can a brighter bulb than myself explain something to me?

[mowood3479]

I have been pondering a question...
If I have two plants.. each in 5 gal pots of promix.. The plants are the same age, hieght, genetics, etc...
will they recieve the same amount of nutrients if I feed one with 1 gallon of 1000ppm nutrient solution... and the next one with 2 gallons of 500ppm nutrient solution?

I guess what Im asking is how does nutrient uptake work? Is the plant merely taking up what i feed it? or only a portion of what I feed it...
any and all info is appreciated... I consider myself a very lay person so a little dumbing down could be helpful if at all possible...
thanks

 

[paladin420]

I was taught that the plant is smarter than me.(yes my teacher hippie chic knew me) and will up-take what they need.
If u watered once a day vs twice at the lower I think you mite see a difference. Nice question. Can u do a side by side ?

One of my water guys cut his nutes from 1500 to 750 and has never had better Lookin plants.

 

[mowood3479]

paladin.. my observations seem to agree with yours.. In the last few months.. I have gone from feeding @ roughly 1000ppm 2x a week to feeding @ 600ppm 3x a week.. the plants seem happy and I dont get any tip burning anymore... but??? anectdotal evidence is just that..suggestive but not definitive.

But I just want to know.. how it works, scientifically speaking..

 

[circadian clock]

1000 ppm is just that, 500 ppm x2 is still just 500 ppm. i think of it like this, if i can lift 100 pounds, then lift 50 pounds but lift it twice as much i still only lifted 50 pounds.

 

[Hammerhead]

less is more. I have never feed my girls anything over 2ec..The ave is around 1.8ec/800ppm. I have seen allot of issues com up at higher dosages. Its allot easier to get your garden dialed in starting at lower feeding dosages..

 

[sallyforthDeleted member 75382]

Yes less is best, agree with Hammerhead 800ppm is my optimum. Sometimes even 500 ppm, espeically with the Sativa's and Sativa hybrids.

 

[mowood3479]

I hear u guys and agree... but still wondering?? if i feed two identical plants in 5gal pots of promix... and mix one gal of nutrient solution @ 1000ppm n feed it all to plant one.. n then mix two gallons of nutrient solution @ 500 ppm n feed it all to plant two.. are they getting the same amount of feed?
how are nutrients uptaken by the plant? and does the amount of water matter?
in the scenario I posed they are being fed the same amount of nutrient... just one batch uses more water to do it..
anyone see what iam getting at? or am I not making sense?
sorry if im not..
mo

 

[circadian clock]

ex. nutes say mix one tablespoon to one gallon u get 1000ppm, now u mix one tablespoon to 2 gallons u get 500 ppm. this is just an example. so what im saying is if u give one plant one gallon of 1000 ppm the plant is recieving 1000 ppm. now if u mix 2 gallons up at 500 ppm ur still only feeding 500 ppm.double the water does not give u double the nutes the ppm is still 500. anymore questions we will be glad to help u.

 

[sallyforthDeleted member 75382]

Right, the one with 1000ppm will get just that.
When you double up the water, you will get 500ppm.
Personnally I would of thought that this experiment could also be based on other variables such as strain, stage of growth of each plant, for example, has one plant got more root mass than the other. Also they would need identical environmental conditions etc.

IME I would expect both plants to grow more or less the same, with the higher ppm maybe getting a little leaf burn at the tips of leaves.

I dunno, I'm high as fuck at the moment, so not sure if I'm making sense, so I hope this helps lol.

 

[PrivateAero]

Look into chelates. They force feed the plant and are why plants can get nute burn. Also your experiment wouldn't be good because it assumes more nuts are better. I believe .9 ec is perfect. btw use ec instead of ppm because the meters measure different and it's hard to have a conversation when two people think their talking about the same thing but aren't. they measure in .7 or .5 but often don't tell you which.

 

[mowood3479]

Im in no way saying more salts/nutrients are betteror worse... just using numbers that are easy to work with (ie 500 and 1000 and 1gal and 2gal)... we could use 300 and 600 ppm or 2 gallons and 4 gallons..
Im just wanting to know the why? how do plants utilize and uptake salts and how does the dilution of the salts in water effect the uptake... it would seem to me that the volume of water would make a difference... for example; is a plant going to recieve more nutrition/salts from a watering of one quart of water at 900ppm (.7 conversion) or a watering of 2 gallons at 450 ppm (.7 conversion).
I would think there has to be some sort of science on how plants utilize salts/nutrients and how the dilution ratio effects feedings...but maybe not.. no one seems to have much beyond "i feed at this ec/ppm and it works well".. or "lower ppm/ ec is better"...
I agree with these statements and have a feeding schedule that works well for me but I find myself pondering the why...
@private aero.. i will look into chelates... but I wasnt proposing an experiment, merely trying to find an answer to the question of how does the volume of water (in a nutrient solution effect the amount of nutrients the plant uptakes..
Is it as simple as feeding 1 gallon of nute solution @ 1000ppm is the exact equivelent of feeding 2 gal of nute solution @ 500ppm? providing there is no run off?

 

[mowood3479]

bump... anyone? this question will not leave my brain

 

[mowood3479]

pretty please... Ill pay $ to hear a substaintiated answer..

 

[Ziggaro]

Ahh its so frustrating asking questions here sometimes.
Everybody provides good information but nobody actually answers the question you asked.

A higher ppm is always going to provide more salts to the medium. The plant will try to uptake them and if there are too many salts it will burn.

I simply look at salts a dehydrator and too high of a concentration dehydrates the plant causing it to burn.

I read this paper with the goal of coming to explain it to you, but it gets rather complicated and I don't know how much biology you are familiar with so I'll post it for you.
http://www.ias.ac.in/resonance/July1998/pdf/July1998p45-52.pdf

 

[Ziggaro]

Basically from reading the paper ATP hydrolysis pumps ions across the cell membrane. These ions attract the nutrients and are transported across the barrier back into the cell.
This pumping requires water and I think that's where we run into problems. When theres not enough water to process the nutrients the plant takes it from it's leaves causing them get burnt.

 

[fungzyme]

To the original question: You're adding the same amount of salts to your soil mix (assuming no runoff). As to whether the plant receives the same amount of nutrients
that is dependent on a whole lot of other things, genetic and environmental in nature, and can make for huge variations from one strain to the next.

 

[mowood3479]

http://plantcellbiology.masters.grk...ysiology4-Absorption_Of_Mineral_Nutrients.htm
i
I think this explains it... if im reading it right it plants absorb minerals through several different (active and passive) actions... It involves a lot of chemistry but ions are exchanged from the plant to the soil and vice versa.. the plant uptakes what it has need for and leaves the rest... in the link above It suggests that plants absorb minerals faster initially from a lower dilution solution.. but that it levels out eventually..
SO I Could be very wrong but I think the answer to my question is what paladin said... that plants will uptake what they have need for and are not just being fed whatever is in the solution... (again, I mayb wrong.. just what ive come up with in an hour of reading..) would love to have a learned individual way in...
mo

 

[mowood3479]

fROM THE ABOVE LINK ^^^^^^
"ABSORPTION OF MINERAL NUTRIENTS
There are 113 or so different elements in this planet, of which fourteen or fifteen are absolutely required for the life processes without which plants exhibit diseased symptoms and ultimately die. Such elements which are absolutely required for the normal growth and development of the plant body are called essential nutrients. Among them, eight elements are required in sufficient quantities, others in small quantities; the former referred to as macronutrients and the latter as micronutrients or true elements. Nevertheless, plants also contain elements other than the elements mentioned above, whose deficiency may not cause any diseased symptoms or death and such elements are named as non essential elements. The macronutrients are carbon, hydrogen, nitrogen, phosphorus, potassium, calcium, sulphur, magnesium and iron. The micronutrients are manganese, zinc, boron, copper, molybdenum and cobalt. Non-essential elements are sodium, aluminum, silicon, chlorine, gallium, etc.
Most of the above said elements are found in soil solution either in the form of inorganic or organic salts or ions; which may exist in either in free state or bound to clay particles. Whenever there is depletion of any free ions from the soil solution, respective ions are released from clay particles into the soil solution to maintain the equilibrium. This is achieved by a process called ion exchange process. This may be due to contact ion exchange mechanism or by carbonic acid ion exchange ion mechanism.
CONTACT ION EXCHANGE MECHANISM
Plant roots are in contact with soil clay particulates which have colloidal dimensions, Root cells which are living, secrets hydrogen ions which are positively charged. Such ions can easily displace cations like K+, Na+ ions that are bound to clay particulates. Thus the cations are made available for the root system to absorb the required ion. But the relative retentive capacity of the clay particles, though not absolutely fixed, is in the order of H+>Ca2+>Ng2+>K+>NH4+>Na+. But hydrogen ions are capable of replacing any cation found on the clay particles. Nonetheless it appears that hydrogen ions can replace any bound ions to clay particles but there is a preference of ions to be released. As hydrogen ions have greater affinity, they can replace any of the above ions easily.


CARBONIC ACID ION EXCHANGE MECHANISM
Roots continuously respire irrespective of day or night, and liberate significant quantities of CO2, which when dissolved in soil water produces carbonic acids. Immediately they ionize into H+ and bicarbonate ions (HCO3)

The hydrogen ions thus formed are capable of exchanging with any bound cations on clay particles and make the bound cations available for the roots.

Though the above mechanisms were once proposed as theories, it is now clear that growing roots not only release CO2 but also secrete hydrogen ions. Thus the root does provide hydrogen ions for both carbonic acid ion and contact ion exchange processes. Similarly adsorbed anions are also exchanged by anions like OH-- ions.

STRUCTURES INVOLVED IN ABSORPTION
Aquatic plants do not need any special structures for the absorption of minerals, for the entire plant body acts as absorptive surface. But terrestrial plants possess extensive root system with innumerable growing apices. Short term radioactive isotope labeling experiments indicate that the meristematic regions of the root absorbs greater amount of ions than any other regions. This is perhaps necessitated by their active metabolic state. Though most of the minerals are absorbed by the growing meristems, minerals ultimately they find their way into xylem elements by active transport. From the xylem elements they move upwards along with transpiration stream and get distributed to all other regions.FACTORS THAT CONTROL ABSORPTION

Soil aeration: In most of the cases, living cells cannot survive without oxygen. As the roots contain a large number of living cells, they require considerable amount of energy for their metabolic activities and growth. So oxygen is absolutely essential for generating energy rich components by biological oxidative process. As mineral absorption requires energy, poor soil aeration affects the ability of roots to absorb adequate quantities of minerals. Water logged soils or soils with higher content of clay have very little amount of air; under such conditions roots are subjected to anaerobic conditions and the absorption of minerals is drastically affected. The inhibition of absorption of minerals due to the effect of respiratory poisons on roots clearly suggests that the absorption of minerals is an energy dependent process.
TEMPERATURE:

Soil temperature has a significant effect on roots metabolic activities and also it affects the mobility of ions in soil solution. If the temperature of the soil is lowered, absorption of minerals will be drastically reduced; but with the increase in temperature, the rate of absorption also increases, but up to certain limits. Drastic variations in the rate of absorption due to changes in the temperature suggest, the process is dependent on protein or enzymatic activity.

pH OF THE SOIL SOLUTION
The degree of ionization of minerals and other nutrients depends upon the hydrogen ion concentration of the soil solution. For example, most of the phosphate ions, at alkaline pH exist either as bivalent H3PO4 ions or trivalent H3PO4 ions. Such ions are not favored for absorption. On the other hand neutral pH favors the absorption of monovalent ions. So the soil pH has a significant effect not only on the rate but also the kind of ions uptake. This property is also due to its effect on cellular components that are involved in absorption, which further suggests that proteins are involved in the ion uptake. As the protein structure is very sensitive to pH, its function also changes if there is any change in the pH. That is why the maintenance of proper soil pH is very important in agriculture. Too acidic or too alkaline soil is virtually useless for cultivation. Until and unless the soils are restored in terms of pH, such soils remain as wastelands.


CONCENTRATION OF SOIL SOLUTION
Generally the concentration of minerals and its components found in soil solution is far below the levels of the same found in the cell sap. It means that the absorption of ions takes place against concentration gradient. The relative concentration of ions found in the cell sap and soil solution gives absorption ratio.

Ocean water contains relatively greater amount of salts than that of fresh waters. The land plants which are adapted to grow in fresh water soils die in marine water, because the marine water is enriched with greater amount of metal ions. Physiologically dry for them. But marine plant cells which have been adapted to such waters contain much more ionic contents than found in sea water. Even here, the ions are absorbed against concentration gradient.
The rate of absorption of ions very and depends upon the concentration of the soil solution. Normally, roots absorb greater amount of ions at a greater rate in dilute solutions than in a relatively high concentration solutions. How exactly the dilution enhances the rapid uptake is not clear, but it is a fact.
ION-ION INTERACTIONS
Soil solution consists of a wide variety of ions in different concentrations. While roots absorb inorganic nutrients, the ions of one kind present in the solution, either facilitate or interfere with the uptake of the other kind of ions. This phenomenon is called ion antagonism. On the other hand, a particular species of or ions enhance the uptake of
another kind of ions. Such a phenomenon is referred to as ion facilitated uptake.

Epstein has demonstrated that the absorption of K and Fe is antagonized by the presence of calcium and magnesium bivalent ions. Similarly CaCl2 has been found to inhibit the uptake of Cu2 ions and save the plants from copper toxicity. On the other hand, sodium chloride has been found to facilitate the uptake a wide variety of ions.

Such type of ion interactions leading to antagonistic or facilitated uptake is explained on the basis of carrier molecules. Different ions have different carriers or transport proteins. Because of the specific binding site, any ion that competes with the other ion for the same sites results in ion antagonism. On the contrary, a particular ion binding to carrier molecules facilitates the binding of specific ion and enhance uptake of the said ion. So the balanced inorganic nutrient is very important, otherwise roots absorb more of one kind of ions or the absorption f an essential ion may be prevented by the presence of another kind of ion.
IMPORTANT FEATURES OF ABSORPTION
1. Unequal absorption and specificity of ion:
If a mixture of different elements of equal molar concentration in the form of a buffered solution is provided to the root system, it absorbs some ions in greater amounts than other, the rest are absorbed in traces with variations. This indicates the unequal uptake and also specificity. Certain cells, at a particular stage of development, absorb specific ions because they are required for their metabolism. The specificity is demanded by the needs of cells or tissues. In spite of it, the pH of the external solution remains more or less neutral. This is certainly due to exchange of ions. This can be demonstrated by placing a tomato plant with its roots intact in a dilute solution of NaCl. After a period of time, certain ions like K and Ca2 are found in the external solution, which were not present before. This phenomenon explains the exchange of ions between the external solution and internal sap. Another equally important aspect of unequal uptake or absorption of ions is the dilution effect, where greater the dilution of external solution greater is the rate of uptake. This behavior is difficult to explain. Furthermore, the preferential uptake clearly suggests the role of specific carriers in the process of absorption of ions.
2. Salt Accumulation
Analysis of the concentration of specific nutrients present within the cell sap and the external solution reveals, that the relative concentration of specific components show greater concentration within the cells than in the external solution. Use of radioactive isotopes as traces also supports the same view, where certain ions are accumulated or taken in against concentration gradient. If the same is expressed in terms of chemical potential measured as milli volts. In Nietellas’ cellular cytoplasm, Na+ shows a chemical potential of 72 mV, potassium shows a difference of 40 MV and chorine +237mV. The above observations clearly suggest that the concentration of Na is very high in the external solution. In normal course, it should diffuse into the cell across the membrane by passive process, but to maintain chemical potential gradient and to prevent excess Na toxicity, Na ions are expelled out of the cell. On the contrary, the movement of CI is an uphill journey, because the concentration of them is many folds higher inside the cell than outside. The movement of ions inwards and outwards is referred to as ion flux and ion efflux respectively.
3. Saturation Effect:
If a root system is provided with an excess amount of specific ions, initially ions are taken up at a greater rate but later the rate of uptake remains steady and constant. This observation further suggests that for a given ion there is a fixed number of specific carrier sites; if all are loaded with their respective ions, the rate of uptake can not be increased until and unless the number of carriers is increased.
4. Metabolic Energy:
Energy is required for all metabolic processes. To demonstrate whether metabolic energy is required for ion uptake or not, it is possible to test it by providing respiratory poisons like KCN, DNP, rotenone, etc, to the root system engaged in the absorption of minerals. As soon as the inhibitors are added, the uptake of ions drastically reduces, which suggests that energy is absolutely required for the absorption of ions.
5. Apparent free space:
f a plant, with its root system intact, is provided with a known amount of radioactive ions like 35SO4 or 32P for about 30 minutes, it is possible to determine the total amount of ions taken up by the root system by measuring the amount of radioactivity left in the exogenously provided solution."

 

[mowood3479]

@ zIGGARO
reading the link you posted now... thanks

 

[2 Legal Co]

The Q, while a 'good one'... Does not have an answer.
Reason being; you don't know if the 1000 is Needed by the plant, Nor, do you know if the other plant can use the extra gallon of water.

You've not identified if that particular strain, or Phenotype of that strain needs heavy feed or if it/they, grow sufficient root structure to utilize the supply.

Keep in mind that changing one thing, can/will change others as well. Best advice I've had offered, is to start small/slow, and work up. Also keep in ming that the roots require air exchange, so a wet/dry cycle is required for root health.