plants need oxygen,.. but do that HAVE to get it in there water?

[Peanut Butter]

simple test.....take a DWC setup and shut off the air pump and see how long the plants last be4 they start to go to shit.


Ebb/flow lets the roots dry out so they have time to air out.

Aeropoincs has extremely well aerated water spraying on roots.(millions of tiny drops flying through the air have a ton of surface area)

DWC has well aerated res because of the surface agitation of bubbles constantly rising to the surface.

Soil has time to dry out and allow the soil to breath.

NFT water is constantly in motion making a large surface area and well aerated water.

All growing system are designed to get air/oxygen to the roots, because its a requirement of the plants.

 

[purpledomgoddes]

water, oxygen, root environ, cation exchange, etc

water, oxygen, root environ, cation exchange, etc

fundamentals of how plants use water+oxygen. no intent to bicker here. if convinced plants dont uptake oxygen from roots, have right to that idea. science is many ideas tested/experimented/truths found. just trying to contribute in positive way. enough data below to sift thru+do own research on, via reference. then make informed decision about inclusion/exclusion of oxygen from root-zone.

physical behavior of hydrogen, oxygen and water
the chemical composition of water is h20. this means that there are, generally, 2 atoms of hydrogen and 1 atom of oxygen per molecule of water. water associates, or unites w/ one another to form a loosely bound lattice of molecules having a pseudo-crystalline nature.
the degree of molecular association increases as the temp of liquid water decreases.
therefore, it is not absolutely correct when water is represented as being made of molecules that contain 2 atoms of hydrogen and 1 oxygen. h20.
a more precise way to write the formula (h20)x, where x is 1, 2, 3, 4,... because x is indefinite, chemists continue to write the formula as h20.
this is becuase that oxygen atom is constantly being recirculated, like in an ebb n grow system.
the bond that is necessary to unite two simple molecules of water results from the attraction of a positive(+) hydrogen atom of one water molecule for some of the electrons of an oxygen atom of a second water molecule. this bond, is referred to as the hydrogen bond or the hydrogen bridge.
h h
h+h--->h:---h:--->
h h
edit:actual chemcial formula wont post properly; top+bottom h bonds in wrong place.

oxygen freely breaks away from water, in other words. so, the roots are well adapted the intake of oxygen via water itself, even w/out addition of airstones, diffusers, etc. the electro-chem properties of the water itself breaks down into hydrogen and oxygen. both are necessary in the root environment for healthy plant growth.

root environment
rooting media provide plant support, serve as a source of water and plant nutrients, and permit diffusion of oxygen to the plant roots. during respiration, oxygen moves into the roots and carbon dioxide moves out. the media should have sufficient pore size and distribution to provide adequate aeration and moisture retention necessary for acceptable crop production.

the series of enzymic reactions that result in the utilization of oxygen, the release of carbon dioxide (c02), and the transfer of energy from glucose and other molecules to atp and other energies is cellular respiration.

oxygen is carried to the cells, and carbon dioide is carried from them by simple diffusion.

the roots of plants may be asphixiated if surrounding media is packed too tightly, as in a swampy area.

photosynthesis
occurs: in cells of green plants.

raw materials: water (h20) and carbon dioxide (c02)

time of occurrence: only when light shines upon cell

energy: stored in process

matter: results in increase of weight of plant

products: oxygen and organic materials

respiration
occurs: all living things

raw materials: oxygen and organic substances such as glucose

time of occurrence: continuously, night and day

energy: released by the process

matter: results in decrease in the weight of the plant/animal

products: carbon dioxide (c02) and water (02)

cation exchange
when inorganic salts such as commercial ferts are added to water, they dissociate into electrically charged units called ions.
positively charged ions (cations), such as hydrogen (h+), potassium (k+), calcium (ca++), magnesium (mg++), ammonium (nh4+), iron (fe++), manganese (mn++), and zinc (zn++), are absorbed mostly on the negatively charged surfaces of the media colloids (or, in 'air', 'oxygen'/nutrient solution in nft/dwc/aero). cations exist in small quantities.
negatively charged ions (anions), such as nitrates (n03-), phosphates (hp04--), sulphates (s04--), and chlorides (cl-), occur almost entirely in the solution.
anions can leach away w/ overwatering.
as plants absorb nutrients (ions) they exchange them.
for uptake of one potassium (k+) or ammonium (nh4+) ion, one hydrogen (h+) ion is released into solution/media.
for uptake of one calcium (ca++) or one magnesium (mg++) ion, the root releases two hydrogen (h+) atoms.
reason why ph drops, or becomes more acidic, as cations are absorbed, like ammonium nitrogen, solution amasses more hydrogen (h+) ions.
likewise, as the plant aborbs more anions, like nitrates and phosphates, more hydroxyl groups (0h-) and bicarbonates (h3o3-) are released into media/solution. removal of anions (like nitrate nitrogen) make ph increase, or more alkaline.

water transport
the transfer of water into root hairs and across epidermis, cortex and endodermis into the xylem in the stele is capillary. the concentration of solutes in capillary water is low and hypertonic to fluid w/ in root hairs.
water molecules diffuse from a region of high concentration to a region of low concentration.
eventually, water gets to the xylem, increasing osmotic pressure w/ in ducts in plant. the root pressure is one factor that moves sap upward through the root and stem and into leaves. water vapor is then constantly escaping from the leaves by transpiration. new molecules of glucose+other organics are formed in the leaves by photosynthesis and sent via the phloem to the roots. these two processes maintain hypertonicity of the sap in the roots and the absorption of water continues.
oxygen is required throughout the entire process - in the roots, and in the ambient atmosphere. oxygen permeates nearly every living thing+energizes vital functions w/in metabolisms of plants and animals.

so, the plant needs the water and oxygen to make simple sugars. gardens keep rh lower to further facilitate this process. when rh is low (high vapor pressure deficit), more water+nutes are pressured upwards and out of the plant. when rh is high (low vpd), the plant senses the higher pressure of water vapor on the outside of the plant and cannot push out as much water. 24 torr, or ~4.65 pound-force psi, is 100% rh. less than that and plant feel deficit. less than 20% atmopspheric oxygen is deficit to plant.

objectively, given the science, withholding oxygen from plant roots would seem to foster no identifiable benefit. gas exchange is as important in the media/root zone as it is in the general garden environment.

hope this helps. enjoy your garden!

 

[mpd]

Man, I had the power go off due to Hurricane Ike last year. Without power, the plants drowned almost immediately due to a lack of oxygen. I cried. They were just starting the bloom stretch.

I haven't been the same since they died. You should think about what you're doing because the sadness that comes from killing off a great grow is almost too much to bear...

 

[Haps]

It is quite simple to keep plants alive for days without electricity, just by adding dissolved oxygen manually to the water, then adding it back to the system.
H

 

[FreezerBoy]

The point of the discussion is not whether or not it's feasible to use airstones in your reservoir, but whether or not the plants can actually absorb oxygen (via water) through their roots.

Put your plant in a bucket with no drainage, fill it to the brim with water, and your plant will drown.

Place it in a DWC, fill it to the brim with water, the plant will not drown. It will thrive! Growth becomes explosive!

Both scenarios are identical with one exception: Oxygen to the roots or the lack thereof.

The reason DWC and Aero growth rates far outstrip other methods? They constantly flood the roots with massive amounts of oxygen. Do roots need to pull air out of the water? Only if they're submerged. Those roots that are not submerged pull oxygen out of the air or, out of the medium as water passes through, sucking air in after it.

All roots need oxygen. All roots absorb oxygen. Doesn't matter the system or substrate. Without oxygen to the roots, your plants are dead.

 

[Hydro-Soil]

Put your plant in a bucket with no drainage, fill it to the brim with water, and your plant will drown.

Place it in a DWC, fill it to the brim with water, the plant will not drown. It will thrive! Growth becomes explosive!

Both scenarios are identical with one exception: Oxygen to the roots or the lack thereof.

The reason DWC and Aero growth rates far outstrip other methods? They constantly flood the roots with massive amounts of oxygen. Do roots need to pull air out of the water? Only if they're submerged. Those roots that are not submerged pull oxygen out of the air or, out of the medium as water passes through, sucking air in after it.

All roots need oxygen. All roots absorb oxygen. Doesn't matter the system or substrate. Without oxygen to the roots, your plants are dead.

DWC is the number one killer of cannabis through asphyxiated roots. People underestimate how much air they need to pump through the water and how temperature affects how much the water can hold.

If you can, stay away from DWC in any environment that has any kind of temps over 70F. You're plants will thank you.

 

[geopolitical]

Plants have TWO kinds of roots generally, air roots and water roots. Both have different surfaces, both exchange gas and fluids differently. I've seen papers stating that high end aeroponic systems result in "hybrid" root structures, but I have no experience with this.

Plant roots have lenticels not stoma, although lenticels are not limited to root areas. These pores enable oxygen to reach the intercellular spaces of the interior tissues and carbon dioxide to be released to the atmosphere.

So yes, roots "breathe" at least in a limited fashion.

Now remember, roots aren't sterile systems. They hold vast colonies of happy bacteria idealy, and those critters DO need fairly high DO. So while keeping your lenticels supplied with air might help the plant a little bit, supplying your happy bacteria with enough DO (dissolved oxygen) will help the plant a LOT.

 

[FreezerBoy]

DWC is the number one killer of cannabis through asphyxiated roots. People underestimate how much air they need to pump through the water and how temperature affects how much the water can hold.

If you can, stay away from DWC in any environment that has any kind of temps over 70F. You're plants will thank you.

DWC is the #1 preventer of death through asphyxiated roots. The whole point of DWC is massive amounts of oxygen. If you're not doing massive amounts of oxygen, you're not doing DWC.

With enough DO and an absence of organics, I've kept res temps in the 80's. NOT a recommendation!!!! Just an experiment to see what rot actually looked like that I was happy to fail at.

 

[Hydro-Soil]

DWC is the #1 preventer of death through asphyxiated roots. The whole point of DWC is massive amounts of oxygen. If you're not doing massive amounts of oxygen, you're not doing DWC.

With enough DO and an absence of organics, I've kept res temps in the 80's. NOT a recommendation!!!! Just an experiment to see what rot actually looked like that I was happy to fail at.

Ok, I'll rephrase that. DWC, improperly set up, is the #1 killer. But why bother with all the 'massive' oxygenation if you don't have to? I resisted it for years but the switch to E&F and Drip has been Sooooooooo rewarding. I don't have to worry about heat, turbulent water noise, air-pump noise or res temps. Very freeing

Ya pump it through the hydroton/lavarock and gravity oxygenates it. Easy to silence, evaporation creates a humid root zone and your plants thrive the same as in DWC.

Did I mention you can also put the res somewhere else, other than in the flower cab? Sometimes that can make all the difference in the world.

 

[PurplePotion]

DWC requires air pumps cuz the roots are submerged under water, but does eb and flow use air pumps to oxygenate the water? How about aeroponics, and all the other types of hydro grows? If the roots are left exposed to the air for a length of time (not in the nute solution) can you ditch the air pumps?

Ebb and flow and aero are probably the only two venue you can get away without an airstone.. Aero I'm not too familiar with so I won't talk it about any more.

The way ebb & flow effectively works is by flooding out all of the old air and replacing it with nute solution. At the end of each flood cycle, fresh oxygenated air is pulled or sucked into your medium due to negative pressure.

Air stones never hurt though.. unless you put something in your res that's gonna foam.

 

[Hydro-Soil]

The way ebb & flow effectively works is by flooding out all of the old air and replacing it with nute solution. At the end of each flood cycle, fresh oxygenated air is pulled or sucked into your medium due to negative pressure.

Correct. You can actually 'Aerate' your nutrient solution if you flood enough times in a day. During flower there's a 12hr period of darkness and a huge drop in water demand by the plant so I don't water then. This is the only reason I leave an airstone in it is for that 12hrs. Probably overkill but hey.

 

[grapeman]

I don't need help growing or setting up a hydro grow guys, thanks for all your advice, but I'm just posing a question and it would really be nice if someone could address only it. No offense but forget what you think you know about what im doing. So again,.. do the roots NEED to get oxygen from the nute water or if say they were (every few seconds) no longer in the nute water, could they get said oxygen directly from the air.

I don't need help growing or setting up a hydro grow guys, thanks for all your advice, but I'm just posing a question and it would really be nice if someone could address only it. No offense but forget what you think you know about what im doing. So again,.. do the roots NEED to get oxygen from the nute water or if say they were (every few seconds) no longer in the nute water, could they get said oxygen directly from the air.

To ask such a question but preface it with the first sentence is ignorant.

 

[maryjanesjungle]

To ask such a question but preface it with the first sentence is ignorant.

I said "thanks for all your advice" but what i said after that still needed to be said, somehow. I preempted it with a niceity to let everyone know i was in fact thankful for there help. That's all anyone can do via type and it doesn't make me ignorant in the least. For you though, to go back 3 pages just to rip someone, on only your 3rd post on this site,.. well i think we all know who's really "ignorant". Other then this douche bag who added NOTHING to this conversation good info everyone.

 

[Hydro-Soil]

So again,.. do the roots NEED to get oxygen from the nute water or if say they were (every few seconds) no longer in the nute water, could they get said oxygen directly from the air.

If you're talking about 'dipping' the roots every few seconds, who knows? I say try it and see. Worst case scenario you kill a few plants.

It's doubtful though. Aeroponics sprays the roots (which oxygenates the nutes before they hit the roots) E&F and Drip systems rely on evaporation and gravity to pull air into the pockets of the medium. Dipping doesn't do that and is simply a sheet of water dripping from the roots.

Try it and stop trying to have everyone trying to guess what you mean. I don't think a single person here really understood what you meant by that question.

 

[maryjanesjungle]

I don't think a single person here really understood what you meant by that question.

seemed like a pretty straight forward English spoken question to me,.. i am trying it though, and so far, its working

 

[FreezerBoy]

But why bother with all the 'massive' oxygenation if you don't have to? I resisted it for years but the switch to E&F and Drip has been Sooooooooo rewarding. I don't have to worry about heat, turbulent water noise, air-pump noise or res temps. Very freeing

Grower personality is probably the most overlooked aspect of growing. Add garden specifics, and comparisons between systems become harder still. I started with E&F and find DWC far easier and hands off. Doesn't mean it would be for everybody because no one else is me or has my garden.

Anyway I've been in a foul mood lately. Apologies for unneeded grumpiness.

 

[Hydro-Soil]

Grower personality is probably the most overlooked aspect of growing. Add garden specifics, and comparisons between systems become harder still. I started with E&F and find DWC far easier and hands off. Doesn't mean it would be for everybody because no one else is me or has my garden.

Anyway I've been in a foul mood lately. Apologies for unneeded grumpiness.

FB, if that's you being grumpy I'll deal with it any day. LOL Yer a good egg.

 

[Hydro-Soil]

seemed like a pretty straight forward English spoken question to me,.. i am trying it though, and so far, its working

Sweet Try to keep as much detailed info as possible for future reference. Especially if you post it.

I've found a lot of things that helped me just from reading about something someone did and posted thoroughly. Not necessarily the information they were looking to put out, but definitely valuable to myself at any rate as I read between the lines a lot.