Just look at the kelvin rating of the bulbs to determine color temerature emitted. If it is around 5000 then it is a full spectrum bulb (the sun is around 5000k). Depending on what you are growing higher and lower k bulbs can be beneficial, but this can usually be accomplished in a dual bulb fixture with one lower and one higher k bulb.

You will also do well to compare the lumen output of each bulb with other bulbs of the same color temp. If one puts out more lumens for the same price then all other things being equal prefer the higher lumen output.

The high priced bulbs are not, in my opinion, worth the money. They usually are very good bulbs, but the difference in plant performance is almost always minimal and the price is exponentially different.

Nope, not true. Colour temperature and "full spectrum" are completely unrelated. Colour temperature is a measure of the overall colour of the bulb. Full spectrum is a piece of marketing hype that is applied to almost any bulb that emits more than two spectral lines :)

Daylight bulbs are often 6500K, sometimes 5000K. Both will appear as a bluish white compared to other light bulbs. The cool white bulbs are 4100K and will appear as a fairly clear white. Cheap cool white or daylight fluorescents have a very poor colour rendition index (CRI less than 80) and make the room look very stark or grey. This might not be good for your needs.

There are several ways to avoid the stark grey look. One is to buy a warm white bulb. The CRI might still be very low, but everything will have a cosier tint. This is probably not the best approach for a plant light but is a nice light for a bedroom. Or you can buy a high CRI bulb which shows colours more accurately. Look for CRI above 80. "Full spectrum daylight" bulbs often have a CRI above 90, but they are expensive. Do check the CRI because "daylight" and "full spectrum" mean nothing. The other approach is to use the pinky-purply gro-lux bulbs. They are also expensive and they aren't to everyone's taste, but if you like the appearance then that's fine.

If you could provide a link to the exact product you are considering we could offer an opinion. Normally I would say that a high CRI bulb is unnecessary, but when they are the only light it may be important just to make the plants and flowers look nice.

One last thought on economy. Using ten 24" tubes is quite inefficient. The bulbs cost about as much as a 48" tube that will put out more than twice as much light, plus the 48" tubes are generally more efficient and easier to find. Replacing the fittings would quickly pay for itself in electricity savings and fewer new bulbs.

Nope, not true. Colour temperature and "full spectrum" are completely unrelated. Colour temperature is a measure of the overall colour of the bulb. Full spectrum is a piece of marketing hype that is applied to almost any bulb that emits more than two spectral lines :)

I stand corrected.

Hi,

I would like to thank both of you for responding to my question. The address of the page that I'm looking at on the web site is: http://www.1000bulbs.com/category.php?category=1471 I will put a link to it on the bottom of this thread entry.

Yes, it would be much more efficient to have 48 in. bulbs but my plant shelves only accommodate 2 ft. fixtures. The space constraints in my small house would not allow me to have 4 ft. plant stands so I had to go the 2 ft. route.

The daylight bulbs that I'm looking at has a CRI of 79 which is about what you said would be a minimum for an aesthetically pleasing light. The attractive thing about this company is that each light bulb is around the $2.50 range. We are slowly sliding into retirement and I'm willing to sacrifice a little bit in order to get something that will fit in our new budget. Because of the 30 bulb minimum I would really like to have the same two bulbs in each fixture so that I don't have to buy two boxes of 30 bulb's each. Of course, before I would buy a whole box of light bulbs I would try to find just two of the bulbs that I'm interested in and check them out first to see if they are something I could live with.

So, let me know what you think. If you know of another place to buy light bulbs that are reasonably priced I would be interested to look into it too.

Thanks again,

Larry

Here is a link that might be useful: Light Bulbs

I don't think you have to buy a case there. I tried to put a single bulb into my shopping cart and it let me. There is a $35.00 minimum order, but that appears to be all so you may not have to commit as much as you thought.

do you have a large hardware store near you? I generally find that for general purpose bulbs (rather than 'grow bulbs' the hardware store is a good place ( so are big box stores like Wal-Mrt). You might pay a little more per bulb, but you don't have to buy a case at a time either.

What you are looking at is just a plain jane tube (which is just fine) and nearly everywhere that sells floro tubes is going to have something comparable.

may i just jump in here and ask a question?
this is my first plant stand/lights.....4'
i simply need to know what bulbs to put in?
i am starting roses and jap red maple seeds....my stand is 18" deep....2..4' lights on each shelf...is this sufficient? i was told that the brighter the lights the better for the seeds and plants?
thanks

Before I switched over to CFL bulbs, I used 48" T12s. FOr that plant stand, I used a combination of Philips daylight deluxe and Philips cool white bulbs. It worked great, and the plants didn't complain much.

I will say, however, that unless your plants will be so close to the light so as to be wearing the lights, they might not get enough light.

I just started growing african violets under fluorescent lights and I am a little confused. I have a four shelf stand with two - two foot bulbs above each stand. They are the Sylvania Growlux 20 watt - wide spectrum bulbs. I am wondering if those are the correct lights for growing african violets; On the bulb box it says for direct sun flowering plants. So far, the leaves on my plants look fine but the flowers seem to be dying. Also, I was wondering how far away do you usually keep standard size african violets from the bulbs? The tops of my plants are about nine inches away from the bulbs. I have read several books but they have conflicting advice.

Thanks!

ZuzuIL,

I currently have a simular setup as you have for my African violet and other geseriads. Although, I even have my African violets a little closer to a light than you do. This is basically not my choice but due to the fact that my shelves are not adjustable. I have had this setup for years and my African violets do just fine.

The reason I started this thread is because the growlux bulb combination I have is so expensive. I am looking for an alternative that is much cheaper. I'm fairly convinced that having two daylight fluorescent bulbs will do the trick. I am going to try to find a place where I can find them individually to give it a try. I will be very surprised if they don't work though.

I hope this helps,

Larry

With African Violets, the flowers dying could be anything from humidity to food. I wouldn't suspect that you have the "wrong" light, necessarily. I'm pretty sure that from any commercially available lights, you won't get a light that will harm your plants.

THey may not prosper, but it certainly won't harm them.

Do you think water in trays under african violets would provide enough humidity?

Thanks for any advice.

ZuzuIL,

Water in the tray should be enough, but understand that growing African violets is more of a religion than a science. They are incredibly finicky plants that nobody really knows how to grow well.

I think African violets are one of those plants that people who love to baby things are attracted to and their enthusiasts love to come up with complex routines and raindances to get them to stay healthy and bloom. It usually doesn't work and they die after a long period of slow decline and no blooming.

Sorry, I just hate African violets.

Hey ZuzuIL,

Don't let username_5 (shame on you. lol) discourage you. African violets are not as difficult as some would say they are especially if you grow them under lights. I see that you have a few entries over on the African violet forum. That is probably the best place for you to ask these kinds of questions.

As far as the trays of water are concerned, it is okay to do that as long as the violets don't sit in water. That means putting rocks or upside down saucers or anything else inside the trays to keep the pots from touching the water.

As far as your blooms dying, how long do your blooms last? How long ago did you buy your African violets? And I'm curious to how many violets you have.

Larry

what light bulbs are right for growing a little of everything...seeds to plants...cuttings of roses etc.?
indoors under light...baggie method tried but doesnt suit me! most things rotted away!..i can use 2 florescent lights per 4' shelf...or even 3 if necessary?
just tell me what most people use....
suzanne

I know this was originally a light string - but I would like to add that I grow my African violets without lights - East-facing and South-with over hang windows and they flower on and off all year.

For the people asking about general purpose seed starting and cuttings, get yourself some cool whites. These will need to be very close to the seeds for typical summer annual plants that would otherwise be growing with direct sunlight.

For African Violets, they aren't impossible to grow, but they do prefer a fairly narrow range of bright indirect light, moderate soil moisture, and suitable humidity conditions. I just grow them on a window-sill but I have the advantage of decent humidity all year and rarely get excessive heat or cold.