IMO, there's really no practical reason to use the expensive full-spectrum lights. Go get some that are about 5000K and that will work fine. I actually use half 5000K and half 4100K, which gives me something equivalent to something in the middle (really, very little difference).

I'm not at all familiar with how much light it will take for an indoor citrus. My guess is that it will take a lot. In my indoor growing area, I have fluorescents spaced as close as the fixtures allow, and on more than one circuit.

I know you said you had read multiple forums. If it were me, I'd probably go to GardenWeb's Growing Under Lights Forum and ask there. I believe you'd be more likely to find the most people with the best answers there, as compared to say the Citrus Forum, the House Plants Forum, or this forum.

Here is a link that might be useful: GardenWeb's Growing Under Lights Forum

Depends if you just want to keep them alive, or actualy ripen fruit.

Citrus needs a LOT of light, especially sweet ones. Lemons and limes can get by with less, since they're not as high in sugar as oranges and mandarins.

IME you need something in the HID category, 400 watts or better, at least...if you're talking oranges or tangerines. For a lemon or lime you *might* get by with less.

I used a 1000 watt metal halide (just a "regular" one, not a "full spectrum") and for about 2 yrs got a few ripe oranges and grapefruits, until some weird mite killed my trees. They did spend the summer outside as well.

This post was edited by hairmetal4ever on Tue, Dec 3, 13 at 16:25

If by north Texas you mean DFW, you should be able to keep them outside and only bring them in if the temps are forecast to drop below freezing. A few days in the dark garage every now and then isn't going to hurt them. Citrus don't mind cool weather.

That's a good point - your average daily highs/lows are just fine - just bring them in if it's going to be below freezing. In pots any freezing temp is an issue - even if in-ground they can tolerate down into the 20s.

A Chinese restaurant near me has one that flowers and bears a few fruit, not sure of what type of tree and fruit, they are oranges of some sort, the pot is in their window facing south. No supplemented light. This may not be enough info, but that's all I know about it.

Brandon 7,
Thanks for your helpful info. I have read too many forums recommending a myriad of choices, many of which are unavailable here in North Texas. I finally bought some daylight spiral CFL's that claim 5K. Halides cost too much to operate and are too hot. I have no natural light and keep all of my my tropicals in a closed, insulated garage. The temp here in the N. Texas area got down to 14 degrees this week. We still have ice on the ground (four days later). I only allow them outside when the temp. is above 40 degrees. I do expect to get fruit. They bloom in February but in the past they have lost most of their leaves. My tangerine made five fruits and 4 are still on the tree (trying to get sweeter). We shall see how the lighting helps.
They stay outdoors during suitable weather.AGAIN - THANK YOU!!!

Hairmetal4ever
Mine are sweet varieties. I want to keep them healthy during the winter months but expect to ripen fruit as well.

Thanks for the input.

To all,
I left my citrus out a couple of years ago during a "light frost/freeze" and they lost most of their leaves. I don't want to have that happen again. They have been putting on new growth and blossoms in February. Still too cold here in Denton, Texas area to put them outside permanently.

Thanks to all.

To all:

I am still confused!

I went on the website of, 1000bulbs and searched for 5000K CFL bulbs and found what must have been hundreds of qualifying hits as follow:

Wattage-------------------------- 5.0 & Up
Output --------------------------- 5000K Full Spectrum
Lumens-------------------------- 250 & up
Prices---------------------------- $1.27 up to $66.59 ea.

With so many choices, why would anyone choose a costlier bulb if they all put out 5000K?

Someone with substantial knowledge, please advise me.

A 5000K bulb, is a bulb who's maximum output is centered around that frequency. A "full spectrum" plant light is a light that supposedly attempts to put out light over a broad range of frequencies. For growing plants, the full spectrum might be very very very slightly better, but is generally not considered cost effective by most professional growers. If cost is no issues, go for the most exotic light system you can find (not fluorescent, BTW), but if you just want a workable light source, go down to the Home Depot and get some plain normal fluorescent bulbs (somewhere near the 4700K or 5000K range). You can compare fixture costs, bulb costs, bulb life expectancy, bulb efficiency, etc to figure out which type of fluorescents you want to use. I use the standard T12 bulbs with what Home Depot calls shop lights (which are just the plain, normal, inexpensive type of fixture).

For mine I use a couple double shop lights with 40-watt T-12 fluorescent light bulbs in them. These are set for 12 hours.

Then I bump it up with a 1,000 watt metal halide lamp that is on for about 4 hours in mid-day.

Here is a link that might be useful: Metal Halide system

This doesn't have much to do with your citrus, but to give you an idea of the amount of lights needed for say a seed bench, I use 1 T12 bulb per square foot of shelf. So, each 3' x 1.5' shelf, has 3 sets of shop lights (total of 6 bulbs). With the bulbs not far from the seedlings, this ends up giving something close to the amount of light present during typical (averaged) daylight hours in a full-sun location.

For your tree, my above example may have its limits since you can't really place the lights directly over each leaf.