Diary PCBuds mini-grow

[SuperBadGrower]

I think they'll both be fine.
They are probably both going to take forever to finish but I'm used to that. I'm in no rush.

Hey Super, ... What current do you have your strips set at and will I be able to turn mine up as she gets used to the lights?

Hmm, I'm using them in various setups, some are around 625 mA and others around 900. That's kind of the range where I use them personally. I have to maintain a healthy distance from the plants, but all my strips are very close together unlike yours. As Greengenes has said, 'density is intensity'.
edit: (I only use 2ft stips)


I think it really depends on the plant! In flowering mode it's a totally different story compared to veg, they can handle a much higher intensity. Some plants love light more than others.
I'll say this: using them as a "normal" light from the top, I have had plants grow up to and in between the strips (650 mA and close together) and they didn't really care at all. My experience however is that there can be heavy foxtailing or "eternal growth" at such intensities. The plants don't suffer like they do in veg but they can have trouble finishing.

Since your strips are spaced out much more than mine, or most people's, I think you can be pretty lenient with it in flower, especially week 2 onwards. if they start to look stressed it will show itself. =)

 

[SuperBadGrower]

Yeah, in veg I have to dim really quite low compared to flower, lower than I ever thought before using/making LEDs. With a fixture designed for flowering, dimming it to 50% is sometimes not even enough depending on vertical space. I have to hang the light significantly higher for them to veg healthy. Just my experience in my situation of course, none of that is gospel

(All depends on the temps too, you basically should be able to go naked or shirtless in the room and still feel warm, ideally)

 

[PCBuds]

When you say 50%, do you mean 50% of the test current or the max current?

I'm kinda just guessing by looking at the brightness right now.
Measuring the current is a pain but I have some little inline current/voltmeters coming.

Edit: oops I missed your first post.

 

[PCBuds]

My plant went from the window with three ten Watt 800-lumen SILs to the closet where I flipped her to 12/12 right away.

So she is in flower now but dealing with the new lights, being really wet, being transplanted and too much light all at once.
I'm pretty hard on my plants. Lol

I think I just got lucky with the White Widow in that it has always put up with my BS and I've never hermed one.
It was listed as "easy to grow" and it's the only thing I've ever really grown.

 

[PCBuds]

Ohh...
Are you using heat sinks?

What kind of temperatures do your strips get up to?

 

[SuperBadGrower]

Yeah, I use aluminium channel for the 900mA strips. The strips are cheap enough that running 2 at 700 is better than 1 at 1400. Never saw a need to go over 1000 mA.
I like to put them on aluminium for construction purposes, but it costs a bit more. When I touch the aluminium, it's comfortably warm, but never hot. On diodes I've measured anything from 40 to 70 C, but it's impossible to measure accurately for me without good equipment.

I have used them bare at 900 mA and the back side gets too hot to touch after 5-10 sec, so that's not good. They will work fine, but even if you don't care about the efficacy loss "right now", you would be wise to remember that you are also accelerating their degradation.

I don't measure the current actually, it's just based on dividing the amperage of the driver. 10 things in parallel on a 3A supply will get 0.3A each. Any system losses are negligible. I use a watt meter to check if the wall draw is as it should be.

edit: Many HLG drivers dim to 50% only. A flower light is generally 30-40w/sqft - so what I meant is, if I"m vegging in a place that is designed for flowering, I'll need to dim those strips to 50% and raise them.

 

[PCBuds]

The total output of my drivers right now is ~51 Watts but the draw from the wall is 105 Watts.
(that included the draw from timer and contactor as well but they should just be a few Watts)

So it looks like my power supplies are about 50% efficient at the new setting with them turned down.
(They were about 83% efficient when they were turned up higher.)

It's a bit difficult to know how to calculate the Watts/square foot because I don't know if I should include the power draw of the driver and I have no idea how to judge the lighting on the walls, so I'm just going to keep an eye on the temperature and not overheat them.

It's good to know that they did need to be turned down from the point I had them at where they wouldn't get too hot.
That means I should be able to safely turn them up when my plant gets a bit bigger.


My closet measures 21" X 21" with 5-foot walls.

I use an IR thermometer to take the temperature readings. I think it's pretty accurate but it's hard to aim it at the little temperature test point while the light is beaming me in the face.

 

[SuperBadGrower]

The total output of my drivers right now is ~51 Watts but the draw from the wall is 105 Watts.
(that included the draw from timer and contactor as well but they should just be a few Watts)

So it looks like my power supplies are about 50% efficient at the new setting with them turned down.
(They were about 83% efficient when they were turned up higher.)

Sounds about right (drivers perform better at max), a little low on the dimmed setting. depending where you measure you may have losses due to length of wire etc.

It's a bit difficult to know how to calculate the Watts/square foot because I don't know if I should include the power draw of the driver and I have no idea how to judge the lighting on the walls, so I'm just going to keep an eye on the temperature and not overheat them.

Lets say that the 30w/sqft thing is based on ~95% efficiency from the driver. (tpical Meanwell rating)
However it's also based on getting the light in there from the top. WIth such a lighting set up, I honestly have no idea. I think you can use less light than top lighting.

I learned that it's not worth it to mull over the details. As a hobbyist you will never have the right equipment to do proper testing.

For measuring light accurately you need a PAR meter which is $500. That's a waste of money unless your canopy space exceeds like 50 sqft

It is possible to use a Lux meter and use conversion rates to go from lux to ppfd. Migro did a video about this recently: https://www.youtube.com/watch?v=YiVVAePNtXo

Different meters give different results. They can't be trusted without comparison to a proper quantum meter. E.g. my own lux meter under-reports by about 30%. That is a lot

Thankfully, as you could see, it is easy to diagnose light stress, especially once you are familiar with it.

I use an IR thermometer to take the temperature readings. I think it's pretty accurate but it's hard to aim it at the little temperature test point while the light is beaming me in the face.

I use that too, not sure how accurate they are. Usually they seem fine. I have in the past pointed it at something that was scorching hot, yet it would fail to register anything higher than 40 C. That might have been a liquid though.

https://www.ncbi.nlm.nih.gov/pubmed/15877017

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2600390/

I guess, like all the cheap chinese measuring equipment, "it gets you in the ballpark". They have absolute disregard for accuracy and precision over there. That's one reason why their buildings and roads collapse, killing unimaginable number of humans each year.

 

[PCBuds]

Thanks, SuperBadGrower for taking the time to respond.
I realize you are responding based on your own experience but I have no other input from any other LED strip growers.

Sounds about right (drivers perform better at max), a little low on the dimmed setting. depending where you measure you may have losses due to length of wire etc.

Yeah, I do.
The total current is always the same in a circuit but I have a voltage drop across the wires of about 0.3 Volts which is significant with my voltage regulated power supply.

The current too isn't shared equally between the top and bottom strips because the upper strips are warmer and draw more current.

I just use the current reading out of my driver and assume equal sharing of current.
I will keep a closer eye on the upper strips.
I took my recent voltage reading at the power supply too because it's pain to get the reading off the installed strip.

Lets say that the 30w/sqft thing is based on ~95% efficiency from the driver. (tpical Meanwell rating)
However it's also based on getting the light in there from the top. WIth such a lighting set up, I honestly have no idea. I think you can use less light than top lighting.

I learned that it's not worth it to mull over the details. As a hobbyist you will never have the right equipment to do proper testing.

For measuring light accurately you need a PAR meter which is $500. That's a waste of money unless your canopy space exceeds like 50 sqft

It is possible to use a Lux meter and use conversion rates to go from lux to ppfd. Migro did a video about this recently: https://www.youtube.com/watch?v=YiVVAePNtXo


Different meters give different results. They can't be trusted without comparison to a proper quantum meter. E.g. my own lux meter under-reports by about 30%. That is a lot

I used my phone with a LUX meter app to take some readings.


https://www.icmag.com/ic/showpost.php?p=8799568&postcount=692


https://www.icmag.com/ic/showpost.php?p=8799612&postcount=693


I didn't care too much about the actual numbers, just the ratio between different measurement distances comparing my new strips to my old SILs to get an idea of how they compare.

To try to get a total lumens output, I use the total current draw X the voltage at the strip X the lumens per Watt rating.
(I wonder if my lm/W rating is higher at less than test current?)

Either way, that number is kind of erroneous to me because I'm using strips now and using them in an unusual way.

I didn't keep very good track of anything with my SILs either except to count the bulbs, and I had a 4' fluorescent fixture as well.

Thankfully, as you could see, it is easy to diagnose light stress, especially once you are familiar with it.

I've really got to pay more attention to my plant and learn to read it better.

It is nice to know that I can stress my plant with light even though my strips are turned down below 50%.
(the 2' strips were at 586 mA before I turned them down even further).

I wanted to set my strips at a low enough power where if my fan failed they wouldn't overheat.

I use that too, not sure how accurate they are. Usually they seem fine. I have in the past pointed it at something that was scorching hot, yet it would fail to register anything higher than 40 C. That might have been a liquid though.

https://www.ncbi.nlm.nih.gov/pubmed/15877017

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2600390/

I guess, like all the cheap chinese measuring equipment, "it gets you in the ballpark".

A ballpark reading is good enough for me but it would be nice to get a more accurate reading of the temperature though.

I checked out the links you posted and it sounds to me like the inaccuracies of checking a person's forehead for fever has more to do with the actual temperature of the forehead compared to a person's core temperature, especially if you're old.

The IR thermometer may have been quite accurate. (although my $10 might not be. Lol)

From all the comments I read before purchasing mine, it seemed like they either worked or they didn't. They either completely died or gave a ridiculous reading that you knew was wrong.

I'm going to try to "calibrate" mine a bit using a regular thermometer but I'm not going to try to touch a regular liquid-filled thermometer to my test point. I don't think that would be very accurate at all.

I know that the IR thermometers don't work on shiny surfaces and my instructions say to put masking tape or magic marker on a shiny test point.


My 2' strips have solder on the temperature test points but my 1' strips are copper which is kinda shiny.
I should put something on the test points.


I'd like to get to a point where I can simply touch the strips to do a temperature check and just look at my plant to see if it's too much or too little light.

Nice and simple no instruments at all.

 

[SuperBadGrower]

Hehe no problem. If you can put your hand on the back of a strip or the aluminium it is attached to indefinitely, it's running cool enough. Yes lm/w or µmol/j (luminous efficacy) increases at lower current, although not by huge amounts. EB gen 2 is about 2.55 µmol/j according to some test. You can use the following formula to conjure up a ballpark ppfd:

(w * 2.55) / a

w=watt, a = area in m².

(the D in PPFD is density, expressed in m². For flowering without CO2 you would like to have 650-850 ppfd)

 

[PCBuds]

So, ... Right now I have a total of 51 Watts going to all my strips.

My area is 21"X21" = 3.06 square feet for the ceiling and 21"X60" X4 =35 square feet for the walls so, .. 38 square feet is just about 3.5 square meters.

So, 51X2.55÷3.5= about 37 ppfd which sounds quite wrong, but if I took all my strips and put them on the ceiling I would get.

51 X 2.55 ÷ 0.284= 458 which sounds more reasonable especially since my strips are turned down well below 50% right now.


But I'm sure I'm comparing an apple to an orange and I think a better way to look at it is total lumens going into the grow cab.


So 51 Watts X 175 lumens per Watt (perhaps a bit more with the current below half) equals 8,900 lumens.

The three 10 Watt SILs were 2,400 lumens plus say 35% more with the globes removed, so 3,240 lumens.

So about 2.75 times more light now in the closet than it had on the window sill.


Does all that sound right?
I'm not sure about the math.

 

[PCBuds]

Another way I'm thinking of it is if you have say, 750 ppfd on the ceiling with normal downward facing lighting in a grow cab measuring 1 cubic meter.

Then instead of 750 on the ceiling, you divide it up evenly with all the four walls too and get 250 ppfd per surface.

I'm guessing that the plant would make better use of the same total amount of light and grow better with a higher yield.

 

[PCBuds]

My plant just woke up.

She's looking pretty darn good now!!

That didn't take long at all.

Some of the upper leaves ended up kinda twisted but I can ignore that.









The temperature is a little low so I was considering putting a heater in the closet but then realized that I don't really have an easy place to run a power cord into the closet so I'm going to ignore that too!! Lol





The temperature higher up in the closet was about 70° F and the humidity was reading 50%.
The lights had been on for about 10 minutes.

 

[PCBuds]

Oh, ...

My cat doesn't easily fit in the closet right now so this is for scale...





The purpling appears to have stopped but I don't know if the leaves/stems are too young to show.







The new growth is OK.

 

[SuperBadGrower]

divide it up evenly with all the four walls too and get 250 ppfd per surface.

I'm guessing that the plant would make better use of the same total amount of light and grow better with a higher yield.

Yep, that's what I think.

Putting the air exhaust at the bottom (if you have one at the top) can draw some rising warm air to the canopy and substrate. that might increase the temperature by a degree or more.

 

[PCBuds]

Then instead of 750 on the ceiling, you divide it up evenly with all the four walls too and get 250 ppfd per surface.

I'm guessing that the plant would make better use of the same total amount of light and grow better with a higher yield.

But, ... Perhaps another way to look at it is that as a plant grows it gets closer and closer to the lights with their heat and intensity and starts producing more resin as a stress response.

So maybe half of the light from the top and the rest on the walls so the lower leaves get more of what they need to help feed the buds what they need??
I dunno?

I really like how you said that your plants could grow right past the strips with no problems. (except the fox tailing and new growth)
My buds would burn if they got that close to my SILs.

Putting the air exhaust at the bottom (if you have one at the top) can draw some rising warm air to the canopy and substrate. that might increase the temperature by a degree or more.

That would be a bit of a chore right now and I have a bigger issue with too much heat in there during the summer months when it goes over 90°F.

I am intending to put the fan at the bottom though after this plant so I can blow air through the furnace filter (that' supposed to catch pollen) into the closet to pressurize the closet so no dust or pollen gets in.

Then I want to cut a 21" strip opening across the top of the closet about 1"-2" wide to vent freely, then I can lower my 2' strips about 3"-4", with the fan out of the way so they have some headroom and aren't in the hottest part of the closet.

 

[PCBuds]

This is a good video explaining what PAR, PPF, PPFD, and the new PFD mean...

(it's not a personal floatation device. Lol)

https://youtu.be/UZO8Fb0ryW8


This looks like a good one too...

Cannabis grow lighting myths and FAQ's.
(I haven't watched it yet because I have to pay attention for 45 minutes. Lol)

Dr. Bugbee really knows his stuff!!


https://youtu.be/ID9rE5JewVg

 

[q3corn]

My cat doesn't easily fit in the closet right now so this is for scale...

Can't all be winners

 

[PCBuds]

I was staring at these leaves and got to thinking... (yeah, I was stoned too. Lol)








Maybe the plant has curled its leaves to make "vortex generators" to draw air past its surface turbulently and pull off evaporation more effectively to pull water out of and away from its flooded root system?

A bit like this...





... But in a more 3-dimensional way.
(unlike the way us 2-dimensional humans think.)



I think I have a momentum deficit.

I'm stoned and don't want to get off my ass. Lol

 

[PCBuds]

Can't all be winners

I've got a lot of space above the plant so maybe I could put in a shelf above it and install my cat there?? Lol