How low can I hang household Led

[Refugee47]

I have a couple high lumens Led bulbs i wanna hang over my 3 day old seedling just not sure of the proper hanging height. Any suggestions would be appreciated. Bulbs are 50 watt 5000 lumens 5000k

 

[Refugee47]

Forgot to mention after hours of use I did heat test and there was zero heat to be felt anywhere around the bulb.

 

[aridbud]

Three day old seedlings, no heat from bulb....you can hang as close as 12" (2.54 cm) above. Good luck with your project!!

 

[f-e]

That's quite a big lamp. Not very efficient but still 5000 lumens is going to flower a foot on it's own.

I would be cautious at 12" unless you leave the globe on

 

[Refugee47]

That's quite a big lamp. Not very efficient but still 5000 lumens is going to flower a foot on it's own.

I would be cautious at 12" unless you leave the globe on

Yes I will be leaving the globe on. I don't plan on flowering with it just need something to get the seedling going until its mature enough for my 315cmh. Someone told me the 315cmh would cause stretching and I'd be better off with a led bulb or cfl for the first couple weeks.

 

[f-e]

Yeah you need very little light to start seeds. I find humidity the thing that regulates stretch for mine. I like it on the low side but still expect to bury some stem when I pot up. That can be handy for water usage. Allowing you to just half fill a pot with the seedling low in it. Than as water demand increases you put in more substrate. Everything below them first two little pillow like leaves (cotyledons) is a root. I'm not burying stem.

The low RH will also help with Ca uptake, as the LED is a cold light. So you need a warm work space and the lower RH to help it transpire

 

[noknees]

hard to imagine how one of those 50W could be the right tool for the job. these are good though.

Three day old seedlings, no heat from bulb....you can hang as close as 12" (2.54 cm) above.

 

[aridbud]

hard to imagine how one of those 50W could be the right tool for the job. these are good though.


Poster said "a few" lamp bulbs equivalent of 300w equiv./50w. Hell, back in the day (late 70's), we used fluoro duo shop lights and had some pretty solid harvests.

For getting seedlings growing, those will work.

 

[Refugee47]

Yeah you need very little light to start seeds. I find humidity the thing that regulates stretch for mine. I like it on the low side but still expect to bury some stem when I pot up. That can be handy for water usage. Allowing you to just half fill a pot with the seedling low in it. Than as water demand increases you put in more substrate. Everything below them first two little pillow like leaves (cotyledons) is a root. I'm not burying stem.

The low RH will also help with Ca uptake, as the LED is a cold light. So you need a warm work space and the lower RH to help it transpire

Interesting theory. You think low humidity is okay for young seedlings ? How low we talking ? I try to keep mine between 50-60% with temp between 76-80. I'm getting some condensation today so I thought about turning off the humidifier but that goes against everything you read in the books about seedling/veg humidity levels.

 

[Refugee47]

hard to imagine how one of those 50W could be the right tool for the job. these are good though.


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Idk how those weak cfl's can work better than powerful led bulbs but I'm try them next time. I got a few of these a while ago and never used them. I work at lowes on weekend so I'm always grabbing clearance lights.

 

[noknees]

Idk how those weak cfl's can work better than powerful led bulbs but I'm try them next time. I got a few of these a while ago and never used them. I work at lowes on weekend so I'm always grabbing clearance lights.

it's not that they're weak. they're the right tool for the job. close to idiot-proof. however, it's difficult to describe the level of overkill those 50 watt bulbs are.

a farce, perhaps? m1 tank in a Starbucks drive-thru?

seriously, don't light burn your babies with those.

 

[f-e]

The CFL has been superseded by the LED. That doesn't stop them from working though, if you already have them. A 100w equivalent should have no problem over a seed tray. Using just 20w. An LED could do the same job with about 12w. The point Noknees is making is that both the 20w cfl and 12w led are about a third as bright as the 50w lamp in use. 50w is a bit big to actually flower a seed tray. Seedlings don't want that demand placed upon them.

I might still use the 50 because it's also a heat source. That dome disperses the light very effectively so it might not be sending much more light straight down than an opened up 100w equivalent. That dome is a big player.

77-80f is nice and at that I would be happy enough around 50%. We have to keep on the low side to get the transpiration those vpd graphs expect us to achieve. I did find a realistic one once... but lost it.


Without pics I'm unsure if you have seeds or seedlings or something you could call a plantlet. So any advice we give is a bit of a stab in the dark

 

[Refugee47]

The CFL has been superseded by the LED. That doesn't stop them from working though, if you already have them. A 100w equivalent should have no problem over a seed tray. Using just 20w. An LED could do the same job with about 12w. The point Noknees is making is that both the 20w cfl and 12w led are about a third as bright as the 50w lamp in use. 50w is a bit big to actually flower a seed tray. Seedlings don't want that demand placed upon them.

I might still use the 50 because it's also a heat source. That dome disperses the light very effectively so it might not be sending much more light straight down than an opened up 100w equivalent. That dome is a big player.

77-80f is nice and at that I would be happy enough around 50%. We have to keep on the low side to get the transpiration those vpd graphs expect us to achieve. I did find a realistic one once... but lost it.


Without pics I'm unsure if you have seeds or seedlings or something you could call a plantlet. So any advice we give is a bit of a stab in the dark

Thank you very much for the information. This forum has been more help in two days than the whole internet in weeks of me searching for answers about LED/CFL lighting.