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vhGhost
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Calculating Nutrient levels
- Thread starter Lucas
- Start date
gregor_mendel
Active member
I see, Lucas. Leaving out weights, I got the same values.
In doing so, GH gets a value of 63 ppm for Mg, but we know with weight it is 73 ppm Mg.
The MN gets a value of 29 ppm Mg with no unit weight. We can assume it will also be higher when we weigh it (any volunteers?), but probably not the target of 60 ppm.
My point is that in a constantly wet medium, 10A+10B may fall short on Mg. My batch is too old to weigh, but if someone could find a unit weight for Metanaturals 3-3-3 and for Metanaturals 1-5-5 we can calculate what amount, if any, of epsom salts to add.
GM
In doing so, GH gets a value of 63 ppm for Mg, but we know with weight it is 73 ppm Mg.
The MN gets a value of 29 ppm Mg with no unit weight. We can assume it will also be higher when we weigh it (any volunteers?), but probably not the target of 60 ppm.
My point is that in a constantly wet medium, 10A+10B may fall short on Mg. My batch is too old to weigh, but if someone could find a unit weight for Metanaturals 3-3-3 and for Metanaturals 1-5-5 we can calculate what amount, if any, of epsom salts to add.
GM
gregor_mendel
Active member
I almost forgot!
With GH we get 106 ppm Ca without weight, 130 ppm Ca without weight.
The prescribed formula for MN has no Ca at all.
I realize that calcium is not on our list, but how do we know mj doesn't need it when we have been giving her so much with 0-8-16 (and roughly the same amount in Floranova Bloom) and she has been so happy?
5ml of metanaturals calcium per gallon gives 79 ppm Ca, and allows easy ratios of nutrient purchase. When we find unit weights for all 3, I suspect we may be able to use 7 or 8 ml of each to get very close to 0-8-16.
GM
With GH we get 106 ppm Ca without weight, 130 ppm Ca without weight.
The prescribed formula for MN has no Ca at all.
I realize that calcium is not on our list, but how do we know mj doesn't need it when we have been giving her so much with 0-8-16 (and roughly the same amount in Floranova Bloom) and she has been so happy?
5ml of metanaturals calcium per gallon gives 79 ppm Ca, and allows easy ratios of nutrient purchase. When we find unit weights for all 3, I suspect we may be able to use 7 or 8 ml of each to get very close to 0-8-16.
GM
exactlywatt
Active member
thanks for the advice lucas! i was thinking of feeding 1/3 strength but flushing every 6th watering or so, to leech the salts. do you have any opinions on using hydrogen peroxide when flushing?
also, i am thinking i should add some endomycorrhizal fungus in the metanaturals formula, but the plants on the GH formula shouldn't need this, correct?
also, i am thinking i should add some endomycorrhizal fungus in the metanaturals formula, but the plants on the GH formula shouldn't need this, correct?
gregor_mendel
Active member
hi exactlywatt
I am not Lucas, but would like to offer an answer.
Whether or not to add beneficial fungi should have nothing to do with the type of nutrient being used.
So if using fungi with metanaturals and promix is beneficial, then using fungi with GH and promix will be beneficial.
If you already have fungi, GH, MN, and promix, you could run four groups in one room to test this theory.
GM
I am not Lucas, but would like to offer an answer.
Whether or not to add beneficial fungi should have nothing to do with the type of nutrient being used.
So if using fungi with metanaturals and promix is beneficial, then using fungi with GH and promix will be beneficial.
If you already have fungi, GH, MN, and promix, you could run four groups in one room to test this theory.
GM
exactlywatt
Active member
hello gregor!
i just might run that very test... my assumption that GH doesn't need the fungi is based on my thinking that the chem nutes don't need to be processed in order for the plant to use them. and that the fungi feed on the organic nutes, break them down, and then in turn feed the plant; does this process still take place when using chem nutrients?
i just might run that very test... my assumption that GH doesn't need the fungi is based on my thinking that the chem nutes don't need to be processed in order for the plant to use them. and that the fungi feed on the organic nutes, break them down, and then in turn feed the plant; does this process still take place when using chem nutrients?
Longwind Mode ON
Longwind Mode ON
> The MN gets a value of 29 ppm Mg with no unit weight. We can assume it will also be higher when we weigh it (any volunteers?), but probably not the target of 60 ppm.
I share your "cultural bias" about the 60ppm target range for Mg, but, over time Ive come to notice that other styles of growing, medium based ones, use half that target
> My point is that in a constantly wet medium, 10A+10B may fall short on Mg
total agreement
please go ahead and take over the class from here.. Im on vacation
your rock!
> I realize that calcium is not on our list, but how do we know mj doesn't need it when we have been giving her so much with 0-8-16 (and roughly the same amount in Floranova Bloom) and she has been so happy?
again the cultural bias we share, from being DWC or EBB Flow, where there is essentially no nute accumulation, a constant flushing system
calcium is delivered to medium based plants, often handwatered, by the tap water that medium based growers tend to use.. this works pretty well within the 100-250ppm range of tap waters.. but is not consistent, depend how hard the water is..
> 5ml of metanaturals calcium per gallon gives 79 ppm Ca, and allows easy ratios of nutrient purchase. When we find unit weights for all 3, I suspect we may be able to use 7 or 8 ml of each to get very close to 0-8-16.
go for it! share what you learn
fwiw, disclaimer ahead, If Metanaturals is low in Ca, it will work better with tap.. I dont have the specs for Metanaturals, except for NPK, no Mg, Ca, Fe.. please post a label guaranteed analysis if you have it..
> do you have any opinions on using hydrogen peroxide when flushing?
I tend to be against flushing in DWC or EBBFlow, but I think it makes good sense with medium based grows. But I would not use peroxide. Im afraid of it. Its very strong in some properties.
Generally speaking, Im totally against additives, until after you hit a gram a watt with a basic proven recipe
> also, i am thinking i should add some endomycorrhizal fungus in the metanaturals formula, but the plants on the GH formula shouldn't need this, correct?
imvho, correct
otoh, disclaimer.. not having actually tested it, I dont know
it is possible, maybe even likely, that the symbiotic organisms would still find some consumable material in refined nutes, would excrete plant useful substances, and produce another measure of health..
> my assumption that GH doesn't need the fungi is based on my thinking that the chem nutes don't need to be processed in order for the plant to use them. and that the fungi feed on the organic nutes, break them down, and then in turn feed the plant
again in my very humble opinion, I think that is correct. otoh, there are many additives that are good, especially the ones from composted kelp.. I just would want to do the math on their NPK's.. some additives are very strong..
btw, I hit on another aspect of the "you cant measure organics with a salt meter"... Nitrogen, something that cannot be measured on an EC meter, is very prevalent in raw organics, and can cause severe burn, nute overdose, so I think it is correct in that sense, that you cant measure the Nitrogen in Organics, nor refined nutes, with an Electrical Conductivity Meter..
I think that all goes to the reason for the 4-4-2 name applied to TDS meters designed for hydroponic use with a .7 conversion factor.. but I digress
just want to say a huge thank you to all for the in depth conversation
Lucas Lovingit
Longwind Mode ON
> The MN gets a value of 29 ppm Mg with no unit weight. We can assume it will also be higher when we weigh it (any volunteers?), but probably not the target of 60 ppm.
I share your "cultural bias" about the 60ppm target range for Mg, but, over time Ive come to notice that other styles of growing, medium based ones, use half that target
> My point is that in a constantly wet medium, 10A+10B may fall short on Mg
total agreement
please go ahead and take over the class from here.. Im on vacation
your rock!
> I realize that calcium is not on our list, but how do we know mj doesn't need it when we have been giving her so much with 0-8-16 (and roughly the same amount in Floranova Bloom) and she has been so happy?
again the cultural bias we share, from being DWC or EBB Flow, where there is essentially no nute accumulation, a constant flushing system
calcium is delivered to medium based plants, often handwatered, by the tap water that medium based growers tend to use.. this works pretty well within the 100-250ppm range of tap waters.. but is not consistent, depend how hard the water is..
> 5ml of metanaturals calcium per gallon gives 79 ppm Ca, and allows easy ratios of nutrient purchase. When we find unit weights for all 3, I suspect we may be able to use 7 or 8 ml of each to get very close to 0-8-16.
go for it! share what you learn
fwiw, disclaimer ahead, If Metanaturals is low in Ca, it will work better with tap.. I dont have the specs for Metanaturals, except for NPK, no Mg, Ca, Fe.. please post a label guaranteed analysis if you have it..
> do you have any opinions on using hydrogen peroxide when flushing?
I tend to be against flushing in DWC or EBBFlow, but I think it makes good sense with medium based grows. But I would not use peroxide. Im afraid of it. Its very strong in some properties.
Generally speaking, Im totally against additives, until after you hit a gram a watt with a basic proven recipe
> also, i am thinking i should add some endomycorrhizal fungus in the metanaturals formula, but the plants on the GH formula shouldn't need this, correct?
imvho, correct
otoh, disclaimer.. not having actually tested it, I dont know
it is possible, maybe even likely, that the symbiotic organisms would still find some consumable material in refined nutes, would excrete plant useful substances, and produce another measure of health..
> my assumption that GH doesn't need the fungi is based on my thinking that the chem nutes don't need to be processed in order for the plant to use them. and that the fungi feed on the organic nutes, break them down, and then in turn feed the plant
again in my very humble opinion, I think that is correct. otoh, there are many additives that are good, especially the ones from composted kelp.. I just would want to do the math on their NPK's.. some additives are very strong..
btw, I hit on another aspect of the "you cant measure organics with a salt meter"... Nitrogen, something that cannot be measured on an EC meter, is very prevalent in raw organics, and can cause severe burn, nute overdose, so I think it is correct in that sense, that you cant measure the Nitrogen in Organics, nor refined nutes, with an Electrical Conductivity Meter..
I think that all goes to the reason for the 4-4-2 name applied to TDS meters designed for hydroponic use with a .7 conversion factor.. but I digress
just want to say a huge thank you to all for the in depth conversation
Lucas Lovingit
Last edited:
Magic Bean Grow
New member
Effect of pH on Optimum Nutrient Levels (and other questions)
Effect of pH on Optimum Nutrient Levels (and other questions)
Hi Lucas:
I am growing with a six bucket recirculating DWC system and wanted to run a few questions past you. I currently am using the GH 1-2-3 formula and adding epsom salt (1/8tsp per gal) and protekt at a pH of ~5.2. I attempt to keep the nutrients at a constant EC adding DI water and/or nutes as needed.
Do you have any thoughts on factoring in the target pH of the nutrient solution when calculating optimum nutrient levels. For example, I have noticed that the Mg requirements effectively increase when the pH is at 5.8 rather than, say, 5.2 (due to decreased absorption).
Since there is not one ideal pH that maximizes uptake of all nutrients, should nutrient ranges be based on pH? There used to be a graphic on OG that showed the optimum ranges, but not how quickily the absorption dropped off outside of that range. Do you have any sources of info?
Also, when calculating the EC of the nutrient solution, do the "mobile" nutrients need to be considered differently since the plants will more rapidly absorb them. I am thinking the "non-mobile" nutrients will impact the EC more with the passage of time. I am attempting to calculate the individual contribution to the EC from each of the salts.
Lastly, what is your opinion of managing the nutrient replacement rate based on the goal of determining the target nutrient concentration of the plants? I top off my resevoir daily and use the following rules:
EC goes up -> using more water than nutes -> lower target EC.
EC goes down -> using more nutes than water -> raise target EC.
Thanks for allowing me to "pick your brain" so to speak.
Regards,
M-B-G
Effect of pH on Optimum Nutrient Levels (and other questions)
Hi Lucas:
I am growing with a six bucket recirculating DWC system and wanted to run a few questions past you. I currently am using the GH 1-2-3 formula and adding epsom salt (1/8tsp per gal) and protekt at a pH of ~5.2. I attempt to keep the nutrients at a constant EC adding DI water and/or nutes as needed.
Do you have any thoughts on factoring in the target pH of the nutrient solution when calculating optimum nutrient levels. For example, I have noticed that the Mg requirements effectively increase when the pH is at 5.8 rather than, say, 5.2 (due to decreased absorption).
Since there is not one ideal pH that maximizes uptake of all nutrients, should nutrient ranges be based on pH? There used to be a graphic on OG that showed the optimum ranges, but not how quickily the absorption dropped off outside of that range. Do you have any sources of info?
Also, when calculating the EC of the nutrient solution, do the "mobile" nutrients need to be considered differently since the plants will more rapidly absorb them. I am thinking the "non-mobile" nutrients will impact the EC more with the passage of time. I am attempting to calculate the individual contribution to the EC from each of the salts.
Lastly, what is your opinion of managing the nutrient replacement rate based on the goal of determining the target nutrient concentration of the plants? I top off my resevoir daily and use the following rules:
EC goes up -> using more water than nutes -> lower target EC.
EC goes down -> using more nutes than water -> raise target EC.
Thanks for allowing me to "pick your brain" so to speak.
Regards,
M-B-G
Last edited:
Hello M-B-G,
here is a collection of pH charts:
http://www.angelfire.com/cantina/fourtwenty/articles/nutrientavailability.htm
here is whats left of a discussion on CW (google cache):
http://64.233.179.104/search?q=cach...te:cannabisworld.org&hl=de&gl=de&ct=clnk&cd=2
i'm sure Lucas has to say a few things regarding top off's and "no res change" strategies
mace
here is a collection of pH charts:
http://www.angelfire.com/cantina/fourtwenty/articles/nutrientavailability.htm
here is whats left of a discussion on CW (google cache):
http://64.233.179.104/search?q=cach...te:cannabisworld.org&hl=de&gl=de&ct=clnk&cd=2
i'm sure Lucas has to say a few things regarding top off's and "no res change" strategies
mace
dont blame me if it works, blame my gurus
dont blame me if it works, blame my gurus
> Do you have any thoughts on factoring in the target pH of the nutrient solution when calculating optimum nutrient levels.
I aim for a pH flux between 5.2 and 5.8 to provide absorption ranges
> For example, I have noticed that the Mg requirements effectively increase when the pH is at 5.8 rather than, say, 5.2 (due to decreased absorption).
really? how can you tell?
GH 1-2-3 is quite strong in Mg, even before you chose to add more as Epsom
but to answer your question, as I hear it, No, I dont increase the Mg level when using higher pH levels.. Instead I try to get the pH down so the Mg is more assimilable.
> Since there is not one ideal pH that maximizes uptake of all nutrients,
I agree
> should nutrient ranges be based on pH?
I dont think so, instead pH should be allowed to fluctuate in a range, so the various pH levels that optimize the absorption of the different nutes can be met.
> There used to be a graphic on OG that showed the optimum ranges, but not how quickily the absorption dropped off outside of that range. Do you have any sources of info?
my guru pH, the person, has those charts on his Cannastats website (I see mace beat me to it, thanks for the links)
> I am attempting to calculate the individual contribution to the EC from each of the salts.
that would require individual nute element testing
I have instead adopted the belief that the plants take what they need, and leave the rest (from a reasonably balanced nute supply)
btw, I no longer think of plants as eating and shitting.. they dont have alimentary canals, nor excretory canals. I see nutrients as catalists and electrical potentials that allow the plants primary function, photosynthesis, to produce organic material (plant tissues), that form the basis for the entire food chain for the rest of the non plant life on the planet.
Plants are primarily comprised of Carbon and Oxygen, neither of which are obtained from nutes, they are both gasses the plant captures from the atmosphere.
> what is your opinion of managing the nutrient replacement rate based on the goal of determining the target nutrient concentration of the plants?
total agreement, if what you mean is similar to the idea that one should alter the amount of water and nutes in the top off solution, in order to maintain the target EC over the varying growth rates of the lifecycle of the plant
if EC goes up, Increase the dilution, if EC goes down, increase the nute addback
btw, as to pH, for small changes without pH modifyiers, to lower it, increase EC, to raise it, lower the EC
thanks to mace for this text:
"Mr. Highway has an excellent thread on adding nutes to the top off water, in which he finds that using full strength 0-8-16 in the addback, maintains his TDS.
http://www.cannabisworld.org/vbport...&threadid=45115
My experience is different, in that an addback of 33% of original mix seems to be sufficient to achieve the same goal. But we use different numbers of gallons per watt.
In both cases, we share the target goal of maintaining TDS near the original value of a fresh res."
regarding automating the addback nute strength... I find that with more than 40 gallons of res per 1k, the addback strength falls below 100%, but at res sizes closer to 25gal per 1k, like highway and toad had, addbacks closer to 100% seem to keep EC close to target.
This leads to the realization that there is a per crop nutrient total requirement.
GrowGreen has been at the forefront of this concept, having developed the strategy of using a specific total amount of nutes per crop. In the case of PBPBloom, GG's research indicates a total of 20 ounces of PBPBloom per 1k of light, is sufficient for the life of a crop...
so ultimately, we begin to see that not only do we want to know how strong the mix should be, EC wise, at any given time, but also that there is a finite total minimum nute requirement for the life of the crop
and, since Mace mentioned res changes.. in my experience, it is not necessary to change the res every 2 weeks, or on some other interval, if the strategy of maintaining EC is used.
the tactic of dumping nutes and mixing a fresh res comes from the GH website, and is associate with topping off with water only, no nutes..
it is also true that it is possible to keep the same nutes res, constantly bumped with additional nutes to maintain EC, for more than one crop cycle
I adopted Highway's nute addback strategy as being superior to water addbacks. The first time I became aware of the advantages was when Brettshouse posted a 17 ounce yield from 450watts.
It seems plants grow better if they get a constant supply of nutes, instead of a strong mix at first, topped only with water, then dump the res.
It was obvious before res changes topped with water only, that the plants lagged approaching the 100% addback point, and showed renewed vigor from a fresh res (primarily from the Nitrogen).
So I think its good to provide an ongoing nute bump, instead of water topped only.. This approach assumes that if some nutes were depleted in the res, the addback will help provide more. Nitrogen is the most noticeable addback nute benefit.
I do not have any experience to support my previous belief that nutes will accumulate to toxic levels if the plant reservoir is not dumped out periodically during the crop life. I really dont think its necessary to dump a res that is properly maintained.
pH modifyers are more problematic, than unused nutes. It is easy to cause problems by using too much pH down, as when working with hard tap water. Some nutes have lower pH levels than others, and require less pH down... in fact PBP in RO needs pH UP, not down.. pH UP is not as toxic as pH down.. that is, +or- 100ppm of K is not harmful, but a similar swing in P can be.
In commercial tomato hydro farms, they have the ability to measure individual nutes elements, and add back only those that the plants actually extracted, but, because some nutes remain in solution, and others move into the plant, that is not an accurate way to calculate the plants needs..
instead, we find that there are many proven commercially available nutes mixes that will support the plants nutrient needs. iow, its not necessary to replace every nute the plant removes from solution, nor does the plant toxify its res by uptaking nutes.
btw, I feel grateful to be asked questions as if I were a guru, but Im not, Im just a student of other peoples successful strategies, and I try to share the common elements I find in the apparently different nutes recipes and res management strategies. The plants seem to tolerate quite a wide range of values for the individual nutes, as I get reports of great yields from both PBP and GH, even though they are quite different in P and Mg levels.. (though with the addition of CalMag, PBP approaches GH's Mg level)
I have great respect for the experience of the many posters in this thread. thanks for contributing your knowledge.
Lucas
dont blame me if it works, blame my gurus
> Do you have any thoughts on factoring in the target pH of the nutrient solution when calculating optimum nutrient levels.
I aim for a pH flux between 5.2 and 5.8 to provide absorption ranges
> For example, I have noticed that the Mg requirements effectively increase when the pH is at 5.8 rather than, say, 5.2 (due to decreased absorption).
really? how can you tell?
GH 1-2-3 is quite strong in Mg, even before you chose to add more as Epsom
but to answer your question, as I hear it, No, I dont increase the Mg level when using higher pH levels.. Instead I try to get the pH down so the Mg is more assimilable.
> Since there is not one ideal pH that maximizes uptake of all nutrients,
I agree
> should nutrient ranges be based on pH?
I dont think so, instead pH should be allowed to fluctuate in a range, so the various pH levels that optimize the absorption of the different nutes can be met.
> There used to be a graphic on OG that showed the optimum ranges, but not how quickily the absorption dropped off outside of that range. Do you have any sources of info?
my guru pH, the person, has those charts on his Cannastats website (I see mace beat me to it, thanks for the links)
> I am attempting to calculate the individual contribution to the EC from each of the salts.
that would require individual nute element testing
I have instead adopted the belief that the plants take what they need, and leave the rest (from a reasonably balanced nute supply)
btw, I no longer think of plants as eating and shitting.. they dont have alimentary canals, nor excretory canals. I see nutrients as catalists and electrical potentials that allow the plants primary function, photosynthesis, to produce organic material (plant tissues), that form the basis for the entire food chain for the rest of the non plant life on the planet.
Plants are primarily comprised of Carbon and Oxygen, neither of which are obtained from nutes, they are both gasses the plant captures from the atmosphere.
> what is your opinion of managing the nutrient replacement rate based on the goal of determining the target nutrient concentration of the plants?
total agreement, if what you mean is similar to the idea that one should alter the amount of water and nutes in the top off solution, in order to maintain the target EC over the varying growth rates of the lifecycle of the plant
if EC goes up, Increase the dilution, if EC goes down, increase the nute addback
btw, as to pH, for small changes without pH modifyiers, to lower it, increase EC, to raise it, lower the EC
thanks to mace for this text:
"Mr. Highway has an excellent thread on adding nutes to the top off water, in which he finds that using full strength 0-8-16 in the addback, maintains his TDS.
http://www.cannabisworld.org/vbport...&threadid=45115
My experience is different, in that an addback of 33% of original mix seems to be sufficient to achieve the same goal. But we use different numbers of gallons per watt.
In both cases, we share the target goal of maintaining TDS near the original value of a fresh res."
regarding automating the addback nute strength... I find that with more than 40 gallons of res per 1k, the addback strength falls below 100%, but at res sizes closer to 25gal per 1k, like highway and toad had, addbacks closer to 100% seem to keep EC close to target.
This leads to the realization that there is a per crop nutrient total requirement.
GrowGreen has been at the forefront of this concept, having developed the strategy of using a specific total amount of nutes per crop. In the case of PBPBloom, GG's research indicates a total of 20 ounces of PBPBloom per 1k of light, is sufficient for the life of a crop...
so ultimately, we begin to see that not only do we want to know how strong the mix should be, EC wise, at any given time, but also that there is a finite total minimum nute requirement for the life of the crop
and, since Mace mentioned res changes.. in my experience, it is not necessary to change the res every 2 weeks, or on some other interval, if the strategy of maintaining EC is used.
the tactic of dumping nutes and mixing a fresh res comes from the GH website, and is associate with topping off with water only, no nutes..
it is also true that it is possible to keep the same nutes res, constantly bumped with additional nutes to maintain EC, for more than one crop cycle
I adopted Highway's nute addback strategy as being superior to water addbacks. The first time I became aware of the advantages was when Brettshouse posted a 17 ounce yield from 450watts.
It seems plants grow better if they get a constant supply of nutes, instead of a strong mix at first, topped only with water, then dump the res.
It was obvious before res changes topped with water only, that the plants lagged approaching the 100% addback point, and showed renewed vigor from a fresh res (primarily from the Nitrogen).
So I think its good to provide an ongoing nute bump, instead of water topped only.. This approach assumes that if some nutes were depleted in the res, the addback will help provide more. Nitrogen is the most noticeable addback nute benefit.
I do not have any experience to support my previous belief that nutes will accumulate to toxic levels if the plant reservoir is not dumped out periodically during the crop life. I really dont think its necessary to dump a res that is properly maintained.
pH modifyers are more problematic, than unused nutes. It is easy to cause problems by using too much pH down, as when working with hard tap water. Some nutes have lower pH levels than others, and require less pH down... in fact PBP in RO needs pH UP, not down.. pH UP is not as toxic as pH down.. that is, +or- 100ppm of K is not harmful, but a similar swing in P can be.
In commercial tomato hydro farms, they have the ability to measure individual nutes elements, and add back only those that the plants actually extracted, but, because some nutes remain in solution, and others move into the plant, that is not an accurate way to calculate the plants needs..
instead, we find that there are many proven commercially available nutes mixes that will support the plants nutrient needs. iow, its not necessary to replace every nute the plant removes from solution, nor does the plant toxify its res by uptaking nutes.
btw, I feel grateful to be asked questions as if I were a guru, but Im not, Im just a student of other peoples successful strategies, and I try to share the common elements I find in the apparently different nutes recipes and res management strategies. The plants seem to tolerate quite a wide range of values for the individual nutes, as I get reports of great yields from both PBP and GH, even though they are quite different in P and Mg levels.. (though with the addition of CalMag, PBP approaches GH's Mg level)
I have great respect for the experience of the many posters in this thread. thanks for contributing your knowledge.
Lucas
Last edited:
G
Guest
Hi people. Thanks for all the great reading.
I'm trying to find some kind of 'hard formula' for nute addition myself.
I think in measuring what exactly the plants uptake in an organic based system I may need the following approach.
Elemental breakdown of what is used as nutrition (nutes & fish food & water)
Recorded data of the amounts and times anything is ever added.
Recorded data of everything that is ever subtracted (harvest, trimming, evaporation, transpiration)
Foliage tests to coincide with before and after system additions, and regular periods thereafter.
In seperating and categorising the content and atomic weight of nutrients and water content etc to enter the system I hope to have a clear record of inputs.
This will then be set against the outputs - evapotranspiration rates, dried weights of plant material, foliage content, fish growth, nutrient uptake of fish.
I hope that by subtracting the atomic weights of the outputs from the inputs I can get a 'reasonably' accurate picture of what is being utilised in my system.
These tests will be taken in an environment with climate control so the temperature ranges remain constant daily in both reservoir and room.
I'm aware there are many other factors, and hope you may be able to help determine a correct (thorough) method before I spend 2 years and stupid amounts of cash and time with test equipment.
Factors to consider - strain variation, lighting amounts, spectrum and periods. Temperatures, pH, kH GH, DH.
My large bio-filter also creates measureable (so it's said) amounts of CO2 and nitrous oxide. These too, will have impact on my 'ecosystem' as a whole.
Any thoughts, suggestions?
Test equipment expenses will only be expended when I'm clear of how to acquire good relevant data, and when I have my greenhouse completed in 4 months. According to plan (crosses fingers and legs).
I'm trying to find some kind of 'hard formula' for nute addition myself.
I think in measuring what exactly the plants uptake in an organic based system I may need the following approach.
Elemental breakdown of what is used as nutrition (nutes & fish food & water)
Recorded data of the amounts and times anything is ever added.
Recorded data of everything that is ever subtracted (harvest, trimming, evaporation, transpiration)
Foliage tests to coincide with before and after system additions, and regular periods thereafter.
In seperating and categorising the content and atomic weight of nutrients and water content etc to enter the system I hope to have a clear record of inputs.
This will then be set against the outputs - evapotranspiration rates, dried weights of plant material, foliage content, fish growth, nutrient uptake of fish.
I hope that by subtracting the atomic weights of the outputs from the inputs I can get a 'reasonably' accurate picture of what is being utilised in my system.
These tests will be taken in an environment with climate control so the temperature ranges remain constant daily in both reservoir and room.
I'm aware there are many other factors, and hope you may be able to help determine a correct (thorough) method before I spend 2 years and stupid amounts of cash and time with test equipment.
Factors to consider - strain variation, lighting amounts, spectrum and periods. Temperatures, pH, kH GH, DH.
My large bio-filter also creates measureable (so it's said) amounts of CO2 and nitrous oxide. These too, will have impact on my 'ecosystem' as a whole.
Any thoughts, suggestions?
Test equipment expenses will only be expended when I'm clear of how to acquire good relevant data, and when I have my greenhouse completed in 4 months. According to plan (crosses fingers and legs).
exactlywatt
Active member
lucas here are those metanaturals 3-3-3 specs:
Mg 0.50%
Cu 0.050%
Fe 0.10%
Mn 0.050%
Mo 0.0005%
Zn 0.10%
Humic Acids 0.2%
citric acid is used for chelating
the 3-3-3 has no calcium at at all, they sell a calcium supplement that has 6% calcium and some Mn and humic acids. the 1-5-5 has no micronutrients (except .5% Mg) and no calcium either.
as you said before, as i grow in a medium i do use tap water, and my tap water has plenty of calcium...
Mg 0.50%
Cu 0.050%
Fe 0.10%
Mn 0.050%
Mo 0.0005%
Zn 0.10%
Humic Acids 0.2%
citric acid is used for chelating
the 3-3-3 has no calcium at at all, they sell a calcium supplement that has 6% calcium and some Mn and humic acids. the 1-5-5 has no micronutrients (except .5% Mg) and no calcium either.
as you said before, as i grow in a medium i do use tap water, and my tap water has plenty of calcium...
exactlywatt
Active member
lucas, i've read in the past that you suggest adding 1/4 tsp epsom to the metanaturals formula, or any other organic formulas for that matter, but i haven't seen that advice given in this thread. do you still recommend adding the epsom?
here's a link to some more organic formulas that lucas came up with...
http://www.icmag.com/ic/showthread.php?t=7253
here's a link to some more organic formulas that lucas came up with...
http://www.icmag.com/ic/showthread.php?t=7253
Here is the Mg level of GH 8micro 16bloom
Mg 63
I use 60ppm of Mg as my target for DWC and EFlow, but often see half that value in nutes designed for medium.
As you point out above here are the spreadsheet results of Metanaturals Mg level after inputting the specs you posted, thanks! (unweighted liquids)
Mg 26
Here is the Mg level of 15PBP plus 5cal mag
Mg 36
Here is the Mg level of 1/4 teaspoon of epsom salt
Mg 31
In the past I assumed everyone should add Epsom, to bring up the Mg, but folks in medium grow healthy plants at the lower Mg levels.. I think it accumulates in the medium..
So for Metanaturals or PBP in DWC or EFlow, I do recommend 1/4 tsp epsom per gallon, but for denser mediums like potting mix, Coco, sunshine, etc, I dont think the extra Mg is needed.
In terms of Mg % on labels, GH Flora Bloom runs at 1.5%, Flora Nova Bloom runs at 2% spec. PBP runs at .5%, and Cal Mag has 1.2%, which in combination yields .9%, the Metanaturals spec is 1% combined.
In my limited experience, 1.5 to 2% Mg levels do not produce Mg deficiency in DWC EFlow bloom at the dosage levels of nutes I recommend targetting 60ppm
But, there are people who know a lot more about nutes than I do, that design nutes with much lower Mg levels. I dont know why, but, when used in Medium, they work. In DWC, they dont.
Canna Aqua runs at 2.2% Mg, Canna Coco runs at 1% Mg..
Young plants in veg dont seem to demonstrate Mg def at the 30-45ppm Mg levels, but when put to bloom they do, unless Mg is raised above 60.
Mg is toxic/excessive at 120ppm, at my best guesstimation. N is toxic above 400ppm, P above 200, and K above 400
pay it forward
Lucas
Mg 63
I use 60ppm of Mg as my target for DWC and EFlow, but often see half that value in nutes designed for medium.
As you point out above here are the spreadsheet results of Metanaturals Mg level after inputting the specs you posted, thanks! (unweighted liquids)
Mg 26
Here is the Mg level of 15PBP plus 5cal mag
Mg 36
Here is the Mg level of 1/4 teaspoon of epsom salt
Mg 31
In the past I assumed everyone should add Epsom, to bring up the Mg, but folks in medium grow healthy plants at the lower Mg levels.. I think it accumulates in the medium..
So for Metanaturals or PBP in DWC or EFlow, I do recommend 1/4 tsp epsom per gallon, but for denser mediums like potting mix, Coco, sunshine, etc, I dont think the extra Mg is needed.
In terms of Mg % on labels, GH Flora Bloom runs at 1.5%, Flora Nova Bloom runs at 2% spec. PBP runs at .5%, and Cal Mag has 1.2%, which in combination yields .9%, the Metanaturals spec is 1% combined.
In my limited experience, 1.5 to 2% Mg levels do not produce Mg deficiency in DWC EFlow bloom at the dosage levels of nutes I recommend targetting 60ppm
But, there are people who know a lot more about nutes than I do, that design nutes with much lower Mg levels. I dont know why, but, when used in Medium, they work. In DWC, they dont.
Canna Aqua runs at 2.2% Mg, Canna Coco runs at 1% Mg..
Young plants in veg dont seem to demonstrate Mg def at the 30-45ppm Mg levels, but when put to bloom they do, unless Mg is raised above 60.
Mg is toxic/excessive at 120ppm, at my best guesstimation. N is toxic above 400ppm, P above 200, and K above 400
pay it forward
Lucas
Lucas;
I've noticed a degree of N deficiency, when I allow my aero setup tds levels to climb from 900 to 1050 (.5 conversion), before adding back makeup water and nutrients. If one were to utilize your 1/3 addback regimen, via an automatic float valve, would the small amount of N being fed in, to replace the water/nutes that have been consumed, alleviate or minimize the signs of N deficiency? I realize that N is the most mobile element, the plants will pig out on any that is available, and store it in the large fan leaves, then pull it out, when the supply (reservoir) is depleted of N. I believe that is what I'm seeing, as an N deficiency, in that it is primarily the larger, and lower, fan leaves that are showing signs, not the top of the plant, where the new growth is taking place.
DD
I've noticed a degree of N deficiency, when I allow my aero setup tds levels to climb from 900 to 1050 (.5 conversion), before adding back makeup water and nutrients. If one were to utilize your 1/3 addback regimen, via an automatic float valve, would the small amount of N being fed in, to replace the water/nutes that have been consumed, alleviate or minimize the signs of N deficiency? I realize that N is the most mobile element, the plants will pig out on any that is available, and store it in the large fan leaves, then pull it out, when the supply (reservoir) is depleted of N. I believe that is what I'm seeing, as an N deficiency, in that it is primarily the larger, and lower, fan leaves that are showing signs, not the top of the plant, where the new growth is taking place.
DD
Hi DandyDon
good to see you
> I've noticed a degree of N deficiency, when I allow my aero setup tds levels to climb from 900 to 1050 (.5 conversion), before adding back makeup water and nutrients.
the TDS and pH of a partially depleted, unrefilled res is not relevant.
what is the TDS when you have the missing water added back?
how much % addback does this occur at..
iow, if you had a 20 gallon res, does this problem start after you have added 5 (25%), 10(50%), 15(75%), or 20(100%) gallons back?
I used to see a growth lag, at about 75% addback.
> If one were to utilize your 1/3 addback regimen, via an automatic float valve, would the small amount of N being fed in, to replace the water/nutes that have been consumed, alleviate or minimize the signs of N deficiency?
YES!
that is what I like about addback nutes, they provide ongoing N
whether 33% dilution addback is required depends on your res to watts ratio. Use whatever dilution strength brings your TDS back to 900 on a full res
> it is primarily the larger, and lower, fan leaves that are showing signs,
what signs are you using to diagnose N deficiency?
my symptom was stalled growth, followed by greening of the entire plant, and more vigorous growth rate, after a fresh res change, when I was only topping with nutes until 100% addback.
hth
Lucas
good to see you
> I've noticed a degree of N deficiency, when I allow my aero setup tds levels to climb from 900 to 1050 (.5 conversion), before adding back makeup water and nutrients.
the TDS and pH of a partially depleted, unrefilled res is not relevant.
what is the TDS when you have the missing water added back?
how much % addback does this occur at..
iow, if you had a 20 gallon res, does this problem start after you have added 5 (25%), 10(50%), 15(75%), or 20(100%) gallons back?
I used to see a growth lag, at about 75% addback.
> If one were to utilize your 1/3 addback regimen, via an automatic float valve, would the small amount of N being fed in, to replace the water/nutes that have been consumed, alleviate or minimize the signs of N deficiency?
YES!
that is what I like about addback nutes, they provide ongoing N
whether 33% dilution addback is required depends on your res to watts ratio. Use whatever dilution strength brings your TDS back to 900 on a full res
> it is primarily the larger, and lower, fan leaves that are showing signs,
what signs are you using to diagnose N deficiency?
my symptom was stalled growth, followed by greening of the entire plant, and more vigorous growth rate, after a fresh res change, when I was only topping with nutes until 100% addback.
hth
Lucas
Hi Lucas;
Good to visit with you again, I miss "the old days".
>what is the TDS when you have the missing water added back?
To be honest, I don't know, as I've been adding back 1/3 strength nutes, 5 gallons at a time, to bring the res back to about 15 gallons. With this addback, the tds drops back to 900 ppm (.5 conversion)
>iow, if you had a 20 gallon res, does this problem start after you have added 5 (25%), 10(50%), 15(75%), or 20(100%) gallons back?
I guess it would either be 75% or 100%, since I last dumped the res and started afresh.
>I used to see a growth lag, at about 75% addback.
That's about where I'm seeing the same thing, maybe one more addback (100%)
>whether 33% dilution addback is required depends on your res to watts ratio.
20 gallon reservoir, which I fill to 3/4, or 15 gallons (small leak on my sight tube, so I can't fill to max), under a 600 Eye.
>Use whatever dilution strength brings your TDS back to 900 on a full res
The 1/3 strength addback (FNB) does this nicely, bringing it back from 1050 to 900 +/- 20 points.
>what signs are you using to diagnose N deficiency?
Yellowing of the lower leaves, eventually dieing off, whereas the top growth is still doing well. My guess is that the plant is cannabilizing the stored N in the lower leaves. I don't think it's from a lack of light, as most of those that die off were well lit. Plants (DPxSkunk) were trimmed to 6 branches early on.
>my symptom was stalled growth, followed by greening of the entire plant, and more vigorous growth rate, after a fresh res change, when I was only topping with nutes until 100% addback.
Now we're talking, I was wondering if it would be beneficial to just dump the whole res, and start afresh, but didn't want to do that, until I'd had a chance to query you, or be advised by you, to do so. Guess I'll be doing that, when I get up (night shift can be a real bitch).
I can't set up the aero unit with a float valve, can't get one into the barrel I use for a res, but I'm also setting up a 15 gallon dwc scrog unit, under a new 400 (8 sq. ft. scrog), where I have a float valve set in place, with an air injected powerhead. That will be the real test of the automatic addback, to see if the foliage remains healthy, from beginning to end.
Thanks for the advice, again, it does help
DD
Good to visit with you again, I miss "the old days".
>what is the TDS when you have the missing water added back?
To be honest, I don't know, as I've been adding back 1/3 strength nutes, 5 gallons at a time, to bring the res back to about 15 gallons. With this addback, the tds drops back to 900 ppm (.5 conversion)
>iow, if you had a 20 gallon res, does this problem start after you have added 5 (25%), 10(50%), 15(75%), or 20(100%) gallons back?
I guess it would either be 75% or 100%, since I last dumped the res and started afresh.
>I used to see a growth lag, at about 75% addback.
That's about where I'm seeing the same thing, maybe one more addback (100%)
>whether 33% dilution addback is required depends on your res to watts ratio.
20 gallon reservoir, which I fill to 3/4, or 15 gallons (small leak on my sight tube, so I can't fill to max), under a 600 Eye.
>Use whatever dilution strength brings your TDS back to 900 on a full res
The 1/3 strength addback (FNB) does this nicely, bringing it back from 1050 to 900 +/- 20 points.
>what signs are you using to diagnose N deficiency?
Yellowing of the lower leaves, eventually dieing off, whereas the top growth is still doing well. My guess is that the plant is cannabilizing the stored N in the lower leaves. I don't think it's from a lack of light, as most of those that die off were well lit. Plants (DPxSkunk) were trimmed to 6 branches early on.
>my symptom was stalled growth, followed by greening of the entire plant, and more vigorous growth rate, after a fresh res change, when I was only topping with nutes until 100% addback.
Now we're talking, I was wondering if it would be beneficial to just dump the whole res, and start afresh, but didn't want to do that, until I'd had a chance to query you, or be advised by you, to do so. Guess I'll be doing that, when I get up (night shift can be a real bitch).
I can't set up the aero unit with a float valve, can't get one into the barrel I use for a res, but I'm also setting up a 15 gallon dwc scrog unit, under a new 400 (8 sq. ft. scrog), where I have a float valve set in place, with an air injected powerhead. That will be the real test of the automatic addback, to see if the foliage remains healthy, from beginning to end.
Thanks for the advice, again, it does help
DD
exactlywatt
Active member
hey all, i just bought all the gear to run a Metanaturals vs. GH in a soiless medium comparison. beans go into water tonight! and my vaportek just got here as i'm typing this, fuckin' cool!!!!
gregor_mendel
Active member
Hi exactlywatt
I am excited that you are doing a side by side with these two sets of nutes. Do your Metanaturals nutes have the weight on the label?
If not, could you weigh as large a volume of each nute as you have the scale capability for, and post it?
I would do this myself, but my metanaturals is old, and I am afraid it would not be reliable.
Using no weight at all, 10mL each of the 1-5-5 and 3-3-3 give very near the same elemental ppm values as GH with no weight given. Being that the MN is in humic acid, I am sure it weighs more than GH. If we have this weight, we can nail down an exact formula (might be 10 mL of each) for the good of the community.
GM
I am excited that you are doing a side by side with these two sets of nutes. Do your Metanaturals nutes have the weight on the label?
If not, could you weigh as large a volume of each nute as you have the scale capability for, and post it?
I would do this myself, but my metanaturals is old, and I am afraid it would not be reliable.
Using no weight at all, 10mL each of the 1-5-5 and 3-3-3 give very near the same elemental ppm values as GH with no weight given. Being that the MN is in humic acid, I am sure it weighs more than GH. If we have this weight, we can nail down an exact formula (might be 10 mL of each) for the good of the community.
GM
exactlywatt
Active member
gregor-
i plead ignorance in weighing nutes, what kind of scale do i need? i've always been a humble dirt grower, no need for equipment...
if you've stored your metanaturals in a cool dark place then don't worry about it being "old". compost just ferments and keeps on going... go ahead and weigh it and see what #'s you get.
i plead ignorance in weighing nutes, what kind of scale do i need? i've always been a humble dirt grower, no need for equipment...
if you've stored your metanaturals in a cool dark place then don't worry about it being "old". compost just ferments and keeps on going... go ahead and weigh it and see what #'s you get.
