PAR level for seedlings? @300?

Hello all,

I have some seedlings that are starting to get their second set of leaves. They are about a week old. I just put the jiffy pellets they were germinated in into soil in 1 gallon fabric pots. I have them under a 100W LED right now. The manual with the light recommended that the light be at 60% and 20-24" above. I just bought a PAR meter and when measuring, I was getting about 200 UMOL at that height. I lowered the light a bit and now am getting around 300 right at the seedling tops. I have read a few reference sources that say anywhere from 200-400. Just wanted to get some thoughts on light levels. I want to give them as much as they need but not so much to negatively affect them/

Thanks!

Nwtexan said:

Hello all,

I have some seedlings that are starting to get their second set of leaves. They are about a week old. I just put the jiffy pellets they were germinated in into soil in 1 gallon fabric pots. I have them under a 100W LED right now. The manual with the light recommended that the light be at 60% and 20-24" above. I just bought a PAR meter and when measuring, I was getting about 200 UMOL at that height. I lowered the light a bit and now am getting around 300 right at the seedling tops. I have read a few reference sources that say anywhere from 200-400. Just wanted to get some thoughts on light levels. I want to give them as much as they need but not so much to negatively affect them/

Thanks!

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Jesus my friend you are seriously over thinking this. Worry about hitting them hard with light when you're in flower. In veg you just give them light. It doesn't need to be intense and you certainly don't need to think this hard about it. I run two 110w quantum boards in my 5x5 nursery mounted as high as I can get them. You're building flower sites and foliage in veg. Focus on intensity in flower. I have never used a PAR meter. Learn to read your plants by what's happening to the foliage.




My COB I do the same with. It's mounted as high as I can get it:


And the flowers to follow:

Oh no.


He's the one that got a PAR meter. After months of study. Trying to correlate the PAR with Umol and PPFD....


I'm out. I'm not touching this thread. I hated every second of doing LED research. Pages and pages in the journal. I've made friends with LUX. Y'all can have the Quantum meters.

Man.. No stress here.
I appreciate the replies. I'm all "journey is the destination". Getting the meter is cool, and I like to see the light levels.
Ive had successful grows in the past and just trying to learn a little as I go.
My light has a dim function, and I figure to use it as to not waste electricty.
Right now I have it at 60%. I figured it would be cool to maximize the amount of light that was good at this stage.

Nwtexan said:

Man.. No stress here.
I appreciate the replies. I'm all "journey is the destination". Getting the meter is cool, and I like to see the light levels.
Ive had successful grows in the past and just trying to learn a little as I go.
My light has a dim function, and I figure to use it as to not waste electricty.
Right now I have it at 60%. I figured it would be cool to maximize the amount of light that was good at this stage.

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Your mind is in the right place. Cool tools are fun to play with No knock on your PAR meter. It is simply unnecessary and more of a toy than a tool. Again, toys are fun. Just don't confuse them with tools If your light is 100w you turn the dimmer to full power and mount the board high. If the plants respond negatively (which at 100w they will not), dial it down the following day. However as you can see in the above photos I run two 110w boards at full power without issue from clones to full grown vegetative plants about to enter the flower room. I've never experienced any light / foliage damage.

I can't believe how overly complicated some folks make this stuff. I've never looked at nor do I care to look at a graph or stupid chart some company made up about their light. I want to know what chips are onboard, what drivers are powering those chips, and what the warranty is. How is a light chart going to help you grow your plants better? Most of the time the manufacturer's don't even know what they're talking about when it comes to growing plants. They know how to make hardware, but they generally know jack shit about growing plants. If I followed spider farmer's recommendations on light distance from the canopy my plants would be fried and never make it into the flower room. Learn to read your plants. Learn to read hardware specs. Not pretty multi colored charts with lots of numbers. And by all means play with that sweet PAR meter, but do remember it's a toy Your eyes are a much better tool. More reliable too.

jonnynobody said:

Your mind is in the right place. Cool tools are fun to play with No knock on your PAR meter. It is simply unnecessary and more of a toy than a tool. Again, toys are fun. Just don't confuse them with tools If your light is 100w you turn the dimmer to full power and mount the board high. If the plants respond negatively (which at 100w they will not), dial it down the following day. However as you can see in the above photos I run two 110w boards at full power without issue from clones to full grown vegetative plants about to enter the flower room. I've never experienced any light / foliage damage.

I can't believe how overly complicated some folks make this stuff. I've never looked at nor do I care to look at a graph or stupid chart some company made up about their light. I want to know what chips are onboard, what drivers are powering those chips, and what the warranty is. How is a light chart going to help you grow your plants better? Most of the time the manufacturer's don't even know what they're talking about when it comes to growing plants. They know how to make hardware, but they generally know jack shit about growing plants. If I followed spider farmer's recommendations on light distance from the canopy my plants would be fried and never make it into the flower room. Learn to read your plants. Learn to read hardware specs. Not pretty multi colored charts with lots of numbers. And by all means play with that sweet PAR meter, but do remember it's a toy Your eyes are a much better tool. More reliable too.

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I totally get where you are coming from, and I naturally tend to find things that work and not get into the minutia.

When I grew before I was using MH and MPS and messing around with Hydro.

This time, I am jumping into the LED world, which I think is really cool. In trying to figure out how best to cover my room and how to maximize my assets(light vs electricity) I have naturally done some reading and studying. It's hard to break through the crust of internet "knowledge" to what is really going on. There have been a few pretty extensive studies on light and yield. I'm sure they have been debated ad nauseam on the forums. They give some pretty direct correlations. I'm not basing much on any manufacturers data, rather getting lights that seem to be well made for the price and fit my footprint, and then checking with my meter if they are in the ballpark of what they say, and/or if I need to add more light as I get towards flowering. I really dig the output of the LED's for watts use, and I really dig the lights i've bought. My shed has a 30A circuit, so though I'm not near pushing it yet, I do need to be wary of what kind of load I'm pushing. I do have my old MH/HPS ballast and lamp. I think I'm gonna do the first run with all LED, and then try subbing the HPS(400w) in the second cycle; just to see for myself

I'll be talking to a friend today or tomorrow who was selling LED grow lights for years. He bailed when the Chinese started jumping in and affecting the price point. He is pretty up on all the technology and good to talk to about what really matters. I'm gonna show him my two lights and see what he thinks for coverage. Right now I have a 200 and a 100, both from Maxsisun. I'm thinking of moving the 100 to the small veg room of my tent and then replacing that with a 150.

Onward and upward!

Nwtexan said:

I totally get where you are coming from, and I naturally tend to find things that work and not get into the minutia.

When I grew before I was using MH and MPS and messing around with Hydro.

This time, I am jumping into the LED world, which I think is really cool. In trying to figure out how best to cover my room and how to maximize my assets(light vs electricity) I have naturally done some reading and studying. It's hard to break through the crust of internet "knowledge" to what is really going on. There have been a few pretty extensive studies on light and yield. I'm sure they have been debated ad nauseam on the forums. They give some pretty direct correlations. I'm not basing much on any manufacturers data, rather getting lights that seem to be well made for the price and fit my footprint, and then checking with my meter if they are in the ballpark of what they say, and/or if I need to add more light as I get towards flowering. I really dig the output of the LED's for watts use, and I really dig the lights i've bought. My shed has a 30A circuit, so though I'm not near pushing it yet, I do need to be wary of what kind of load I'm pushing. I do have my old MH/HPS ballast and lamp. I think I'm gonna do the first run with all LED, and then try subbing the HPS(400w) in the second cycle; just to see for myself

I'll be talking to a friend today or tomorrow who was selling LED grow lights for years. He bailed when the Chinese started jumping in and affecting the price point. He is pretty up on all the technology and good to talk to about what really matters. I'm gonna show him my two lights and see what he thinks for coverage. Right now I have a 200 and a 100, both from Maxsisun. I'm thinking of moving the 100 to the small veg room of my tent and then replacing that with a 150.

Onward and upward!

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for seedlings i woulndt give more than 100micro moles
been a while since i didnt sprout a seed, but for clones you dont want more than 70micromoles the first days
300micro moles is too much, the plant will get stunted and stressed

kingromano said:

for seedlings i woulndt give more than 100micro moles
been a while since i didnt sprout a seed, but for clones you dont want more than 70micromoles the first days
300micro moles is too much, the plant will get stunted and stressed

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I'll back the lights off a bit. Again, so much conflicting info. I do like the ability to dim the light, using less electricity as opposed to moving the light around. Most of the pages I was reading were recommending anywhere from 200-400. I'll let the ladies get a little further down the line before I shine that bright light on them<g

200-400 micro moles is for veg stage

seedling are still in "establishment" stage, making roots
more light will exhaust your seedlings, ideally if you grow in a room you want to light 1 on the 2. beware with dimming, can use prematurely bulbs, give the wrong spectrum etc..

i work with 600hps, first days in the system the cutting are lit by 1 lamp on 4 at the time.
when they are rooted in the medium i start to light 2 lights on the 4.
4 lights on at the same time is for bloom stage when light requirement are the highest

kingromano said:

for seedlings i woulndt give more than 100micro moles
been a while since i didnt sprout a seed, but for clones you dont want more than 70micromoles the first days
300micro moles is too much, the plant will get stunted and stressed

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My god you guys are overthinking this. I do enjoy watching though

jonnynobody said:

My god you guys are overthinking this. I do enjoy watching though

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don't speak of what you don't know

from what I gathered the general numbers are those
-seedling 60/100 umoles
-veg 300/500 umoles
-flower 800/1000
-flower+CO2 around 800/100ppm up to 1500 umoles
more that is not useful to the plant, since the light provided energy can be used and stored up to a certain point.

even after u set ambient temperatures of 30c+ where the cinetic energy of ambient pump plant phytoreactions to the top levels archivable its wasted money in my point of view to supplement more than those levels of energy.

I get my umoles (more or less) from the spec sheet of my 308 lm301b pcb
having a scheme of what umoles I get on a certain amperage
i have the rough estimate
worse thing was that almost every spec sheets has a total umoles emitted value tested in a sphere so not exatly the same output would get to the canopy....
had to dive deep in to inverse square law to have a realistic estimate of my canopy esposition!!

sadly couldn't afford a real par reader...what brand did u get?

The sun is apparently between 900/1500 par depending on variables so to say seedlings etc only needs 300 or whatever clearly is wrong as the sun's par is never that low yet cannabis constantly grows fine.

kingromano said:

don't speak of what you don't know

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Can I see some pictures of your garden? I'd love to see your expertise at work.
Here's mine. I'll probably have to throw it all out because I didn't use a PAR meter. I'm sure one of these days I'll figure it all out. As soon as I get my PAR meter and really dial things in

jonnynobody said:

Can I see some pictures of your garden? I'd love to see your expertise at work.
Here's mine. I'll probably have to throw it all out because I didn't use a PAR meter. I'm sure one of these days I'll figure it all out. As soon as I get my PAR meter and really dial things in
View attachment 4781963 View attachment 4781964 View attachment 4781965 View attachment 4781966 View attachment 4781967

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Mids

nice try at a flex though

bk78 said:

Mids

nice try at a flex though

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Words aren't as effective as pictures. Nice try at making yourself feel like a big man though. Little man syndrome is a way of life for dueche bags like you. I've always assumed it's the fact that people like have had to look up to every other man your entire life to have a conversation that causes your low self esteem, but maybe it's the tiny cock you're packing in your pants that makes the magic happen. Either way I enjoy watching your mental instability flap in the wind. Don't ever change sir. You're the best

jonnynobody said:

Words aren't as effective as pictures. Nice try at making yourself feel like a big man though. Little man syndrome is a way of life for dueche bags like you. I've always assumed it's the fact that people like have had to look up to every other man your entire life to have a conversation that causes your low self esteem, but maybe it's the tiny cock you're packing in your pants that makes the magic happen. Either way I enjoy watching your mental instability flap in the wind. Don't ever change sir. You're the best

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Just like you tried to feel like a big man telling these people what to do. Now get back to your fly by night, bug infested mids grow and try and better yourself instead of typing walls of nonsense with every fucking post you make.

bk78 said:

Just like you tried to feel like a big man telling these people what to do. Now get back to your fly by night, bug infested mids grow and try and better yourself instead of typing walls of nonsense with every fucking post you make.

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Every time I encounter a loser like you I feel obligated to make another donation to planned parenthood. People like you are the poster image for post birth abortions. Fucking loser.

jonnynobody said:

Every time I encounter a loser like you I feel obligated to make another donation to planned parenthood. People like you are the poster image for post birth abortions. Fucking loser.

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Wow!!! Only 2 paragraphs this time?

bk78 said:

Wow!!! Only 2 paragraphs this time?

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Still no pictures. Loser.