Growing Succulents and Cacti Under LEDs

So this is a non-cannabis question, but I figured you folks would have a lot of knowledge in the indoor growing department. About a year ago, I moved and brought my collection of succulents and cacti with me. Unfortunately the only space I could carve out for them in the new place was in the back room in our finished basement. There's very little natural light down there, so for the past year I've been growing them under two Dr. Bigg 1000w fixtures:

Dr. Bigg Fixture

They've done pretty well and are certainly doing better than I thought they would with only artificial light. But I'm wondering if maybe they'd do even better if I added a third light or upgraded to something else. The plants are Crassula sp (jades), Pachypodium, Euphorbia and Cereus, all 18" - 40" in height. They are occupying a space that is 72" x 20". Would a third fixture help? Or is there another lighting option I'm overlooking?

Thanks in advance!

That fixture may be working ok for you and it's probably just about right for the application (the fine print is 110w, not 1000 though), and if the plants are doing well, it sounds like you're just fine.

I have a similarly odd sized space (tent, 33"x60") and I run three smaller lamps (225w each). All three have dimmers so I can adjust accordingly, but they provide even light across the whole space.

I don't know that with succulents you need a whole ton of intense light though, I know mine do well on windowsills that aren't all that well lit...but I'm sure there's some document somewhere that can tell you the exact PPFD and from there you should be able to measure what you're getting.

Thanks, LEG. The jades and Euphorbia seem to be doing well, but the Pachypodium and totem pole cactus are not growing nearly as quickly as they did in the bright window in the old apartment. Need to do a little more research!

CanOfGizzards said:

Thanks, LEG. The jades and Euphorbia seem to be doing well, but the Pachypodium and totem pole cactus are not growing nearly as quickly as they did in the bright window in the old apartment. Need to do a little more research!

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PPFD Levels for Ornamentals and Others

So yeah, you're not looking at too much light...Somewhere in the 100-200umol range.

Download Photone and get the right light profile, and even if it's not super accurate with your phone, it will give you a good idea of what you're aiming for. Most of us doing cannabis are using 100-300 for seedlings and up to 1000umol in flower later on. You don't really need that kind of firepower.

Seems like your cacti or a slower grower or two could use a bit more, so adjust the lighting height (lower the light) for those so they get a bit stronger light. You should be solid with the two 110w lights you have.

Great info - thanks very much!

Just downloaded and checked with Photone... I'm getting PPFD readings that are way high. Anywhere from 280 at the height of the shortest plants to 580 on the taller ones. The lights are about 24-30" above the plants. I'm using a diffuser paper around my phone's lens... Could these readings be wildly inaccurate or do I need LESS light and not more?

CanOfGizzards said:

Just downloaded and checked with Photone... I'm getting PPFD readings that are way high. Anywhere from 280 at the height of the shortest plants to 580 on the taller ones. The lights are about 24-30" above the plants. I'm using a diffuser paper around my phone's lens... Could these readings be wildly inaccurate or do I need LESS light and not more?

Click to expand...

Photone really depends on your phone hardware. I know with my iPhone XS Max, it ranged from about 4%-8% off from my Phantom Photobio quantum meter, which is pretty good. I'd expect in most cases it's probably within about 10%. With 110w lights, those numbers are probably about right and not a surprise though.

It's sort of a choose your own adventure...you could try to adjust your brightness on part or all and see what happens. If they don't like it, bring it back.

Can these lights generally be put on dimmer switches? I hadn't thought of that.

CanOfGizzards said:

Can these lights generally be put on dimmer switches? I hadn't thought of that.

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Not generally (they're not just lights, they've got drivers built in, though some can use out-board dimmers). you're better off just lifting them up to get lower PPFD. Buy some cheapo ratchet cords and you'll be able to raise/lower them at will to adjust. I use them for not only my lights, but also holding my fans (now hung) as well as other things in my tent as well as the lights I use for germination/seedlings outside the tent.



I adjust height often (as well as dealing with the dimmers that are on-board on my lights).

...and the lights work just as well for all sorts of plants.

Hot peppers, Tomatoes & a few sativas:


a week later, after I went away on a trip:


The tomatoes loved it so much they stretched about a foot and a half and buried the hot peppers.

Haha - that's awesome. I've got the lights as high up as they'll go, so I may need to put the plants on a lower table or on the floor. OK, got some thinking to do! Thanks for your help!

OK... The plants are on a cabinet that weighs about 8 million lbs and serves multiple purposes, so I'd rather not move it and lower the plants... What if I were to remove these lights and get a few smaller fixtures so that I could keep the plants where they are? Could you recommend something that might be a better fit? I've attached a pic of current setup (well current as of yesterday - I moved the Pachypodium from the pedestal up to the cabinet since it nssds more light than the others. I could do a row of three or four smaller fixtures in place of the two 110w guys. Thoughts?

Also - all of these plants were pruned back pretty severely prior to our recent move. They Pachypodium was over 6 ft tall but had to chop it to fit in the car!

Those COBs are pretty tiny as it is...I honestly don't know of anything that would be smaller.

OK. Maybe I'll post on a succulents/cacti forum. If the higher PPFD readings don't cause any harm, maybe I'll be ok with it as is. Maybe?