Do LED’s promote cal-mag issues

Prawn Connery said:

Why would you use a blend that you know is deficient? That just doesn't make any sense.

Click to expand...

Each plant is diferent in its needs.and its a 3 part nute base with pure magnesium and pure calcium soo you can mix how you want.original recepie(on the box) is for tomatoes

OK, that makes a bit more sense if you've not used it before and don't have a formula. Indicas tend to be more magnesium hogs and prefer a slightly higher pH than sativas, so nutrient requirements can also be strain dependent, but generally a good alround nutrient has most things covered.

I'm a bit late to the party but thought it might help someone else. There's some very knowledgeable people commenting before me.

I'm running a HLG 650R in a 3x3 tent and have been fighting calcium def problems for 3 years. I thought it was because my fertilizer had too much ammoniacal nitrogen and about 10 other things, but recently discovered that it was primarily not enough transpiration. I was running hot enough but I had to significantly lower humidity to solve the problem. Now I can run on full power and keep the plants green.

Now I keep the humidity under 60% measured within the canopy. I've been listening to Bruce Bugbee preach under 60% for a while but blindly followed the VPD charts until I heard him say it again this year and it finally sunk in.

egregory6 said:

I'm a bit late to the party but thought it might help someone else. There's some very knowledgeable people commenting before me.

I'm running a HLG 650R in a 3x3 tent and have been fighting calcium def problems for 3 years. I thought it was because my fertilizer had too much ammoniacal nitrogen and about 10 other things, but recently discovered that it was primarily not enough transpiration. I was running hot enough but I had to significantly lower humidity to solve the problem. Now I can run on full power and keep the plants green.

Now I keep the humidity under 60% measured within the canopy. I've been listening to Bruce Bugbee preach under 60% for a while but blindly followed the VPD charts until I heard him say it again this year and it finally sunk in.

Click to expand...

Growth stage? Air temp?

egregory6 said:

I'm a bit late to the party but thought it might help someone else. There's some very knowledgeable people commenting before me.

I'm running a HLG 650R in a 3x3 tent and have been fighting calcium def problems for 3 years. I thought it was because my fertilizer had too much ammoniacal nitrogen and about 10 other things, but recently discovered that it was primarily not enough transpiration. I was running hot enough but I had to significantly lower humidity to solve the problem. Now I can run on full power and keep the plants green.

Now I keep the humidity under 60% measured within the canopy. I've been listening to Bruce Bugbee preach under 60% for a while but blindly followed the VPD charts until I heard him say it again this year and it finally sunk in.

Click to expand...

A hlg650r in a 3x3? That's a lot of watts for that footprint. I thought my 480 watt in a 3x3 was a lil too much. Have you run it full blast?

Yeah I run a total of 500 watts in a 3x5 (HLG350R + a 150 watt HLG DIY fixture). Which is ~33 watts/sq.ft.

650 watts in a 3x3 is ~72 watts/sq.ft.

You probably never need to run higher than 50% power in that setup

Here's a little more detail on my HLG 650R in a 3x3 tent:

For veg until 2 wks before 12/12, I run at 28-29° C and 60% humidity. Humidity goes to about 55% prior to 12/12 but is measured with the probe slightly within the top leaves. You want to monitor what the plant is feeling. Probes not in the canopy register much lower levels. 2 wks before 12/12 the temp steadily drops to 20 22° C at 2° per wk.

I'm in week 7 now at 30" above plant and at 535 watts and the plants are very happy. I usually grow 1 or 2 plants and veg 8 wks but these plants were in the cold & under a small light for the first 5 wks and are much smaller than usual. They are growing quickly now. I have back problems so fewer plants is easier for me.

For flower I try to get to full power at about 22 inches but it depends on the strain and how healthy they are. I get a little bleaching but I'm more concerned with getting max photons deeper into canopy and am willing to sacrifice a 1/4 inch of the center flowers to achieve that. I smoke the white tips and they seem fine to me. Sometimes I have to turn down the light but can usually keep it at full or close to full power.

I don't supplement CO2 but ambient in my basement in winter is over 800 ppm most of the time so I have a little bump there. I have five 6" non-oscillating fans in my tent to ensure that no leaf is robbed of air exchange. 4 on top and 1 on bottom. I will add a sixth one on the bottom soon. Just strong enough to not have wind-burn. This helps with nutrient (calcium) uptake. I also foliar spray calcium chloride twice a week or so. I avoid calcium nitrate foliar because the N can promote growth increasing the demand for calcium.

Current fertilizer is Jack's 5-12-26 with calcium nitrate. I often mix my own using Hydrobuddy. At week 7 of veg I'm at an EC of 1.8 fed 5 times per day. I try to run with only nitrate nitrogen but if runoff pH goes high, I'll use a little ammoniacal nitrogen. This run I mixed a little Sulphur into my 70/30 coco/perlite mix to keep ph low and it seems to be working. 2 grams per 3 gallon air pot. pH started to rise and then 6 wks later started to drop keeping it within range. The other plant is a bit stunted because of the cold start so not using much nitrate so it's having the opposite problem of low pH.

I've struggled with calcium in the past but so far with lower humidity, nice vibrant green plants. Flowering is the real test but based on what I'm observing and the fact I've tried everything else, I'm pretty confident that they will finish well.

The extremes that I'm pushing (light & temp) are the reason I was having problems and could have just turned the light down. But when it goes right, the buds just sparkle and the effects are much stronger. Look up Mitch Westmoreland environment study. It's preliminary work but my tests indicate it's rock-solid. Both Mitch and his mentor, Bruce Bugbee are currently saying that temperature is the best method to crop steer cannabis. I just bought a much bigger AC unit than you'd think I'd need so I can maintain the low temps for a longer grow season.

I attached a photo but the camera makes the plants look a paler green. The are a little greener than they look but not dark green.

As Bruce Bugbee likes to say, not everyone can drive a car at 300 mph but it sure is fun when you can. (paraphrased slightly)

Here are some other things I've tried to correct calcium deficiency:
Solutions

• Twice a week foliar spray calcium chloride @ 400 to 800 ppm & pH 5.8
• Reduce N in solution
• Reduce ammonium N
• Reduce EC of solution
• Turn down light
• Reduce humidity to increase transpiration
• Reduce the K:Ca ratio if it's high. (e.g. 3:1 to 2.5:1) to reduce competition for Ca
• Defoliate - don't remove many, only want to remove microclimates to promote transpiration in centre
• Add fans - this is important!
• Blow air up directly into center of canopy from bottom of plant

OgTigerKing said:

View attachment 5446142

Click to expand...

Maybe not "verry" happy but happy enough. These plants are working HARD, there will be stress. There were some issues early on because they had a tough beginning until my tent was empty. The have only been in a good environment 2 weeks. And I'm still fighting a bit of stress but compared to previous grows this is happy. If I can get to the end without major deficiencies the end product is worth the stress to both the plant and me.

egregory6 said:

Here's a little more detail on my HLG 650R in a 3x3 tent:

For veg until 2 wks before 12/12, I run at 28-29° C and 60% humidity. Humidity goes to about 55% prior to 12/12 but is measured with the probe slightly within the top leaves. You want to monitor what the plant is feeling. Probes not in the canopy register much lower levels. 2 wks before 12/12 the temp steadily drops to 20 22° C at 2° per wk.

I'm in week 7 now at 30" above plant and at 535 watts and the plants are very happy. I usually grow 1 or 2 plants and veg 8 wks but these plants were in the cold & under a small light for the first 5 wks and are much smaller than usual. They are growing quickly now. I have back problems so fewer plants is easier for me.View attachment 5446139

For flower I try to get to full power at about 22 inches but it depends on the strain and how healthy they are. I get a little bleaching but I'm more concerned with getting max photons deeper into canopy and am willing to sacrifice a 1/4 inch of the center flowers to achieve that. I smoke the white tips and they seem fine to me. Sometimes I have to turn down the light but can usually keep it at full or close to full power.

I don't supplement CO2 but ambient in my basement in winter is over 800 ppm most of the time so I have a little bump there. I have five 6" non-oscillating fans in my tent to ensure that no leaf is robbed of air exchange. 4 on top and 1 on bottom. I will add a sixth one on the bottom soon. Just strong enough to not have wind-burn. This helps with nutrient (calcium) uptake. I also foliar spray calcium chloride twice a week or so. I avoid calcium nitrate foliar because the N can promote growth increasing the demand for calcium.

Current fertilizer is Jack's 5-12-26 with calcium nitrate. I often mix my own using Hydrobuddy. At week 7 of veg I'm at an EC of 1.8 fed 5 times per day. I try to run with only nitrate nitrogen but if runoff pH goes high, I'll use a little ammoniacal nitrogen. This run I mixed a little Sulphur into my 70/30 coco/perlite mix to keep ph low and it seems to be working. 2 grams per 3 gallon air pot. pH started to rise and then 6 wks later started to drop keeping it within range. The other plant is a bit stunted because of the cold start so not using much nitrate so it's having the opposite problem of low pH.

I've struggled with calcium in the past but so far with lower humidity, nice vibrant green plants. Flowering is the real test but based on what I'm observing and the fact I've tried everything else, I'm pretty confident that they will finish well.

The extremes that I'm pushing (light & temp) are the reason I was having problems and could have just turned the light down. But when it goes right, the buds just sparkle and the effects are much stronger. Look up Mitch Westmoreland environment study. It's preliminary work but my tests indicate it's rock-solid. Both Mitch and his mentor, Bruce Bugbee are currently saying that temperature is the best method to crop steer cannabis. I just bought a much bigger AC unit than you'd think I'd need so I can maintain the low temps for a longer grow season.

I attached a photo but the camera makes the plants look a paler green. The are a little greener than they look but not dark green.

As Bruce Bugbee likes to say, not everyone can drive a car at 300 mph but it sure is fun when you can. (paraphrased slightly)

Here are some other things I've tried to correct calcium deficiency:
Solutions

• Twice a week foliar spray calcium chloride @ 400 to 800 ppm & pH 5.8
• Reduce N in solution
• Reduce ammonium N
• Reduce EC of solution
• Turn down light
• Reduce humidity to increase transpiration
• Reduce the K:Ca ratio if it's high. (e.g. 3:1 to 2.5:1) to reduce competition for Ca
• Defoliate - don't remove many, only want to remove microclimates to promote transpiration in centre
• Add fans - this is important!
• Blow air up directly into center of canopy from bottom of plant

Click to expand...

Just keep the law of diminishing returns in mind.

Hollatchaboy said:

Just keep the law of diminishing returns in mind.

Click to expand...

Point taken and considered. But I didn't put a 650w light in a 3x3 to save money. The growth graphs level out but not flat without extra CO2. For me, it's worth the approx. $12/month in flower for the extra 300w. It only runs at full power for 2 months a grow, twice a year, three at most. I couldn't fit the 4x4 tent I wanted so I decided to get the max from a smaller space. I always ran mid to high humidity and battled calcium issues when I turned up the light. I didn't realize the huge effect lowering humidity has on moving nutrients through the plant. So much to learn, that's what makes it fun.

yeah the option to dim things down because you have excess power is better than not having enough light power

amneziaHaze said:

no i meant i leave the lolypop because when using masterblend the original recept doesnt have enough and older leafs start dying off then i bump the dose.you have a few tries to get the perfect formula until the leafs of the usefull stuff starts dying

Click to expand...

The original recipe doesn't have enough of what? Masterblend is a traditional blend with plenty of Ca and Mg in the mix? Deficiencies are solely down to grower error.

egregory6 said:

Here's a little more detail on my HLG 650R in a 3x3 tent:

For veg until 2 wks before 12/12, I run at 28-29° C and 60% humidity. Humidity goes to about 55% prior to 12/12 but is measured with the probe slightly within the top leaves. You want to monitor what the plant is feeling. Probes not in the canopy register much lower levels. 2 wks before 12/12 the temp steadily drops to 20 22° C at 2° per wk.

I'm in week 7 now at 30" above plant and at 535 watts and the plants are very happy. I usually grow 1 or 2 plants and veg 8 wks but these plants were in the cold & under a small light for the first 5 wks and are much smaller than usual. They are growing quickly now. I have back problems so fewer plants is easier for me.View attachment 5446139

For flower I try to get to full power at about 22 inches but it depends on the strain and how healthy they are. I get a little bleaching but I'm more concerned with getting max photons deeper into canopy and am willing to sacrifice a 1/4 inch of the center flowers to achieve that. I smoke the white tips and they seem fine to me. Sometimes I have to turn down the light but can usually keep it at full or close to full power.

I don't supplement CO2 but ambient in my basement in winter is over 800 ppm most of the time so I have a little bump there. I have five 6" non-oscillating fans in my tent to ensure that no leaf is robbed of air exchange. 4 on top and 1 on bottom. I will add a sixth one on the bottom soon. Just strong enough to not have wind-burn. This helps with nutrient (calcium) uptake. I also foliar spray calcium chloride twice a week or so. I avoid calcium nitrate foliar because the N can promote growth increasing the demand for calcium.

Current fertilizer is Jack's 5-12-26 with calcium nitrate. I often mix my own using Hydrobuddy. At week 7 of veg I'm at an EC of 1.8 fed 5 times per day. I try to run with only nitrate nitrogen but if runoff pH goes high, I'll use a little ammoniacal nitrogen. This run I mixed a little Sulphur into my 70/30 coco/perlite mix to keep ph low and it seems to be working. 2 grams per 3 gallon air pot. pH started to rise and then 6 wks later started to drop keeping it within range. The other plant is a bit stunted because of the cold start so not using much nitrate so it's having the opposite problem of low pH.

I've struggled with calcium in the past but so far with lower humidity, nice vibrant green plants. Flowering is the real test but based on what I'm observing and the fact I've tried everything else, I'm pretty confident that they will finish well.

The extremes that I'm pushing (light & temp) are the reason I was having problems and could have just turned the light down. But when it goes right, the buds just sparkle and the effects are much stronger. Look up Mitch Westmoreland environment study. It's preliminary work but my tests indicate it's rock-solid. Both Mitch and his mentor, Bruce Bugbee are currently saying that temperature is the best method to crop steer cannabis. I just bought a much bigger AC unit than you'd think I'd need so I can maintain the low temps for a longer grow season.

I attached a photo but the camera makes the plants look a paler green. The are a little greener than they look but not dark green.

As Bruce Bugbee likes to say, not everyone can drive a car at 300 mph but it sure is fun when you can. (paraphrased slightly)

Here are some other things I've tried to correct calcium deficiency:
Solutions

• Twice a week foliar spray calcium chloride @ 400 to 800 ppm & pH 5.8
• Reduce N in solution
• Reduce ammonium N
• Reduce EC of solution
• Turn down light
• Reduce humidity to increase transpiration
• Reduce the K:Ca ratio if it's high. (e.g. 3:1 to 2.5:1) to reduce competition for Ca
• Defoliate - don't remove many, only want to remove microclimates to promote transpiration in centre
• Add fans - this is important!
• Blow air up directly into center of canopy from bottom of plant

Click to expand...

1.8 EC 5 times a day in veg and plants still look deficient tells me something is really off. You shouldn't even have to feed half that to encourage vigorous healthy growth in veg.

Its often better to first be the observer and after gaining some real experiencing after growing for 5-10 years you may give instructions and pointers. You don't understand plant nutrition by copying someone else nutrient regime while ignoring all other measures.

egregory6 said:

Point taken and considered. But I didn't put a 650w light in a 3x3 to save money. The growth graphs level out but not flat without extra CO2. For me, it's worth the approx. $12/month in flower for the extra 300w. It only runs at full power for 2 months a grow, twice a year, three at most. I couldn't fit the 4x4 tent I wanted so I decided to get the max from a smaller space. I always ran mid to high humidity and battled calcium issues when I turned up the light. I didn't realize the huge effect lowering humidity has on moving nutrients through the plant. So much to learn, that's what makes it fun.

Click to expand...

"The growth graphs level out but not flat without extra CO2"
Which "growth graph"?

The chart below is from the Chandra paper which investigated changes in photosynthesis rates vs temperature and CO2. My hunch is that this is "the science" that the cannabis world glommed on to that leads to concerns about "the law of diminishing returns". Accepting that everything is liable to that law but it also appears that there's little point in growing cannabis much above about 600µmol.

I have no doubt that the chart is accurate but, as I said when I first read the paper, I'm not growing "net photosynthesis".

Net photosynthesis is not a valid proxy for yield.

The data re. net P in this paper was derived from taking measurements about photosynthesis from a small number of leaves in a chamber about the size of a shoe box. My grow tent is small (2' x 4') but it's larger than a shoebox and, once again, I'm not harvesting "net photosynthesis".



A team of pointy headed guys apparently felt the same way and decided to do research that looked into plant yield and it's a whole different story.

Westmoreland's videos are an excellent, succinct source, I agree completely and have changed my growing processes to support Westmoreland's advice*.

The attached paper provides details of how cannabis reacted to increased light levels. The table below is based on the data in the Frontiers document.



I've highlighted various sections of the text in the document. The text containing the word "plasticity" is key.

Delps8 said:

"The growth graphs level out but not flat without extra CO2"
Which "growth graph"?

The chart below is from the Chandra paper which investigated changes in photosynthesis rates vs temperature and CO2. My hunch is that this is "the science" that the cannabis world glommed on to that leads to concerns about "the law of diminishing returns". Accepting that everything is liable to that law but it also appears that there's little point in growing cannabis much above about 600µmol.

I have no doubt that the chart is accurate but, as I said when I first read the paper, I'm not growing "net photosynthesis".

Net photosynthesis is not a valid proxy for yield.

The data re. net P in this paper was derived from taking measurements about photosynthesis from a small number of leaves in a chamber about the size of a shoe box. My grow tent is small (2' x 4') but it's larger than a shoebox and, once again, I'm not harvesting "net photosynthesis".

View attachment 5446377

A team of pointy headed guys apparently felt the same way and decided to do research that looked into plant yield and it's a whole different story.

Westmoreland's videos are an excellent, succinct source, I agree completely and have changed my growing processes to support Westmoreland's advice*.

The attached paper provides details of how cannabis reacted to increased light levels. The table below is based on the data in the Frontiers document.

View attachment 5446382

I've highlighted various sections of the text in the document. The text containing the word "plasticity" is key.

Click to expand...

Increasing light intensity doesn't equate to higher potency, yield yes depending on situation but not in any way potency. That's down to the quality and range of the light and overall plant health.

Some of the most potent flowers I ever smoked was grow under fluorescent bulbs with comparably very low light intensity.

The work that I've found most interesting recently is Mitch Westmorland's where he identifies temperature as the best thing to focus on for higher THC concentration. I have experimented once with his methods and the results were outstanding. I'm on my second attempt now with about 2-3 weeks before I start turning the temps down. This point really got my attention:
Rate of cannabinoid accumulation increased from 50% at 10 C to a maximum at 20-22 C and rapidly declined to 20% of the maximum at 28 C.

His actual study is behind a pay-wall but the abstract is here: Optimizing Temperature for Yield and Quality of Medical Cannabis Search YouTube for Mitch Westmoreland to get details. Two good ones are the Migro & The Future Cannabis Project sessions with him. Highly recommended. Bruce Bugbee has done at least one with Migro on the same subject. He talks about multiple subjects but touches on this study.

While it's true light intensity doesn't generally improve cannabinoid concentration, it will increase the quantity of THC harvested per area by driving biomass expansion. Important for people who like to further process the product, like me. You will also harvest potent THC from lower in the plant and from the extra biomass. High intensity also helps ensure a quality product. More research is needed on the dilution effect to discuss causation.

Here is a different study that looked at going to 1400 umols/m2/sec without CO2 supplementation: Cannabis yield increased proportionally with light intensity, but additional ultraviolet radiation did not affect yield or cannabinoid content

The current thinking on the Chandra studies setting 600 and 1000 umol veg and flower targets is that they studied photosynthesis of individual leaves while current research measures the entire canopy photosynthesis. It turns out that when you do that, photosynthesis increases past 60 mols/day and the curve doesn't flatten at 60.



This is the growth graph I was referring to. It's from a 2024 Westmoreland study without supplemental CO2. That's 1380 umols/m2/sec. The curve is still steep enough to indicate it can go higher. Each grower needs to determine their own economic threshold but new research is blowing up old maximums all the time now.

Some may be content to do it the same way every time and have perfect plants to show everyone while others like to experiment and push limits. I do have a lot to learn but I have an open mind and a passion for learning. I will get there. I have 4 years experience now and wanted to start giving back...

I delayed posting on Rollitup because I've observed that it's a slightly toxic place. This is supposed to be a community forum of like-minded people trying to accomplish the same goals in different ways. That is not what it is so this will be my last post. Too often an interesting post devolves into insulting or disrespecting other users. You really should be courteous to new people. And you should be more open to ideas that may not conform to your own. And you should be current with new ideas before you jump on others Oh wait, you should never jump on others. This describes most users here but some few are ruining it. You shouldn't tolerate this and demand that all users treat all other users with respect. There's also too many people posting without contributing anything. Is bumping up your profile that important? It's like the Twitter (formerly) of cannabis forums.

I'm not invested enough to care, but some of you long-term people should get a new sheriff. Individual users can also actively discourage bad behavior and report it when someone doesn't respond appropriately. You're missing out on a lot of valuable input. I don't imagine I'm the only person who stays away because of the tone here. You can't read more than a few posts before you encounter one of these toxic messages.

Sorry to see you get discouraged egregory. This forum can certainly get off track and can also be a mean place sometimes. That said, some of the most insightful envelope-pushing threads I’ve seen here were riddled with trolls, name calling, and bullying.

Those were the good ol’ days.

Unfortunately, anywhere in society where there is public dialogue, you will get into the mud a bit because people have different knowledge, experiences, opinions, etc… and everybody wants to be right/grow the best bud/have the best light and so on. This, in my opinion, is what keeps progress moving forward. It’s not all hugs and snuggles but it’s real, raw and unfiltered discourse. When somebody says something off or incorrect, they get corrected pretty quick or at least it opens up a conversation where many people can chime in and everyone has the opportunity to learn. When the mods shut down these dialogues, delete comments or close a thread because somebody got their feelings hurt, the entire community loses out. All public places, in person or online have the potential to become toxic, because, well people are involved. That doesn’t excuse outright bullying, or comments that only serve to hurt and not contribute, but just realize that the world can be crass.

But that shouldn’t discourage you from participating

Back to the topic of lighting spectrum and intensity effects on quality…

Many people have cited Dr. Bruce Bugbee & Mitch Westmoreland talking about the effects of light spectrum on secondary metabolites, or the lack there of… I just watched the Bugbee/Migro podcast from earlier this year where Bruce said they found no cannabinoid differences between different lighting spectra, though from his own study the results show a 10% difference in CBD between HPS & LED (no difference in THC) but whatever.

I know I’ve mentioned it before and I’m likely going to ruffle some feathers, but theses dudes are NOT the ultimate authority on cannabis science. Some of what they say just isn’t representative of drug type cannabis (they both grow non-THC hemp), and their methods serve to show the shortcomings of not only their experiments, but the conclusions one can draw from them regarding drug type cannabis.

There have been multiple studies (some I will link below) that show distinct differences in cannabinoid/terpene types and concentrations resulting from different light spectra and intensities.