LED Bottom Light

BobCajun

BobCajun

Well-Known Member
This pic shows how bottom light with 100w replacement LED bulbs eliminates dim zones entirely, assuming short plants. No more fluff. It's about one per square foot. Each one draws 14 actual watts. That's equal to about 20w of fluorescent, which is ample for healthy plant growth by itself, even if there were no top light. Now the lower canopy from above looks lit up like the top canopy does from below.

If you had a larger grow, with pots on the floor, you could simply sit cheap table lamps between the pots at intervals, with a Y socket in each one for two bulbs (save on lamps). Actually you could also put Y sockets in the first Y socket and have four bubs per lamp. I would leave the diffusers on the bulbs, in case leaves drop on them. I already had mine cut off so I used them as is.

This seems like a good way to increase total wattage without burning the tops. Adding more top light doesn't help that much anyway after a certain point. Bottom light could practically double the yield of a particular floor area, I would think, and also make bud quality a lot more consistent. This would be especially useful for people with plant count limits. Same height, same diameter, more weight.

DSCF0293.JPG
 
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BobCajun said:
This pic shows how bottom light with 100w replacement LED bulbs eliminates dim zones entirely, assuming short plants. No more fluff. It's about one per square foot. Each one draws 14 actual watts. That's equal to about 20w of fluorescent, which is ample for healthy plant growth by itself, even if there were no top light. Now the lower canopy from above looks lit up like the top canopy does from below.

If you had a larger grow, with pots on the floor, you could simply sit cheap table lamps between the pots at intervals, with a Y socket in each one for two bulbs (save on lamps). Actually you could also put Y sockets in the first Y socket and have four bubs per lamp. I would leave the diffusers on the bulbs, in case leaves drop on them. I already had mine cut off so I used them as is.

This seems like a good way to increase total wattage without burning the tops. Adding more top light doesn't help that much anyway after a certain point. Bottom light could practically double the yield of a particular floor area, I would think, and also make bud quality a lot more consistent. This would be especially useful for people with plant count limits. Same height, same diameter, more weight.

View attachment 3987515
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Very nice, but have you tested this for a whole flower run? Or even better, do you have some kinda side by side comparison: a plant grown with your standard top light vs a plant grown with top and bottom light, in order to compare what kind of buddage you get on lower part of the plant?
This is super interesting with all the posibilities of ledstrips.
 
Rocket Soul said:
Very nice, but have you tested this for a whole flower run? Or even better, do you have some kinda side by side comparison: a plant grown with your standard top light vs a plant grown with top and bottom light, in order to compare what kind of buddage you get on lower part of the plant?
This is super interesting with all the posibilities of ledstrips.
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This is the first test run, for the final 3 weeks of flowering. I'll post results then. Strips would work well, but you'd need ones with optics on it, meaning a clear shield, like the fluorescent replacement tubes. Those tubes with better LEDs in them would be good. The ones they sell for general use are only 17w in a 4' tube, so you'd need a few of them. They seem efficient though, 2100 lumens from 17w, so 123 lumens per watt, about the same as the Samsungs of similar color. Those particular ones are by Philips, who also make good LEDs. I guess you'd need a fluorescent ballast to power them though, or appropriate driver, extra expense. The light bulb type are cheap, $7-8 for 14w as opposed to $12 for 17w and you need a driver.

I think this may be my most productive improvement yet. It seems so obvious but I just never thought of it much. The LED bulbs make it practical now, so maybe that's why I did it. Had some extra ones so thought I should use them for something and that came to mind. It worked out perfect so far.
 
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BobCajun said:
This is the first test run, for the final 3 weeks of flowering
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ill bet they finish bigger than usual but an earlier start might yield better results. every time i second crop middle buds they have weight but they still have the popcorn look (albeit large popcorn :lol: ). seems like they can never really catch up from the lack of light early on. same with "downer" branches i stick up thru the scrog. one you get past day 30 its hard to get that density back
 
CobKits said:
ill bet they finish bigger than usual but an earlier start might yield better results. every time i second crop middle buds they have weight but they still have the popcorn look (albeit large popcorn :lol: ). seems like they can never really catch up from the lack of light early on. same with "downer" branches i stick up thru the scrog. one you get past day 30 its hard to get that density back
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So far the bottom ones are still stringy but the strings are getting floppier from their weight. They'll never be normal size, I'm sure, but maybe small solid buds.
 
I think its a waste of power, I mean if your going to do all that; just switch to a vertical style grow.

not to mention the safety reasons. I get nervous when I see power strips with no breakers laying on the floor in tents. let alone open connection LED/cobs.
 
Interesting idea. I have buckets of 100w equivalent led bulbs with the plastic tops sawed off to expose the chips.. Plug them into a power bar and point them up. It would, as SoOLED suggests, add an extra dimension of danger while watering for a soil grower like myself, but who knows? might be cool.

I'll be watching your results.
 
Rusher said:
Interesting idea. I have buckets of 100w equivalent led bulbs with the plastic tops sawed off to expose the chips.. Plug them into a power bar and point them up. It would, as SoOLED suggests, add an extra dimension of danger while watering for a soil grower like myself, but who knows? might be cool.

I'll be watching your results.
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In Y sockets they don't catch as much stuff, because they're angled. I made foil reflectors for them to reflect some light up, they're open on the top part but wrap around the bottom, sort of like a bouquet of flowers. All power bars have breakers of course. BTW if you kept the parts of the diffusers that you cut off, you can scotch tape them back on.
 
Im kinda doing the same thing and ive been a little scared of burning her. 2x300 watt galaxyhydro blurple. 2x36 watt led supplemental light and 1x 12watt red flowering bulb. I think its about 400 true watts of led but its bright af lol. 2.5x3 closet with 1 plant. Hoping to get 4 oz. 8 weeks veg and lst
 

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JimmyTheNewb said:
Im kinda doing the same thing and ive been a little scared of burning her. 2x300 watt galaxyhydro blurple. 2x36 watt led supplemental light and 1x 12watt red flowering bulb. I think its about 400 true watts of led but its bright af lol. 2.5x3 closet with 1 plant. Hoping to get 4 oz. 8 weeks veg and lst
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Looks well lit. Sort of "surround light". That's the good thing about small LED lights, you can put em just about anywhere. I think it will work much better than if they were all on top. Considering the roundish shape of a single plant, surround light is probably the best option. After it gets a big canopy you may need some directly under.
 
Devilsplant said:
Isnt the suncloack specifically for something like this?
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Yes, though it doesn't actually direct light upward from below. It does look like a good product for side lighting though, depending what brand LEDs they use in them. Meanwell drivers anyway and about the average price per wattage that you'll find with commercial grow lights, close to $2 per watt.

Personally I like the LED A19 bulbs, Sylvania/Osram brand. They get very good reviews on hardware store sites, while Noma gets all bad reviews. They burn out within a couple months apparently, so avoid those ones. But the price is less than $1 per watt for the good Sylvanias, the best deal in LEDs available that I know of, including drivers. I've recently seen the 60w replacements for $3 each, 8.5w of LED. That's 35 cents per watt. I guess the 60s are the best deal of all wattages available, probably because they sell the most. You'd need about 9 per square foot. Fairly convenient, makes a nice square shape. Just that socket cost would be a problem if the space was any large size. Need to just solder the wires on or make some kind of multi bulb holder I guess. It's easier with the 100w replacements, 14w actual. Only need 5 of them per square foot. Just not as good a price on them as the 60s.
 
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BobCajun said:
Looks well lit. Sort of "surround light". That's the good thing about small LED lights, you can put em just about anywhere. I think it will work much better than if they were all on top. Considering the roundish shape of a single plant, surround light is probably the best option. After it gets a big canopy you may need some directly under.
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Yea it really is. This is my first plant ever so i have nothing to compare to but i just didnt see the point in blasting the top with to much light and neglecting the bottom half with nothing when i could do like you said and give it surround lighting. Its funny i came across this bc i was just about to make a thread about it myself lol so thanks i hope it works well for us both
 
JimmyTheNewb said:
Yea it really is. This is my first plant ever so i have nothing to compare to but i just didnt see the point in blasting the top with to much light and neglecting the bottom half with nothing when i could do like you said and give it surround lighting. Its funny i came across this bc i was just about to make a thread about it myself lol so thanks i hope it works well for us both
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I guess we need surround-light tents now. Builtin LED panels on the sides. Well I guess not builtin, because then it wouldn't be foldable.
 
JimmyTheNewb said:
Yea it really is. This is my first plant ever so i have nothing to compare to but i just didnt see the point in blasting the top with to much light and neglecting the bottom half with nothing when i could do like you said and give it surround lighting. Its funny i came across this bc i was just about to make a thread about it myself lol so thanks i hope it works well for us both
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I'm misreading this, you are saying that the bottom sides of leafs have photoreactive cells that can use light?

unless I'm reading this all wrong; my understanding of basic leaf/ photosynthesis does not support this theory since respiration or the spongey or whatever is below the cute cells.

side lighting is used to help cover corners that are not getting enough PAR from the main light source. a "bottom" light source might in a tent might reflect, but that's still less efficient: then top or side lighting.
 
Im saying the bottom half of the plant not the bottom side of the leaves. If i light from the top like normal LEDs only penetrate so far so the bottom half of the plant aint getting light. I put leds to where theyd shoot right through the bottom half of the plant so the whole plant is lit up like a xmas tree lol. I am concerned with light burn a little bit
 
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