I grow cacti under flourescent lights. I have golden barrel, fish hook barrel, old man cactus, and several other cacti and succulents that I dont know the names of under lights. I built a light stand out of pvc and attached a 4' shop light to it with two cool natural sunshine bulbs that I got from Home Depot for $7 each. I keep the light on 14 hours a day. They have thrived for the last 2 or 3 years using this set up.

In principle yes, but you will get very high electricity bill + installation costs. Unfortunately I have not heard of anyone doing it, so I cannot tell what would happen if someone tried really hard and did not care about the costs. Most people ask about the most suitable lamps for growing seedlings, but that is another matter. Seedlings do not require much light and are often grown under e.g. fluorescent tubes, but that is too weak for adult plants.

It is difficult to install and maintain the large number of lamps that is required if you want to mimic sunlight to the extent that it becomes suitable for adult desert cacti. Maybe if you use an insane number of tubes, but that sounds impractical. I have seen other types of light sources been used for plants, like xenon lamps, but you'll need a lot of them too. Professional growers of ordinary plants sometimes us sodium lamps (big, heavy and very hot), but I doubt that even they are suitable for the kind of cacti that you want to grow.

Interesting, rambler24. Do you have a recent picture of your barrel cacti?

I think that most cactus species will "tolerate" poor light probably for a few years..but eventually they will begin to look unnatural: reduced spination, muted colors, etc. These plants have evolved to cope with some brutal conditions, so how can anyone expect them to mimic that under weak lights, among other things? Standard fluorescent lights will not work unless, maybe, the plant is right next to the bulb, which is a difficult if not impossible feat as the plants grow.

High intensity artificial lights should be OK for long term growth - things like high wattage HID lamps or some of the newer LED or CFL set-ups. But light intensity is not the only important factor.

Seasonal and daily temperature ranges are critical for long-term health. Cooler nights and cooler winters are necessary for most cactus species (except for things like the "tropical" cactus from Brazil). Temperature swings are difficult to duplicate indoors.

It's one thing to keep plants under lights during the winter because it is too cold outside. That is fine. Plants won't suffer. Year-round growth under lights is much more complicated.

x

Good morning everyone. Thank You for the info so far and please keep it coming. If these kind of cacti can sustain for a time that is fine. This is just until I can convert my kitchen and back porch into a quasi sun room /greenhouse. I used to put my plants outside for the spring and summer but the weather here is so unstable, it seems like we have no Spring anymore. I always end up putting them out, bringing them back in and waiting so long until I think it's absolutely safe that it's hardly worth it anymore.

Ah, that should be much easier. Barrel cacti grows slowly, so they are unlikely to etioliate much even if the light levels are low for a while. How long time will the conversion take?

madaxeman

If you use the right potting mix, then you can safely leave most of your plants outside for longer than you think.

I had a bunch of my plants outside all June when it must have rained 20 out of 30 days, without any problems. I leave many plants outside from April until November.

I'm not telling you not to be cautious - but you can try and push the limit with a few plants and see how they respond.

x

xerophyte

I do have a few outside that would not absolutely break my heart if I lost. Unfortunately my collection mostly consists of some of the most rot prone species there are. Currently I use a soil mix from Cactus Jungle and it is the best I have found to date. Of course our mail lady thinks I'm crazy for having boxes of "dirt" sent to me.

tjicken

The sun room part will be structurally complete by late fall. Right now I am in the planning stages and am pricing different building materials. I am building this with my own two hands so I am only limited by my imagination so the possibilities are endless. I think this is going to be so cool my wife may actually finally accept this crazy cactus obsession of mine. I still want to find a suitable artificial lighting method so I can have a cactus here and there throughout the house as a sculptural showpiece.

hello madaxeman I am looking to find the best grow lights for cactus as well i leave my cactus out from june to october first week then bring them in but I am looking for lighting for winter ill be checking here for a answer i heard metal halide lights work well but im not clear on that .hope you and I find a answer

Hi callicarpa89,
Yes I hope we find the answer also and I will be happy to share with you whatever info I may find. Yes there does seem to be a consensus that the halide systems would work but depending on how many you are using you could be looking at a staggering electric bill not to mention the enormous amount of heat they throw off. Check out the Urban Garden Magazine website, there is a link on there on growing under lights with lots of great info.

Why don't you try one of the many types of Cereoid Euphorbias as indoor showpieces - they are much more tolerant of the lower light and constant temperatures that are found indoors.

A 1500 Metal Halide HID lamp placed about 2 feet from plants provides adequate light for many species.

x

Thanks x ... pretty cool stuff. When my wife leaves me for starting to collect succulents in addition to cacti, I'll send her your way. OK? OK :). One question ... are these pet friendly? I could be totally wrong but I think I remember reading somewhere that Euphorbias have poison or caustic sap. The reason I ask is we have cats who like to try and take a bite out of and sample everything.

I'm not sure the sap is poisonous if ingested, but I know that it is a skin irritant. I do not know how a hungry cat would respond to a Euphorbia...hopefully someone else here can help.