance would otherwise dictate.
Hydraulic redistribution can be defined as a passive movement of water via plant roots from relatively moist soil layers to drier soil layers.
In HR, plant roots form a conveyance system between soil layers through which water is transported. Therefore, moisture gets absorbed and released in response to gradients in water potential between the roots and the soil.
During day time, transpiration from the leaves via the open stomata creates a water potential gradient between the leaves and the roots, resulting in net water movement from the soil to the roots and then to the leaves. Water is absorbed from all depths depending upon the potential gradient and passes into the transpiration stream at the leaves. This is true both during wet and dry seasons. During night time, the stomata closes, resulting in turgor pressure that increases water potential within the plant body. As the potential in the root exceeds the potential in the drier part of the soil, moisture starts to efflux from the root to the dry soil, while water still continues to flow into the roots in the wetter part of the
soil.
Hydraulic redistribution is a reverse flow, in the sense that the moisture transport occurs in the reverse direction, from the root to the soil, than what transpiration dictates. The origin and evolution of this phenomenon is not clear yet, but there is much experimental evidence that shows its existence in numerous plant species. This evidence, coming from both laboratory and field experimental studies, shows that this process moves water through the soil profile at a much faster rate than could have been possible by gravity and diffusion in the soil matrix alone.
The root is assumed to absorb moisture from and/or release moisture to the soil, depending on the water potential gradient. In doing so, the root system is considered as a conduit for moisture transport from wet soil reservoirs to dry soil reservoirs, while at the same time conveying moisture to fulfill the transpiration demand at the canopy.
Plant roots can be viewed as a network of pipes consisting of xylem tubes.
In this system, the flow is governed by pressure gradient, established by the transpiration demand at the leaves, resulting in water being “pulled”.
For the case where hydraulic redistribution is incorporated into the model formulation, moisture movement between the soil and the roots is bi-directional, with moisture flow from the soil to the root or vice versa depending on the water potential gradient.
During night, water is transferred from a relatively wet part of the soil to a dry part of the soil via plant roots. During day time, water is taken up from all soil layers. The net water uptake profile, averaged over the entire period, shows a disproportionately high water uptake from the deeper soil layers with respect to the proportion of roots in those layers. A noticeable pattern is the nearly uniform uptake of moisture over the vertical profile.
The hydraulic redistribution is modeled by assuming the plant root system as a conduit for moisture transport along a pressure gradient.
The HR phenomenon makes the presence of roots much more important than their abundance for the deep soil layers. This study shows that HR enhances tremendously the contribution of deep roots to the water uptake by plants. The quantity of moisture taken up from deep soil layers is disproportionately high when compared to the proportion of roots at those depths. HR can be seen as a mechanism by which the vegetation makes optimal use of available water. It appears to be a water conservation mechanism for the plant’s usage that has adaptive importance and is most significant when deep roots are present. The mechanism may allow the plant to survive under extended dry periods.”
After reading this paper I believe the root system can be thought of as a very strangely shaped sack or bag with semi-permeable walls allowing two way transport of moisture, that is, from root to soil or soil to root, dependent upon transpiration in the canopy and the pressure differential created when it ceases.
Hydraulic redistribution can only occur during the “dark” or “lights off” phase. It can therefore be used as a management tool to manipulate the upper medium moisture content.
So, for me, the practical upshot of all this is that I will now top water only during the veg phase and will begin using 20/4 on/off timing during veg. I now believe that once roots are completely established throughout the container hydraulic redistribution will keep the top “air” type roots alive.
Later on, D9
Hydraulic Redistribution
Introducing “Hydraulic Redistribution”.
In the beginning of this thread with plant or ppk #1, I maintained a strict “no top watering” policy after the first two weeks and I grew a decent plant. It produced 7 1/8 oz of dry bud. I guess I just wanted to see if I could do it with this new device. With each successive plant, however, I began top watering various amounts and frequencies to see if it would have a profound effect upon growth. What I found was that a small amount of top watering produced a better plant. The first plant had the lowest yield of any ppk to date. All subsequent plants have yielded more. What I found was that a very small amount of water applied several times a week to the top of the medium improved growth. I am not talking about enough water to supply the plant, but just enough to moisten the top. The plants were still getting the bulk (90% plus) of their water from sub-irrigation.
I had no clear explanation of why this was occurring, only that it was. I also wondered about the necessity of continuing this practice throughout the life of the plant. I have continued it to date at all stages of growth just because I didn't understand the mechanism.
I now think I know why and for how long.
I believe the top watering is useful in the early stages of root development while you are trying to fill the container with roots. Again, not enough to actually water the plant, but just to keep the top wet while roots occupy the space. We could call this the “wet” season. This parallels wet/ dry cycles in nature where most vegetative growth occurs in the early, and usually, wettest, part of the season. Cannabis, in most areas, finishes during the dry cycle. This is indicated in Robert Connell Clarke's “Marijuana Botany”.
I've been doing all kinds of media experiments to compare growth but was new to coco. The more I played with coco the more I liked it. I have committed to growing in coco and now have 8 plants in 100% atami brand coco. 6 in veg phase and 2 in flower. The roots at the end of 6 weeks veg were thick and white just below the surface. Totally occupying the surface of the medium.
Then I stumbled upon this. These are excerpts taken and edited somewhat by me from this link:
http://www.hydrol-earth-syst-sci-discuss.net/4/3719/2007/hessd-4-3719-2007-print.pdf
this paper should be read in it's entirety. Most of it is a presentation of the math used to model the phenomena, and the authors interpretations of that math. I can only pretend to understand some of it. But there are some excellent graphics used to illustrate the principles.
Also, this may be the strongest argument i've ever heard for utilizing a “dark” period during the vegetative phase.
“A model for hydraulic redistribution
incorporating coupled soil-root moisture
transport
G. G. Amenu and P. Kumar
Dept. of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801, USA
Received: 17 September 2007 – Accepted: 17 September 2007 – Published: 4 October 2007
One of the adaptive strategies of vegetation is the development of deep roots and the use of hydraulic redistribution which enables them to make optimal use of resources available throughout the soil column. Hydraulic redistribution refers to roots acting as a preferential pathway for the movement of water from wet to dry soil layers driven by the moisture gradient be it from the shallow to deep layers or vice versa. This occurs during the night time while during the day time moisture movement is driven to fulfill the transpiration demand at the canopy.
Hydraulic redistribution enables the movement of moisture from the upper soil layers to deeper zones during the wet months and this moisture is then available to meet the transpiration demand during the late dry season. It results in significant alteration of the profiles of soil moisture and water uptake as well as increase in the canopy transpiration, carbon assimilation, and the associated water-use-efficiency during the dry summer season. This also makes the presence of roots in deeper soil layers much more important than their proportional abundance would otherwise dictate.
Hydraulic redistribution can be defined as a passive movement of water via plant roots from relatively moist soil layers to drier soil layers.
In HR, plant roots form a conveyance system between soil layers through which water is transported. Therefore, moisture gets absorbed and released in response to gradients in water potential between the roots and the soil.
During day time, transpiration from the leaves via the open stomata creates a water potential gradient between the leaves and the roots, resulting in net water movement from the soil to the roots and then to the leaves. Water is absorbed from all depths depending upon the potential gradient and passes into the transpiration stream at the leaves. This is true both during wet and dry seasons. During night time, the stomata closes, resulting in turgor pressure that increases water potential within the plant body. As the potential in the root exceeds the potential in the drier part of the soil, moisture starts to efflux from the root to the dry soil, while water still continues to flow into the roots in the wetter part of the
soil.
Hydraulic redistribution is a reverse flow, in the sense that the moisture transport occurs in the reverse direction, from the root to the soil, than what transpiration dictates. The origin and evolution of this phenomenon is not clear yet, but there is much experimental evidence that shows its existence in numerous plant species. This evidence, coming from both laboratory and field experimental studies, shows that this process moves water through the soil profile at a much faster rate than could have been possible by gravity and diffusion in the soil matrix alone.
The root is assumed to absorb moisture from and/or release moisture to the soil, depending on the water potential gradient. In doing so, the root system is considered as a conduit for moisture transport from wet soil reservoirs to dry soil reservoirs, while at the same time conveying moisture to fulfill the transpiration demand at the canopy.
Plant roots can be viewed as a network of pipes consisting of xylem tubes.
In this system, the flow is governed by pressure gradient, established by the transpiration demand at the leaves, resulting in water being “pulled”.
For the case where hydraulic redistribution is incorporated into the model formulation, moisture movement between the soil and the roots is bi-directional, with moisture flow from the soil to the root or vice versa depending on the water potential gradient.
During night, water is transferred from a relatively wet part of the soil to a dry part of the soil via plant roots. During day time, water is taken up from all soil layers. The net water uptake profile, averaged over the entire period, shows a disproportionately high water uptake from the deeper soil layers with respect to the proportion of roots in those layers. A noticeable pattern is the nearly uniform uptake of moisture over the vertical profile.
The hydraulic redistribution is modeled by assuming the plant root system as a conduit for moisture transport along a pressure gradient.
The HR phenomenon makes the presence of roots much more important than their abundance for the deep soil layers. This study shows that HR enhances tremendously the contribution of deep roots to the water uptake by plants. The quantity of moisture taken up from deep soil layers is disproportionately high when compared to the proportion of roots at those depths. HR can be seen as a mechanism by which the vegetation makes optimal use of available water. It appears to be a water conservation mechanism for the plant’s usage that has adaptive importance and is most significant when deep roots are present. The mechanism may allow the plant to survive under extended dry periods.”
After reading this paper I believe the root system can be thought of as a very strangely shaped sack or bag with semi-permeable walls allowing two way transport of moisture, that is, from root to soil or soil to root, dependent upon transpiration in the canopy and the pressure differential created when it ceases.
Hydraulic redistribution can only occur during the “dark” or “lights off” phase. It can therefore be used as a management tool to manipulate the upper medium moisture content.
So, for me, the practical upshot of all this is that I will now top water only during the veg phase and will begin using 20/4 on/off timing during veg. I now believe that once roots are completely established throughout the container hydraulic redistribution will keep the top “air” type roots alive.
Later on, D9
nice tech, delta9nxs
lookin good brotha, nice chunky tree you harvested there. cant wait to see the media wick'd ones 
take care
take care
howdy, everybody! i'm higher than Snoop Dogg!
thought i'd leave another little bit of info on hydraulic redistribution.
also, i wanted to report last weeks plant, #7, which i thought might hit 9 oz's, actually went 8.92. best plant yet.
"Science and engineering of natural systems
Tuesday, October 24, 2006
Hydraulic redistribution: Mass transport by underground tubes
Deep down, plants suck.
We should all have a good picture of how plants get water and why. Water is taken up by roots and is transported, along with nutrients, up into the plant through tubes called xylem. Essentially, once in the leaves, the H of the H2O is stripped away, and combined with C and O from CO2 to produce carbohydrates. The waste product, O2, is spat out through openings called stomata (oxygen – "they call it pollution, we call it life").
It’s impossible to suck up water above 10 metres in height (at least on Earth). Plants must rely on capillary forces to entice water up the narrow xylem, driven by evaporation of water inside the leaves and its movement out through the stomata. But something else is going on inside the darkness of the earth, in the plant’s hidden half.
For plants that close their stomata at night there is no upward flux of moisture from the roots to the stems. But that doesn’t mean water stops flowing in the roots. On the contrary, plant physiologists are finding an increasing number of species that exhibit what is known as hydraulic redistribution.
Roots have developed components that greatly restrict the movement of water out into the soil, but the gates aren’t 100% effective, particularly among younger roots. If some roots are located in dry soil, and others in wet, the water in the roots’ xylem will be subjected to a pressure gradient. The drier soil will be using the xylem as a straw to suck moisture from the wetter soil. This is a purely hydraulic phenomenon, not biological. Water within the soil can thus be redistributed from wetter regions to drier, provided the pressure gradient is strong enough to overcome the resistance imposed by the xylem. This only occurs in times of water scarcity.
If deeper soil is wetter, as is more often the case where hydraulic redistribution has been observed, the roots passively lift water into shallower soil. More water thus becomes available to the abundant shallow roots, to be taken up for photosynthesis the following day. Because water that would have otherwise infiltrated deeper, beyond the reach of roots, is shuttled upwards, more water is available for transpiration. This increase is small but significant, for both plant productivity and the water cycle.
The shallower water also allows greater absorption of nutrients, which are more often concentrated near the soil surface. What’s more, water lifted by deep-rooted plants becomes available to shallow-rooted neighbours (an example of facilitation; though this positive effect may be outweighed by the negative of out-right competition).
Hydraulic redistribution is a fine example of the overlap between physical and biological phenomena. Plants respond, and have perhaps even adapted, to the flux of moisture from wetter soil to dry, and it is roots through which the water is sucked".
thought i'd leave another little bit of info on hydraulic redistribution.
also, i wanted to report last weeks plant, #7, which i thought might hit 9 oz's, actually went 8.92. best plant yet.
"Science and engineering of natural systems
Tuesday, October 24, 2006
Hydraulic redistribution: Mass transport by underground tubes
Deep down, plants suck.
We should all have a good picture of how plants get water and why. Water is taken up by roots and is transported, along with nutrients, up into the plant through tubes called xylem. Essentially, once in the leaves, the H of the H2O is stripped away, and combined with C and O from CO2 to produce carbohydrates. The waste product, O2, is spat out through openings called stomata (oxygen – "they call it pollution, we call it life").
It’s impossible to suck up water above 10 metres in height (at least on Earth). Plants must rely on capillary forces to entice water up the narrow xylem, driven by evaporation of water inside the leaves and its movement out through the stomata. But something else is going on inside the darkness of the earth, in the plant’s hidden half.
For plants that close their stomata at night there is no upward flux of moisture from the roots to the stems. But that doesn’t mean water stops flowing in the roots. On the contrary, plant physiologists are finding an increasing number of species that exhibit what is known as hydraulic redistribution.
Roots have developed components that greatly restrict the movement of water out into the soil, but the gates aren’t 100% effective, particularly among younger roots. If some roots are located in dry soil, and others in wet, the water in the roots’ xylem will be subjected to a pressure gradient. The drier soil will be using the xylem as a straw to suck moisture from the wetter soil. This is a purely hydraulic phenomenon, not biological. Water within the soil can thus be redistributed from wetter regions to drier, provided the pressure gradient is strong enough to overcome the resistance imposed by the xylem. This only occurs in times of water scarcity.
If deeper soil is wetter, as is more often the case where hydraulic redistribution has been observed, the roots passively lift water into shallower soil. More water thus becomes available to the abundant shallow roots, to be taken up for photosynthesis the following day. Because water that would have otherwise infiltrated deeper, beyond the reach of roots, is shuttled upwards, more water is available for transpiration. This increase is small but significant, for both plant productivity and the water cycle.
The shallower water also allows greater absorption of nutrients, which are more often concentrated near the soil surface. What’s more, water lifted by deep-rooted plants becomes available to shallow-rooted neighbours (an example of facilitation; though this positive effect may be outweighed by the negative of out-right competition).
Hydraulic redistribution is a fine example of the overlap between physical and biological phenomena. Plants respond, and have perhaps even adapted, to the flux of moisture from wetter soil to dry, and it is roots through which the water is sucked".
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