Height of light for seedling?

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bibsoconner

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I have two seedlings, both Alaskan Purple Auto Feminised Seeds from Seedsman. For now, I have one outside (southern california. Currently about 10 hours of daylight and days are getting longer) and one inside with exactly 12 hours of light from a BLOOM PLUS LED Grow Light BP 1000W (which I'm told is really 90W??!!) From the light to the top of the seedling is 14 inches.

I've taken a picture of both side by side. The taller one is the one that is inside. The shorter one is from outside (moved in temporarily for picture day!). I've had (bad) experience with indoor growing before. To my mind, this indoor seedling is repeating what I saw in the past. It seems too tall and "lanky" and will probably fall over at some point. Any comments? Is distance to light too much/little? Should I even be using a light at this point?

I'm told with these Autos I don't have to worry about switching the light from 18/6 to 12/12, hence the 12/12 inside and the 10+ outside (which will steadily increase as spring comes....).
Thanks!
 
Height of light for seedling
GreenGalaxyFarm

GreenGalaxyFarm

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your issue seem lights is too far, seedling is stretching for it
if she falls over she will die cant you support her with something short term
90w isn't enough imo to grow flower, why such small fixture? is heat an issue
 
RootsRuler

RootsRuler

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Cob lux distance watttage


If you don't have one already I suggest you download a LUX app so that you can get a general idea of how much light energy your lamp is putting out. Dedicated PAR light would be even better. As you can see for seedlings and sprouts you want to go very low LUX. I would use the LUX app to determine the light height but this chart will give you a general idea as to how high to hang your light.

Since your light puts out 90w we'll use that as a baseline. I like to give my seedlings and sprouts anywhere from 5,000 to 10,000 LUX depending on what stage they are at in that phase. If we try and average out where I like it that would be 7,500 LUX. The chart says for 7,500 LUX at a 12" height you would need to lower the wattage in your light to around 15 watts. Not sure if your light has a dimmer or if it'll even go down that low. At 45 watts, which is half the wattage your lamp can do, you could hang the light at 30" and hit your LUX goal. If you don't have a dimmer and have to run your light at full power you would need to hang it higher.

Once you have a general idea as far as height you could fine tune it with the LUX app or PAR device.
 
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GreenGalaxyFarm

GreenGalaxyFarm

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@bibsoconner you have access to a lux meter, or have a camera calibrated lux meter app
and watt meter or is the 90w confirmed?
 
BigBlonde

BigBlonde

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The tall one needs more light. More wattage is probably the best solution. The lanky plant can be helped by adding soil around its stem. The plant will send out roots to the added soil.
 
GreenGalaxyFarm

GreenGalaxyFarm

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BigBlonde said:
The tall one needs more light. More wattage is probably the best solution. The lanky plant can be helped by adding soil around its stem. The plant will send out roots to the added soil.
Click to expand...
and would you go 18/6, 20/4 or probable recommend 24h for sprouted seed
 
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bibsoconner

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Just got a lux meter for iPhone. Top of seedling now at 14500. Previously at less than 2000
I didn’t realize that being out of direct light would make such a difference. Here’s a picture showing new seedling position and old position (where pencil case is)
 
Image
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bibsoconner

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GreenGalaxyFarm said:
your issue seem lights is too far, seedling is stretching for it
if she falls over she will die cant you support her with something short term
90w isn't enough imo to grow flower, why such small fixture? is heat an issue
Click to expand...
The light I have is simply because I'm a beginner and this is what I found. It was cheap (Amazon) and I figured I'd play and then buy something else. Do you have a recommendation? Perhaps I should write another thread on light recommendations.
 
GreenGalaxyFarm

GreenGalaxyFarm

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bibsoconner said:
The light I have is simply because I'm a beginner and this is what I found. It was cheap (Amazon) and I figured I'd play and then buy something else. Do you have a recommendation? Perhaps I should write another thread on light recommendations.
Click to expand...
recommend if you want to purchase a light buy the better one you can affort now or after a period of savings. set a budget but get stronger light
 
GreenGalaxyFarm

GreenGalaxyFarm

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bibsoconner said:
Just got a lux meter for iPhone. Top of seedling now at 14500. Previously at less than 2000
I didn’t realize that being out of direct light would make such a difference. Here’s a picture showing new seedling position and old position (where pencil case is)
Click to expand...
you are about 250 ppfd now
what is the light cycle again
is this the same light or did you just move the plant closer
 
BigBlonde

BigBlonde

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bibsoconner said:
Do you have a recommendation?
Click to expand...
Yes, but I'm only amid my second grow under lights. I've been using Viparspectra XS2000 lights. It seems to have been a lucky choice, because they work well. I don't know if they are among the best. I only know that they have worked well for me. They just introduced new versions that have some nice features.

bibsoconner said:
Perhaps I should write another thread on light recommendations.
Click to expand...
You probably would get many recommendations. It might be better to ask how to choose lights. It's a good idea to look through their manuals before buying. Most should have specifications for distance and intensity for the different stages of growth. Viparspectra does.
 
GreenGalaxyFarm

GreenGalaxyFarm

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BigBlonde said:
Yes, but I'm only amid my second grow under lights. I've been using Viparspectra XS2000 lights. It seems to have been a lucky choice, because they work well. I don't know if they are among the best. I only know that they have worked well for me. They just introduced new versions that have some nice features.
Click to expand...
would not suggest anything but bar style led at this stage
 
Madbud

Madbud

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bibsoconner said:
The light I have is simply because I'm a beginner and this is what I found. It was cheap (Amazon) and I figured I'd play and then buy something else. Do you have a recommendation? Perhaps I should write another thread on light recommendations.
Click to expand...
Blue light, blurples, keep them bushy. Plants on the left are under a 135w blurple, on the right a 200w led at about 50%
Image
Image
 
B

bibsoconner

83
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GreenGalaxyFarm said:
you are about 250 ppfd now
what is the light cycle again
is this the same light or did you just move the plant closer
Click to expand...
Just moved plant closer. Actually got it more directly under light which made a huge difference. How do you convert LUX units to ppfd? Light cycle is 12/12 because I have another 2’ plant in veg. I thought with these auto seedlings I could use 12/12? I need the 12/12 for the big guy ad he is not auto.
 
BigBlonde

BigBlonde

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GreenGalaxyFarm said:
would not suggest anything but bar style led at this stage
Click to expand...
They're good, especially for dispersion of the light. Light choice, of course, depends on the size and shape of the grow space. Panel-type lights work well in a smaller grow space.
 
GreenGalaxyFarm

GreenGalaxyFarm

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understand you are growing the autoflower next to the photoperiod using deflected or unused lighting?
maybe get a budget 3x3 and sufficient light for that space for the purpose of your autoflower grows
 
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