I would lean towards t8 because they'll require less vertical space for haworthias. You can put them right against the bulbs with no ill effects, provided the setup is in a cool area, with some air movement. They've stayed in shape, even with 3500k bulbs. This year I replaced them with 6500k bulbs though. The t8 gets just warm enough that I don't have to worry about the occasional deep freeze we get.

This is how I'm set up, anyway. I use my T5HO panel for full-sun plants in winter.

Pagan

Thanks for the response. What's the average temperature of the room you keep stuff in? I'm in Chicago, and would be worried about not keeping my stuff in a room inside of the house. I currently keep things in my girlfriend's sun room, but I could foresee times when that dips below 30.

T-5 bulb is smaller sized in diameter than a T-8 What your looking for is the K coloring of each bulb and the total wattage if using more than one bulb in a wider fixture.

Wattge is heat when asking about bulb warmth concerns Heat is produced by bulb wattage and/or it's equivalent wattage.

Example A normal CFL 60 watt bulb puts out less heat than a normal 70 W CFL bulb which provides less heat than a normal 100 W CFL bulb

A 13 watt CFL that's equivalent to a 60 W puts out very close to the same heat as a normal 60 W CFL bulb Increased heat would also rise as the wattage equivalents bulb is increased.

The closer to the bulb a plant is the more heat and brightness that plant will feel and scene.Distance from a bulb is also a concern to far away they may become oddly ill in appearance to close to a warmer bulb they may at times dry quicker than one may think leading to possible burn, leaf shape distortion and/or desired or natural coloring and or over watering to cool.

Considering that the only difference is the size of the bulb you can find a T-5 cfl that provides the same lighting, K coloring The only difference is between T-5 and T-8 is the plug size Often times T-5 are smaller making them lighter in weight.

My winter plant shelves are in an unheated basement. It never freezes but it goes down to as low as 5C at night. So, I keep my pachypodiums at the bottom of the shelves where it is colder, haworthias in the middle and at the very top, I keep my adeniums. With the light panel below sending up heat, the haworthias are never below 10C even if the rest of the basement is colder. My shelves are also covered on three sides with thick cardboard that I painted white to better distribute the light (I just zip-tied it to the shelf frame). I have more sensitive plants that are upstairs on window sills, too.

This guy keeps his haworthias in a heated greenhouse and he considers 16C to be warm and so he keeps watering them twice a month even in winter. I use his cultivation methods as a benchmark.

Pagan

P.S. Oh! If you are up to it and the sun room gets enough sun, you can try using water barrels as passive heaters. I have no experience in this but it's an interesting area of research.

T.S.

Read thru this thread by Kevin (ewwmayo); he uses T5HO, also grows lots of haws. His plants are in exceptional shape. Maybe you'll find some helpful info:

-click me please-

I was planning on using 6500K either way.
I was under the impression that T5 are more efficient in terms of lumens vs wattage, compared to T8. The upfront costs are a bit more, upfront.

Rina, I've been reading through a lot of the posts/comments from Mayo. He has a great collection/setup. But, he's also growing a much wider variety of plants than I am. The echeverias would require a higher output bulb, which I'm not 100% convinced I need for Haworthias.

Pagan is giving you very good advice, and from personal experience. IIRC, Kevin keeps haws on outer 'edges' of the lights where the output slightly diminishes - hope I am saying it right!

I have only experience with CFL light bulbs which I still have lots of, and have been using for last 3years for all my plants. I also have wider variety and some may not get as much as they would like - but any etiolation is considerably less than it was before the lights (I used to keep them in often used, heated sunroom with glassed south wall - light was still not quite enough in Toronto, Canada). But the few haws I have always did fine under the CFL (min 23W=100w, some higher, all are 6500k). These are probably least expensive - initial cost and consumption.

Pagan, appreciate the response. Perhaps I might look into one T5 panel to cover the agave and echeveria that I have + provide heat, like you suggested. Neither are worth too much money, so I have to balance out cost of plant vs. cost of equipment/electricity.

The Haworthias, OTOH...Those are my primary focus.

T5 will provide slightly less heat (but same light) as T8. T5HO ("high output"), on the other hand, provide about twice as much light per bulb, and noticeably more heat (not twice as much, though, since they are a bit more efficient than T8 for the amount of light).

I think either work, which is definitely represented in all the posts above.

Here is a few months old photo of about 60-70 Haworthia under 2xT5HO and about 50 under 1xT5HO.

The upper setup is where I'm growing most of that Haworthia I've posted photos of lately, for an idea of growth/color/etc.

The lower setup is for not-yet-fully-established plants and will get a second single lamp fixture sometime late fall or winter.

If you like your Haworthia greener than reddish/purplish than you could use probably 30% less light fixtures/electricity and save money there.

Total cost of lights of the above was around $150 CAD plus electricity. For electricity, I created a spreadsheet with my seasonal on hours vs local hourly time of use pricing.

I totally agree with Pagan that LEDs are not really that economical yet.

One of my biggest costs is running air circulation fans, so colder locations are beneficial. I'd put my plants in the basement to save a little money but it's nowhere near as enjoyable as hanging out in the loft or outside.

Rina's CFLs are 23w which is not that different from a T8 or T5. About half a T5HO. Her plants look really nice too.

Thanks for the response!
Trying to figure out my rack setup. One is 36" wide, but I can safely have overhang for both the lights and tray.

Hmm, so each each of the light setups runs about $50. If I have six trays, the whole thing might be about $300, then electricity for fans. Oooof. Quite the expensive hobby I picked up.

Any suggestions on brands for the fixtures/bulbs?

Kevin - thank you...my plants are good for the conditions they are growing in :)

The CFL lightbulbs I use are in strip 'bars' (kind used in bathrooms). They are shiny, so there is some reflection like from a reflector. These bars come in 3,4,5' lengths (probably longer too). I bought bunch of them from restore, they cost $3-$7 each. Bulbs (23W) are under $20 for box of 6. I also made 'racks' of my own, using sockets installed on couple of 2x2. I'll keep using them until I run out of bulbs...I didn't use fans as my plant room (in the basement) is cooler than Kevin's loft - but it definitely is not as nice as Kevin's loft :)

Yeah, fixtures are surprisingly expensive. If you're OK with wiring a cord on yourself, you can save quite a bit of money by keeping an eye on Craigslist (or a saved search to alert you). After waiting for a couple months, I ended up getting a six-bulb T5HO fixture for $20, from a lighting contractor who'd been hired to replace all the lights in a warehouse and wanted to get rid of the existing lights. (The rest of the lights were T8, but there was one T5HO, which he didn't originally know about but still sold me for $20 once we discovered it.)

I had to attach my own cord (so add another $10 for an extension cord to cut open and attach), and had to provide my own chain to hang them, but still a much better deal than new. (Came with the bulbs in it, too!)

I think I remember someone here saying they got their lights similarly from a general contractor they knew, so if you know anyone who does lighting work they may also be a good source.

One caveat: you may also see T12 fixtures this way (or even new!). In my opinion, even though they are cheap, they aren't worth it: the bulbs are being phased out (or already are phased out?) similar to incandescents, due to not being efficient enough, so finding new ones is tough and will only get tougher. (Plus, it'll cost you more in electricity, probably enough in a year to offset the higher cost of T8.)

Here's how I will arrange it. Two 21" trays on a 36" shelf. I can probably fit four total trays (so, two levels) on this particular one. Will probably get another one that's the same size, maybe larger. How many bulbs would I need per shelf/level?

I'm only estimating the depth of these shelves but it looks like the thing can only fit two singles, mounted side by side. Or, a 2-bulb fixture, per shelf level. Plug-in fixtures are usually bulky so if you do not mind wiring things yourself, I'd get hardwired ones since they're more low-profile in general. Plus they are cheaper.

P

I think the depth is about 13.5". Do you think two bulbs per shelf would be enough for the plants? Would this impact whether I should get T5H0 vs T8?

I'm a bit confused about hardwired vs. plug-in.

Yes, I think 2 per shelf will be enough. If this was my shelf, I would be fine with T8s, I'll just put them close to the bulbs, adjusting individually as you go.

Plug-in fixtures are those shop lights with hoods and power cable and plug and some have switches. They hang down about 5 to 8 inches. Hardwired ones are bare light fixtures typically screwed directly into the ceiling that are then connected to the circuit--you'll have to wire them yourself, i.e. splice your own power cable and plug.

This is going to sound weird but try to skimp, if this is your first winter with these plants. Go on Freecycle. Chances are you will change your strategy about a lot of things.

What zone are you in, anyway? How long is your winter?

Pagan

Ah, got it. Thanks for the explanation about the difference. I'll probably just grab the plug-in noes.

I'm in Chicago, so the winter is going to be lonnggggg/cold. FYI, I received/helped someone sell their succulent collection and I earned a few hundred dollars from that + the stuff I've been selling lately. So, I'm fine with spending less than $300 to get this going. I intend to sell a lot of the pups once spring rolls around, so hopefully I can recuperate some of that money.

Update: I'm about three months into using high output T5 on my haworthias. The older/established plants are handling the high output just fine, but it does seem that certain plants would prefer less light. With the setup I have, there is the option to only use one of the two lights. I think I will opt to do that for now.

Has anyone found high-output lights to be too strong for certain species?

Some of my Haworthia are stuck on the fringes permanently. =)

Yes, TSC. Some haworthias like H. venosa var tesselata very easily turns all red and wrinkled under too much light (it will do that too with too much water, too much heat, too much cold) while some, like H. bayeri will turn red much slower which is stunning but after a while it will start to desiccate as well. All the maughannis will just shrug everything off. I've never been able to turn my H. koelmaniorum var. koelmaniorum green no matter what kind of light I have it under.

In winter, haworthias don't really give you much choice but to know them individually. I imagine variegated ones (which I don't have) will be even more "talkative".

Pagan