LED and BUD QUALITY

[greyfader]

so, the first pic shows crooked8's light fixtures. we can clearly see two types of "white" light diodes, warm white 3000k and cool white 5000k plus the the 660nm dark red. i'm not sure what the blue diodes are, but possibly UV. maybe crooked8 can tell us.

and the ratio of warm white to cool white is 2/1 which also seems to be the recipe most led manufacturers are using.

the second one shows what the 3000k and 5000k spectral distribution looks like. the third one shows 3000k warm white plus 660nm diodes.

all approximate but looking at these i don't see that he has enough blue light to cause the leaf taco that he shows in some pics because his blue/red ratio is what we should be looking at overall. his lights are typical for the industry. most led manufacturers use this light recipe.

also, some of crooked8's plants show the taco and some don't which has me wondering whether they are in the same room or, if they are not, do they have the same temperature and rh%.

because if they are in the same room or an identical one with the same parameters of temperature and rh% it would tend to make me believe that some strains are more prone to display the taco than others.

my pics got reversed some on this post but you know what i mean.

 

[CannaT]

i immediately went to my little 2-plant experimental grow which is in late veg. i had a room temperature of 84f and top leaf temperature of 82f.

The corresponding chart for a minus-two F condition shows that my ideal vpd is .91 to 1.14 which is 70%-65% RH respectively.

my room is 56% so i'm off some but there's not a fucking thing i can do about it in this old, leaky house.

i want a sealed room again so i can play god to my plants. i will be there soon. can't wait

Its such a high humidity I will use this for Veg plants never in late flower.

 

[greyfader]

Its such a high humidity I will use this for Veg plants never in late flower.

yes, if you look at the -2F chart for late flower with a room temperature of 84F and a leaf temperature of 82F the ideal vpd is 1.34-1.54 kpa which is 60%-55% RH. This supports the general recommendation of using 55% plus or minus 5% in late flower. towards 60% lights on and 50% lights off.

i generally use the ac and a dehumidifier, if necessary, to control lights on RH and put a timer on a second dehumidifier to start drying down the room about an hour before lights off.

 

[Ca++]

I don't know his RH/VPD but it could also be related to the burnt edges. We know K was low anyway, but I myself have no gauge of how low should cause problems of a particular intensity.
Water loss, while related to the edges, and the taco, doesn't meet my expectation regarding the colours. I have seen leaves taco and thicken, while taking on a darker colour under LED. Even though the RH was reasonable (60% late bloom) but the colour reminds me of HPS. Which as bloody great heaters, certainly would effect the VPD directly around them.

It's in the balance there somewhere. It could even come back to K that forcing water loss protection, and the colour could just be from stress, if it's only on plants known to be colourful.

All we can really do is present options. VPD is a good one.

 

[WingzHauser]

my pics got reversed some on this post but you know what i mean.

That's royal blue (460).

Leaf taco is a nutritional deficiency. B Mg Zn K. I'll let you take you pick as I'm sick of the favoritism given to single nutes. You have a 25% chance of learning something if you foliar spray your next tacked plant.

 

[Crooked8]

Looking again (before getting stoned) I see the curled edges are all coloured from carotinoids. This is light avoidance, seen more often outdoors, than in. Suggesting it's the blue light interfering with leaf function.

It does seem that all the upward curl is only on the tops closest to the lights and only on strains with more anthocyanin production. I have tops showing none at all on og strains.

 

[Crooked8]

so, the first pic shows crooked8's light fixtures. we can clearly see two types of "white" light diodes, warm white 3000k and cool white 5000k plus the the 660nm dark red. i'm not sure what the blue diodes are, but possibly UV. maybe crooked8 can tell us.

and the ratio of warm white to cool white is 2/1 which also seems to be the recipe most led manufacturers are using.

the second one shows what the 3000k and 5000k spectral distribution looks like. the third one shows 3000k warm white plus 660nm diodes.

all approximate but looking at these i don't see that he has enough blue light to cause the leaf taco that he shows in some pics because his blue/red ratio is what we should be looking at overall. his lights are typical for the industry. most led manufacturers use this light recipe.

also, some of crooked8's plants show the taco and some don't which has me wondering whether they are in the same room or, if they are not, do they have the same temperature and rh%.

because if they are in the same room or an identical one with the same parameters of temperature and rh% it would tend to make me believe that some strains are more prone to display the taco than others.

I cant find as much info as id hoped but im going to contact agro and see if they can tell me their specific diode use. For now, here are the fixtures spec sheets….

https://grow.agrolighting.com/hubfs/ABU%20720%20Specification%202023.pdf?hsLang=en

As for temp and rh, its nearly identical throughout the room. Towards the center there is a slight dip in leaf temperature because all the air conditioning and fans converge there. I try to reduce this by using floor fans to keep everything moving above and below the canopy. Nothing is extreme enough of a change anywhere to cause the roll, i do think its strain dependent and for whatever reason, strains that turn purple hues have it and anything green does not.

 

[Crooked8]

next, i went to the dimlux site to study how their lights are made and while there i found interactive vpd charts. they allow the grower to compare the differences in vpd based on room temperature and rh% but also leaf temperature. it is the first vpd chart i've seen that takes into account leaf temperature as well.

i could not get the interactive chart to download so i copied them all to make the comparison easier.

the charts show the differences in vpd between room temperature and leaf temperature plus rh%.

they are labeled but i put them in order as well. they are for 0%, -!%, -2%, -3%, -4%, and -5%.

i think crooked8's taco leaves are vpd related and strain specific.

I do think it is strain specific in that maybe each one has its own general ideal VPD at certain stages. This is monitored constantly and we are pretty predictable with what we follow. This is our VPD schedule.

Veg
Early veg we stay between .8-.9kPa
Late veg(like right before the flip) .9-1.0

Flower
Weeks 1-3 swings from .98-1.12
Weeks 4-6 swings from 1.1-1.2
Weeks 7-9 swings from 1.1-1.3(this is the time where we do stress them a bit to keep the room dry to avoid fungal issues as well as produce a deeper color and overall more terpy product, this is also notoriously when i see some roll set in)

 

[Crooked8]

i immediately went to my little 2-plant experimental grow which is in late veg. i had a room temperature of 84f and top leaf temperature of 82f.

The corresponding chart for a minus-two F condition shows that my ideal vpd is .91 to 1.14 which is 70%-65% RH respectively.

my room is 56% so i'm off some but there's not a fucking thing i can do about it in this old, leaky house.

i want a sealed room again so i can play god to my plants. i will be there soon. can't wait!

I bet one of these would get it up there pretty quick unless your veg is huge. These are so versatile and easy to move and pretty damn cheap.

Amazon.com

 

[Crooked8]

That's royal blue (460).

Leaf taco is a nutritional deficiency. B Mg Zn K. I'll let you take you pick as I'm sick of the favoritism given to single nutes. You have a 25% chance of learning something if you foliar spray your next tacked plant.

At week 3 our tissue test suggested high B, and slightly high Mg, Zn and K were both on the tad low side. At this time, none of the plants displayed any curl. I agree that its VPD and strain related. Some strains even in a harsher/dried vpd display none, when other anthocyanin producing strains seem to curl up a lot at the end of the cycle when i have it the coolest and driest environmentally.

 

[GrowdoBaggins]

At week 3 our tissue test suggested high B, and slightly high Mg, Zn and K were both on the tad low side. At this time, none of the plants displayed any curl. I agree that its VPD and strain related. Some strains even in a harsher/dried vpd display none, when other anthocyanin producing strains seem to curl up a lot at the end of the cycle when i have it the coolest and driest environmentally.

Is taco not due to heat?

 

[Crooked8]

Is taco not due to heat?

No, not just from heat, especially not in this case. Leaf surface temps are 72-75 degrees with the condenser swing.

 

[CannaT]

I think if its only on top of plants and only on purple strains.
It is very low light burn cuz purple or black leafs can acumulate more heat and light.
And its just old leaf that is losing its water procent.
Nothing to worry about.

 

[goingrey]

That's royal blue (460).

Leaf taco is a nutritional deficiency. B Mg Zn K. I'll let you take you pick as I'm sick of the favoritism given to single nutes. You have a 25% chance of learning something if you foliar spray your next tacked plant.

You are right I misread it to be 400 where it is 480 f me

 

[Crooked8]

I think if its only on top of plants and only on purple strains.
It is very low light burn cuz purple or black leafs can acumulate more heat and light.
And its just old leaf that is losing its water procent.
Nothing to worry about.

Im truly not worried about it, overall, things look real nice in there. As long as i continue to improve, im happy. Its a lot of fun figuring this stuff out!

 

[ZK7]

Since we are talking about vpd and humidifiers

Would a humidifier work in a room that isn't sealed with a intake and outake fan? I've never tried it

 

[Crooked8]

Since we are talking about vpd and humidifiers

Would a humidifier work in a room that isn't sealed with a intake and outake fan? I've never tried it

It would be less efficient, but would still bring rh up if its a decent size. Also, it totally depends how big and fast your fans are. If youre moving tons of CFM then it wouldnt work as well. People assume the same thing about co2, that the room must be sealed. This is not the case. There is an exhaust on my room dialed down to 35%. They enrich with co2 in greenhouses with intake and exhaust fans. Heres why, if you dont enrich, the plants will literally mine the air down to way below ambient levels, into the 200 range which reduces crop yields like crazy. Often times they enrich just to get to ambient or just above that 450-500ppm mark. This is why anyone and everyone should be enriching with co2 if you grow indoors. The cost/effort is always next to nothing compared to yield increase.

 

[Loriented]

Just curious. Has anyone ever watered with carbonated water. I used carbonated water once back in the 80s to spray on my plants. That was my only indoor grow ever. But I just read this...One often cited study by the University of Colorado Boulder in 2002, found that plants watered with carbonated water grew more than twice as fast and developed healthier shades of green over a 10 day period.

Does watering indoor plants with carbonated water boost growth?

Don't throw out your Soda Stream! It turns out carbonated water can actually benefit our house plants, but there are a few things to watch out for before you pick up the bubbly next time you water. How does carbonated water benefit indoor plants? Fizzy water. Sparkling water. Soda water. It's...

www.lovethatleaf.co.nz

 

[Crooked8]

Just curious. Has anyone ever watered with carbonated water. I used carbonated water once back in the 80s to spray on my plants. That was my only indoor grow ever. But I just read this...One often cited study by the University of Colorado Boulder in 2002, found that plants watered with carbonated water grew more than twice as fast and developed healthier shades of green over a 10 day period.

Does watering indoor plants with carbonated water boost growth?

Don't throw out your Soda Stream! It turns out carbonated water can actually benefit our house plants, but there are a few things to watch out for before you pick up the bubbly next time you water. How does carbonated water benefit indoor plants? Fizzy water. Sparkling water. Soda water. It's...

www.lovethatleaf.co.nz

Not sure how this would be beneficial. Roots dont breathe co2 like shoots do, they breathe oxygen, like we do.

 

[greyfader]

I do think it is strain specific in that maybe each one has its own general ideal VPD at certain stages. This is monitored constantly and we are pretty predictable with what we follow. This is our VPD schedule.

Veg
Early veg we stay between .8-.9kPa
Late veg(like right before the flip) .9-1.0

Flower
Weeks 1-3 swings from .98-1.12
Weeks 4-6 swings from 1.1-1.2
Weeks 7-9 swings from 1.1-1.3(this is the time where we do stress them a bit to keep the room dry to avoid fungal issues as well as produce a deeper color and overall more terpy product, this is also notoriously when i see some roll set in)

it can be difficult in a large room running multiple strains to find a group of strains that all have similar enough growth traits to allow you to grow them all without issues. i have had to ditch nice strains before just because they didn't fit in with the rest of them.

that may be all you are dealing with here. most of your plants look unaffected.