Cfl Daylight bulbs as grow lights?

[kwarren]

I saw an orchid enthusiast's video on YouTube and noticed he was using the cfl daylight bulbs as a supplemental light source. This bulb gives a slight bluish cast of light and I'm wondering if it truly is beneficial and can be used as a substitute for the incandescent plant grow lights which uses much more wattage. One brand of daylight bulbs states on the box that the light appearance is listed as 5000K on a scale that measures warm to cool light. Another brand has a daylight coolness of 6500K. I do not want to use florescent fixtures with grow tubes, so the cfl daylight bulbs seem like a wonderful idea. Does anyone have any information or uses this type of bulb as an efficient substitute for grow lights? I would really appreciate anyone's knowledge or experience.

[Dante1709]

Daylights are almost always 6500 K..They can definitely be used although some argue that it has too much of a blueish tone to induce flowering, many growers say it's fine..If you can,mix in some sunlight or 'redder' lights (3500 K, maybe?).

But yes, CFLs are much better than incandescents because of the effiency. I did my research before deciding to just get some 24" fluorescents, and from what I heard, they are fine for a few smaller plants or as a spotlight. Look for as many lumens as you can find.

[Bill U.]

I currently use daylight CFL bulbs as grow lights for my orchids as well as my other indoor plants/vegetables.

The bulbs I am using are all 6500K. I have some 100 watt equivalent and one or two 200 watt equivalent bulbs. I think the 40 watt equivalent is roughly 23 watts of actual draw power and easily will put out 800 fc from several inches away. I dont remember the amount of draw for the 200 watt equivalent, but it was less than 75 watts.

I use the stronger one for supplemental lighting for my indoor blueberries, raspberries, and mini rose plants. Using these bulbs in reflectors really helps my plants grow and produce year round.

You shouldn't have too much trouble finding these, but may have to order some of the higher intensity bulbs online because many stores will not stock them on the shelves due to low demand. (I recently bought a new 200 equivalent from Home Depot for less than $10 and had it shipped to the nearest store for free= big savings on shipping cost).

There are also many other threads on artificial lighting here on OB, but I warn you- artificial lighting gets very technical very fast.

Let us know if you have more questions!

[kwarren]

Thank you both for taking your time and sharing your knowledge and experience on this subject. I really appreciate it! I may go with the 60 w. equivalent that puts out 800 lumens with the light color of 5000K because I assume it has more of the red wave length than the 6500K and it will not look so blue to the eye. I have a solarium and only need supplemental light for 2 windows in my home on timers for the winter months for orchid seedlings and cuttings of other plants that I want to keep warmer. But now I'm still going to check out the 6500K 60w and also the 100 w equivalents for their lumens. Thanks again!

[Bill U.]

Not a problem! As a quick side note about color- I have found that around 6500K you really don't get much of a "blue" hue that many talk about. To me it is a very bright white light that I would liken to regular office fluorescent lighting- more white than blue-ish, which is the point of the 6500K spectra= to have both the red and blue for total growth.

That being said, some people do like more yellow/"red" light in their home, so the 5000K may not come across as glaring as the 6500K might.

Good luck and happy growing!

[kwarren]

Thanks again for your advice! Now I'm seriously considering going back to Walmart this evening and trading the 5000K daylight bulbs I bought several days ago for the 6500K. I know they have 60w equivalent and 100w. I kept my receipt and original box. I'm afraid 100w will be too strong as I can only clamp the fixture about 18" from the top of the small plants and besides, they get direct sun for about 3 hours a day anyway. I think I will stay with 60w but switch to the 6500K as long as the light is just a bright white color and is not emitting a distinctive blue cast. I think the 6500K has higher lumens also but my memory is not so good and I may be thinking of the 100w type. Thank you so much for your added imput.

[RandomGemini]

That should be good actually. A lot of growers grow their high light plants within an inch or two of those bulbs, so lower light orchids at 18" away should work out pretty well. That's about the distance I have my phals from my CFL light. I have my higher light orchids a bit closer to it than that.

[kwarren]

Thank you also for sharing your experience with these new cfl bulbs. I'm a new member with the Oklahoma City Orchid Society and have not asked other members about these bulbs and if they use them. Our Nov. meeting isn't until the 3rd Sunday and I'm wanting to make my decision and setup this type of supplemental lighting. The Orchid Board is really a lifesaver for many of us and I am always excited and very grateful for your helpful responses.

[ALToronto]

100 W equivalent is not too strong. I have 3 of them, about 24" above the plants, and they're a good supplementary light source in the winter months. I wouldn't want to use them as the sole source of light, or else I'd have to triple their number (and wind up burning the plants - they do get hot)

I've just found some LED lamps that go into a regular lightbulb socket. These are also available in big box stores, and come in warm white (2700 K), bright white (3000 K) and daylight (5000 K) temperatures. I bought some 60 W equivalents in daylight. They put out 800 lumens and are actually a little bit brighter than the 100 W equivalent CFLs (as measured with my smartphone app, for all it's worth). More expensive but a lot cooler (temperature, that is). The only problem is, most are made to be dimmable, so you're paying an extra $10-15 for a feature you'll never use. Try to find some that aren't dimmable, and you'll end up with a brighter light as well.

[kwarren]

And I appreciate your imput also, AL Toronto. I just read it after returning home from Lowes Home Improvement Center. Walmart did not have 100w cfl daylight with 6500k lighting but I found it at Lowes. I just finished putting it in the fixture and I am very happy with it. You are right that it is not too strong or too bright. And I agree very much with Bill U. that there is not a noticeable blue cast but is actually a very pleasing bright white. I am very pleased how today turned out thanks to all you guys!