Another Lighting Question

[grandmapenguin]

Even though I post a lot I am still such a Newbie in the Lighting department.

Our Orchid group had a talk on lighting today and even though we had questions I have come away confused.

One thing I found about was that the bulbs don't last until they burn out. They should be changed. One recommendation was every 6 months. Can I hear how often our Members change theirs?

Also what type of bulbs are you using? I have the typical Shop Light Fixture with two fluorescent bulbs. One is a Gro Lux Aquarium bulb and the other is a Cool White. My plants are doing beautifully under them but now I'm thinking what if Could I be using something more advantageous for the plants

Would love to hear any ideas since all the plants are indoors for the Winter and I won two in the Raffle today so I need the lights.
Terry

[Brooke]

I always used the cool bulbs, which has more lumens than a warm bulb when I grew under fluoros. I did not have a problem growing and blooming lower light plants under all cool bulbs. I wanted as many lumens I could get inside. They were on 16 and off 8 hours per day.

The strongest light, about 1000 fc's will be in the middle of the tube with the end of the tubes measuring 600 fc's. Yes the tubes will start to lose intensity from the first time you turn them on and by the end of six months the fc's drop drastically and should be replaced.

I started growing under lights a long time before I grew orchids and found the switch to orchids easy. I always grew my annuals from seed and started them early enough to have big chunky blooming plants when it was safe to plant outside. Phals and Paphs do great under lights and will bloom freely but higher light orchids will grow but blooming will depend on the particular cultivar.

What did you win in the raffle?

Brooke

[kmarch]

My understanding is that shortly before they burn out the output of flourescent tubes, the kind you use in shop lights, drops significantly. I read somewhere the recommended number of weeks oyu should use the tube then replace it even if it is not burned out but I can't remember what that was now. Brooke's probably right but it seemed like it was less than 6 months, the recommendation I read.

When I used shop lights I used one cool bulb and one warm bulb. Using one of each like this gives you almost the exact same spectrum of light as a grow light only at about half the cost. I usually replaced my bulbs when I noticed them flickering. If I didn't catch them then they burned out and I replaced them then. I never experienced any detrimental results.

[mayres]

They do start loosing a small percentage almost immediately, but not as much as some people might have you believe. Figures I've read say 10% loss at 3-4000 hours (which is about a half year at 16 hours per day) and 20% loss at 7000 hours - about a year. So, if you are only getting 1000 footcandles in the middle of your T12's (near the bulb), that is going to degenerate to 900 at a half year and 800 at a year. In a business setting where we need every lumen/footcandle possible to zap bugs (which also use fluorescent fixtures) we change ours every 6 months. I've checked mine with a light meter at home and the numbers seem to stack up with the figures noted. A yearly change seems to be adequate unless you are really needing every single footcandle you can get - and actually if you need to go there maybe you should consider T5's? Just a thought?

[mehitabel]

If you have more than one or two lights, it's very expensive, even prohibitive to change them every 6 months. Even changing the bulbs every year is expensive.

I make no claim to expertise on lights, tho I've used them successfully for many years for a variety of flowering plants, and more recently with orchids. What I have read (and what I finally decided to use in making decisions of when to buy new bulbs) is this:

The lights do deteriorate with the number of times they are turned off and on, and the total deterioration over a period of, say, one year, is considerable. This might suggest renewing every year. However, the benefit of making this expensive yearly changeover is very much less than you would expect, because...

Because the deterioration is not a straight-line gradual decline. It's more like this \__ , with most of the falloff in intensity occurring in the first few weeks of using the bulb. After that, the rate of deterioration slows down markedly. So the loss of intensity during year 2 is very little-- much less than you would expect from the loss in year 1. And when you do replace the bulb, the benefit of the new bulb after the first month is less than you would expect if you envision a straight-line gradual decline in light quality.

I would definitely not change oftener than once a year, and you might find you can easily stretch it to two.

[grandmapenguin]

Thanks for the responses. I am now considering the T-5s. My DS came up and suggested this may be a more economical way to go.

I won a Paph and a Don Wimber Phrag. I have one already but I love them so now I have two.

[mayres]

I'm not sure that they will be more eonomical, but you will most certainly be happy with the increased lighting options. Keep in mind you will get some heat buildup too that you didn't note from T12 shoplights. I love my T5's and certainly recommend them - but they are not cheap - fixtures or bulbs........

[grandmapenguin]

I do run a fan on the same timer I light the plants. Thnaks for the suggestions.
Terry

[exasperatus2002]

Thanks for the good information.

[grandmapenguin]

Well, I finally got my T-5 setup
I can just see those flowers ready to POP. LOL

It took some redoing. I had to move all the Phals to the Breakfast room bay window. I felt the lighting would be too intense.
Lighting experts; please does this look like I have enough distance between the top of the leaves and the bulbs I don't have any low light Chids in there. That's an almost leafless Meyers Lemon tree in the foreground. It definitely needs this light. I do have fan running all the time the lights are on and they are on 16 hours at present. Should I decrease or increase this at any time

In my readings Gardener's Supply said T-5s burned 45% less energy than regular fluorescents.

[mehitabel]

Congrats on your new T5 set up. It's a great choice. I love T5s. I don't know if they use less electricity, but they give a lot more light-- I've read it's twice as much light as T8s. I also think they are better looking all around.

I don't think your lights are too close at all. I'd say it's about the right distance for starting out. If they are all high-light plants and orchids, you may want to lower the light an inch or so a week for a couple of weeks. The distance you have there is about what I use for my phals that aren't in spike, or maybe I even have it a bit closer. For high light plants, I would try to have the lights no more than 8-10" above.

I use the principle "give as much light as you can without burning".

[mayres]

I'll second the comments of mehitabel - looks good!
Keep in mind a important factor to consider regarding the less energy consumed - they will NOT use less energy than the shoplights T12 or T8 with the same number of tubes - but will create more heat and use more energy. BUT they are making lots more light too. The less energy that is being referenced in adds and reference paperwork is in reference to comparing same light output.

[Brooke]

It looks great

Don't increase the time - the experts say plants need to have minimum 8 hours of dark to "eat" the food the made during the light hours. Growing inside we never shortened the time but some people do.

Brooke