lighting

[Bobble]

Im looking at bringing in my single plant that is doing well outside. Im going to put it on a 12/12 lighting. what size lumens should I use. I heard 5000 lumens

 

[az2000]

Im looking at bringing in my single plant that is doing well outside. Im going to put it on a 12/12 lighting. what size lumens should I use. I heard 5000 lumens

How large is your plant (width x depth? height?). A picture might help.

Lumens is a measurement of all the light emitted (in all directions). It requires a very expensive "integrating sphere" to measure. Typically, when people say lumens, they mean *lux*. That's the amount of lumen light falling on a specific surface. You can buy a lux meter on Amazon for $20 USD. (I have a Sunche HS1010.).

Ex. 5000 lumens would be like three 16w (100w-equiv) household LED lightbulbs. But, since those are omnidirectional, only 2000 lux would fall on the plant. Most LED lightbulbs have their LEDs surface-mounted to the base, all facing one direction. If you cut the diffusion globe off with a hacksaw, they instantly become directional. Much, much more of that 5000 lumens will land on the desired target as lux (without using reflectors, which add loss compared to light that's already directional.).

Typically plants see light as PAR, not the same as the lumen light we see with our eyes. (But, PAR meters cost $400-$600 USD.). Cannabis is said to need 300 ppfd (the amount of PAR light falling on a surface, like lux is to lumen light) as seedlings. 600 ppfd in veg. 900ppfd in flower.

You can't really convert ppfd to lux because it's two different kinds of light. 50,000 lux of HPS has a different ppfd reading than 50,000 lux of flourescent light, or blurple LED light, etc. Lux is what you can see with your eyes. Ppfd is what the plant sees. Within a single category of light, using lux as a proxy for ppfd can be reliable enough.

I've been measuring some household LED lightbulbs, warm white. What I find is 1 ppfd = 50-55 lux. So, that's Seedings = 15,750 lux. Veg = 31,500. Flower = 47,250.

Maybe you heard 50,000 lumens (measured as lux)? But, it depends on the light source. HPS requires (I've read) 70,000. Very efficient LED might be 30,000. (I don't now.).

You can rig up globeless lightbulbs. I've grown cannabis that way (from seedling to harvest), twice. (I often use the lightbulbs as supplemental sidelight.). You need about 30w/sq ft (that's another way to look at the amount of light within a category of light. HPS, or example, is often run at 50-70w/sq ft.).

Anyway, if you could show a photo of the plant with something for scale, or could say what the plant's footprint is (width x depth, height), I'm sure there are plenty of options. Just need to know how much area you need to cover, and how much intensity/penetration (or sidelight).

 

[Bobble]

 

[az2000]

Looks like about 2.5' in all directions?

You could use 187w of household LED lightbulbs (30w/sq ft, 1:1 ratio of warm 2700k & daylight 5000k). That could be challenging, arranging some 19w flood lights from the top, and 9w bulbs around the side. But, you'd get good coverage.

Or, 312w (50w/sq ft) inexpensive Amazon LED grow-light fixture. If you could break that purchase into 3-4 fixtues, that would give you better coverage than all the watts at the top (one fixture). You could cantalever them around the top. I think anytime you can make the light less intense and spread more around (closer), it's a huge improvement in efficiency.

I'm not involved with LED grow-light fixtures (just the household bulbs). Maybe someone can recommend something. (I like CMH LEC 315 for a 3x3 space. But, that would cost more to get into, and be more light than you need.).