Need Information on Cal/Mag Deficiencies When Using Led Lights

Greengenes707 said:

As for @CobKits issue...it's that recipe of yours/jorge's. Ratios are off, strengths are off. You should really take a look at commercial greenhouse formulas as well as break down commonly used store bought recipes and see what is actually needed.

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ill break down the veg and flower formulas i got going when i get a chance, would love to hear your opinions. i got lazy after 20 years of GH but fuck monsanto.

After skimming through I did not see the answer. Here is what I have found.

https://www.blackdogled.com/lst

Leaf surface temperature,
If you are using spectrum specific lighting like LED the leaf has a lower temperature in itself, in turn lowering the transpiration rate. Calcium is immobile or "passive" and requires transpiration to be brought to new growth. Lack of transpiration = Lack of immobile nutrients I.E calcium.

When using LEDs that have Nanometer specific diodes you must bring ambient temperatures up and/or lower the Rh% to open stomata more to increase transpiration.

An easy fix is to slowly lower your LED lights as the emitted light will raise relative temperatures. In my experience standard 70-75° isn't enough even for 5w diodes. My 135W Draw 5w diode LED panel is about 6" from the tops when winter hits and raising temps is a pain or simply improbable. Leaves like to sit at 80° LST and if your ambient temps are below that and your LED doesn't emit much heat you will have slowed transpiration. It can cause a plethora of problems and usually just ugly leaves.

If you have problems raising ambient temperatures switch to an HPS kit for 160$ on Amazon. Similar price to decent LED's.

Do not underestimate Leaf Surface Temperature as I believe but have not proven that it is the cause of "Leaf Tacos" and "Light Bleaching" not just that your "Lights are too close"
This is why some can get away with 600w hps 6" from the tops and others have issues passing a 16" barrier.

Plants loaded with silica will not droop the same nor will it taco in an attempt to slow transpiration as the cell walls have a phenomenal vigor to keep leaves in a photosynthesis promoting position.

Late to the part but started getting rust/orange spots on my 4 week old bitch. Ask around and came down to cal, mag or I think phosphorus. I decided to let ot go since I know each individual ppm of my mix and that was a week ago. It has started to spread on to more leafs. I started to wonder about my lights being to close but besides only being the canopy that is effect nothig else.

Then I remembered hearing about mag deficiency brought on by led lights. Some people say bullshit and others say they have tested it and found it to be true. Did some online research for a little bit and came back from with this from a topline led fixture maker for there own lights, highend cob or strip.

Sometimes magnesium deficiencies are reported when making the switch to LED’s. This is because magnesium is a central element in the production of chlorophyll. When we make the move to LED’s, a more chlorophyll targeted spectrum is part of the benefits. As well as overall higher photosynthetic activity. But in order to reap those benefits, we need to match the elemental requirements of the increased chlorophyll focused reactions taking place.

Common hydroponic fertilizers recipes, usually contain between 40-60ppm Mg. We have found that a range or 75-90ppm of Mg to ideal under LED lighting. The best way to increase only Mg and not introduce more nitrogen, is to add 1gram of epsom salt(Magnesium Sulfate) per gallon of nutrient solution. 1gram/gallon of epsom salt adds ~25ppm of Mg and 30ppm of S, and is usually a sufficient supplement to most fertilizer programs.

shawnery said:

Late to the part but started getting rust/orange spots on my 4 week old bitch. Ask around and came down to cal, mag or I think phosphorus. I decided to let ot go since I know each individual ppm of my mix and that was a week ago. It has started to spread on to more leafs. I started to wonder about my lights being to close but besides only being the canopy that is effect nothig else.

Then I remembered hearing about mag deficiency brought on by led lights. Some people say bullshit and others say they have tested it and found it to be true. Did some online research for a little bit and came back from with this from a topline led fixture maker for there own lights, highend cob or strip.

Sometimes magnesium deficiencies are reported when making the switch to LED’s. This is because magnesium is a central element in the production of chlorophyll. When we make the move to LED’s, a more chlorophyll targeted spectrum is part of the benefits. As well as overall higher photosynthetic activity. But in order to reap those benefits, we need to match the elemental requirements of the increased chlorophyll focused reactions taking place.

Common hydroponic fertilizers recipes, usually contain between 40-60ppm Mg. We have found that a range or 75-90ppm of Mg to ideal under LED lighting. The best way to increase only Mg and not introduce more nitrogen, is to add 1gram of epsom salt(Magnesium Sulfate) per gallon of nutrient solution. 1gram/gallon of epsom salt adds ~25ppm of Mg and 30ppm of S, and is usually a sufficient supplement to most fertilizer programs.

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You can also try bringing up the temprature ever so slightly.

Rocket Soul said:

You can also try bringing up the temprature ever so slightly.

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Increase internal leaf temps because LEDs have no IR light while hps does. Next grow I'm going to attempt this with 9 degree temp increase.

Your idea, based on any data, is the lack of leaf temp or something else?

shawnery said:

Increase internal leaf temps because LEDs have no IR light while hps does. Next grow I'm going to attempt this with 9 degree temp increase.

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I wouldnt go for decided values but let your plant work it out. Its sort of a balancing act between getting to that vpd that works best for your plants in the moment, together with how strong nutes you wanna run. The more you increase vpd (raise temp and lower humidity) the more water the plant will transpire, the more nutrients it will have just due to going thru more water per day. This up to a point, when the plant closes the stomata to retain water, lazy plant stances and heat signs will tell you when you get there.

shawnery said:

Increase internal leaf temps because LEDs have no IR light while hps does. Next grow I'm going to attempt this with 9 degree temp increase.

Your idea, based on any data, is the lack of leaf temp or something else?

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We tried raising heat when the plants started giving diverse signs of deficiencies (purple stems etc), just looking generally unhappy. The raised temps got water and nutes flowing thru increased transpiration and better metabolic rate. Worked both in veg and flower (with cmh though, but its also a much colder light than standard hps). Infact the plants wouldnt take more than 10000lux in veg without starting to display sign of unhappiness or bleaching. One gas heater was all it took to get things running smoothly.

But i cant say im an expert enough to give exact advice, its more about having the whole equation in your head: heat/humdity regulates the flow of water and nutes thru your plant. You control the nute rates in the res and light intensity (which you wanna have as high as your plants can take in flower).
If you have signs of deficiencies: whats easiest to change in order to have more nutes in your plants without affecting basic limits of growing? You can bring up the heat and have the plant consume more water (and thus more nutes) but youll have more humidity. You could pull the light away slightly but you will have less buds. You could lower humidity but you would be limited by how much your dehum can take, and how much it raises the temp and getting vpd so far out of wack that they close stomata. Or by your outside condition if your vented. Or you can up mag in the res, but you might run into a situation where you overdose or simply cannot get up mag enough without burning tips, or having to much N from adding extra CalcNitrate.

Its just a tool for you to evaluate which way is gets you where you want easiest.

The rest is dialing in and fine tuning. One way of doing it is simply set your temps to where you want them, around 26-28°C for leds, and play with raising and lowering humidity and youll yee where they are praying and get a hold of the intervall. The higher the temp the more narrow is the interval of ok humdity.

If anything with LEDs I think most people use too much calcium.
HID gives nice bright spots right under the bulb, but to the best of my knowledge a dialed in LED system is going to have higher levels spread more evenly through the canopy and therefore lead to higher transpiration. Calcium being passively taken up can start becoming a problem. It has a double positive bond so it really binds to shit quite easily

I have found many sources, not people spouting I believe, that state with good reasoning and experience that 50% more magnesium not calcium.

CobKits said:

in my opinion its a myth

more than likely people not adapting to the higher usable ppfd and its just common to get deficiencies. Calmag is a great product but now that im using jacks i have 100 ppm ca and 80 ppm mg from the nutes alone, no epsom salts or supplemental calcium for me

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It's 100% not a myth, I tried the old 1st Gen Vipar and without calcium supplemented in flower the plant turned twisted, retarded and looked like some weird crazy plant that never recovered. lesson learned

any calmag issues i had with LEDs were solved using the same old nute formulations and increasing air temp

Well, I do agree with some information here but let's look at the chlorophyll A molecule.

The molecular structure of chlorophyll aconsists of a chlorin ring, whose four nitrogen atoms surround a central magnesium atom, and has several other attached side chains and a hydrocarbon tail.

If LED's truly raise photosynthetic activity to a point that the plant cannot upkeep chlorophyll synthesis we would see nitrogen stolen from the bottom leaves first as chlorophyll A has 4 times the nitrogen molecules as it does magnesium molecules.

What I do believe is that the plant actually requires less calmag as the photorespiration reduces under lights that do not raise internal leaf temperatures from "wasted" light. (LED's) and regularly adding calmag results in a lockout.
Raising ambient temperatures can work but doing research on a plants ability to efficiently use nutrients under a high transpiration rate isn't an effective use of nutrients and lies under the category of wasteful practices.

Take it easy and watch for any spreading symptoms, a lot of things in a grow room could be very short lived and resolved without excess interventions.

Through my research I've found that the probability of finding yourself with cal or mag toxicity is very nill. I'll let you know if increasing my mag by 50% stops the spread of my mag deficiency.

I've been thinking about this very intensely for the last couple days and have beem considering the temp argument and it doesn't make sense on a lamens level.

My deficiency is only effecting the leaves that are directly in the line of led fire, so to say. Any and all leaves below the canopy are showing no symptoms of a deficiency at all. If it was do to leaf temps then the deficiency, at least in my understanding, would show in some level on all leaves but it's not at all.

If it was a leaf temp thing and not something else, perhaps wavelength, wouldn't affect all leaves on some level?

Here's my canopy and everything below it is fine. My LEDs make them appear much more yellow than they are as well.

5th week of flower.

shawnery said:

I've been thinking about this very intensely for the last couple days and have beem considering the temp argument and it doesn't make sense on a lamens level.

My deficiency is only effecting the leaves that are directly in the line of led fire, so to say. Any and all leaves below the canopy are showing no symptoms of a deficiency at all. If it was do to leaf temps then the deficiency, at least in my understanding, would show in some level on all leaves but it's not at all.

If it was a leaf temp thing and not something else, perhaps wavelength, wouldn't affect all leaves on some level?

Here's my canopy and everything below it is fine. My LEDs make them appear much more yellow than they are as well.

5th week of flower.

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I’m no expert by any means, but some deficiencies progress from the top down. Some progress from the bottom up. Some just kind of pop up where they pop up.

EDIT: Directly quoting my resource: immobile nutrients show deficiency/excess on new leaves. The opposite is true for mobile nutrients.

This is why I'm back to this being specifically cause by the LED light that I'm using which are top-of-the-line self-built.

Not only is it only showing on the canopy but the canopy is not just New Growth it's new and old. It showed first on the bigger older leaves in the canopy and is slowly progressing through the smaller leaves. Yet it still has not gone below the canopy whatsoever.

i've never been able to rectify these cal/mag deficiencies with led, had to put plants back under cmh or led.
adding cal/mag does nothing as isn't this just nute lockout due to what ever reason be it to cold or insufficient spectrum.

shawnery said:

Through my research I've found that the probability of finding yourself with cal or mag toxicity is very nill. I'll let you know if increasing my mag by 50% stops the spread of my mag deficiency.

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ANC didn't say toxicity he said lockout. You can lockout another ion by filling the receptor site it would normally bind to and it wouldn't necessarily produce toxicity. So that is a possibility.

The heat factor is also another possibility as LED runs a lot cooler than HIDs. From my own anecdotal experience my plants easily put up with more heat than less. My canopy runs at 105 for extended periods of time during the summer. I also run at extremely low humidity, 10% without issue. I get excellent yields and have to feed a bit heavier.

Right now since I'm not supplementing with heat we've slowed down considerably under equivalent light. I would speculate that different temps would produce different uptake of nutrients ie not all nutrients are available at all temps and your leaf temps matter quite a bit, analogous to pH.

I don't have an answer but I think some excellent ideas are being looked at.

shawnery said:

This is why I'm back to this being specifically cause by the LED light that I'm using which are top-of-the-line self-built.

Not only is it only showing on the canopy but the canopy is not just New Growth it's new and old. It showed first on the bigger older leaves in the canopy and is slowly progressing through the smaller leaves. Yet it still has not gone below the canopy whatsoever.

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You could easily up your heat, for a week and see if that fixes things. If you have two rooms you could divide your plants and up the heat in one and change the nutrients ratios in another. I'd love to hear your experience with that.

coreywebster said:

Not looked further than this post but sounds like to much light.

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35,000lum and I tried raising with no change. If anything closer for more heat would seem to support the argument.

I'm gping to try upping my mag to 80 and see what happens, 80 isn't that high even.