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Give me clarity or give me death!

Posted by GardenBoo z9 SF Bay Area (My Page) on
Fri, Feb 18, 05 at 18:37

Okay, I read a whole bunch of stuff on the forum about picking the right lights and tubes for seedlings and I'm more confused than ever! It looks like I will have to put some major time into untangling the mess I've created in my head. But for now, since I want to get started this weekend, I'm in desparate need of some REALLY, REALLY, dumbed-down basic advice.
I just need enough light for tomatoes and pepper seedlings on a single 4ft shelf. I'll hang it from the ceiling with chains.

1 fixture or 2?
I'd rather not do any overdriving, turbo charging or souping up, etc., unless I really need to (I'd probably burn the garage down).
Reflectors or not?
Shoplight or something more expensive? Examples (brand and model name or #)
T8 or T12 bulbs?
Mixture of cool and warm (whatever that means) or a Philips Deluxe or what?

Sorry, I really am interested in wavelengths, lumens, light meters and all that stuff, but right now I just need some really quick help. Gotta go. Thanks

Follow-Up Postings:

RE: Give me clarity or give me death!


I'm just a woman with a few hundred germinated seeds and I have a 4 tier mini-greenhouse that has cheap Walmart grow lights (7.59) in it.

I realize that there are lots of bigger, better, more and totally over my head lights and methods but if you want simple this is what I have.


RE: Give me clarity or give me death!

That's an interesting setup. Where did you get the cart? And the plastic cover? Is it 36" or 32" wide? Also, why are all the plants sitting on inverted pots? To get them away from the heat of the lamps?
Maybe I should do something like that. Can't believe the Walmart lights were only $7.59! Replacement bulbs must be pretty cheap, too?

RE: Give me clarity or give me death!

<<1 fixture or 2?>>
Depends how wide your shelf is. If it's one foot wide or less, one fixture. If it's two feet wide, two fixtures. In between, either is OK but more is always better. If you can put your shelf next to a window for added light, even better!
Buy cheap shop lights. You're only going to need them for a few months per year. You can buy ones that have reflectors.

T8 is a bit more efficient and contains less hazardous waste to pollute the environment when it's time to throw away the bulbs. T8 can use an electronic ballast, which doesn't make that humming noise - annoying in a living area, doesn't matter much if you're growing in the basement or garage or a place where noise won't bother you. T8 fixtures and bulbs will likely cost a bit more than T12, but not always.

To start seeds, it doesn't matter. Go cheap. Cool white will probably be cheapest. A mix of half cool and half warm white resembles daylight and is nicer to live with. (If you might use the bulbs later for flowering houseplants, you'll want the mixture.)

<> A four foot shop light uses four foot bulbs, which are 40 watts. T8 bulbs actually are 32 watts but put out approximately the same amount of light.

Hope that helps! Good luck!

RE: Give me clarity or give me death!

The plants in Cindys setup are elevated to get them closer to the lights. It looks like the lights are fastened to the shelves, not hanging on chains, and if you cant lower the lights, you have to elevate the plants.
You can rig a setup similar to Cindys with shelving units and shop lights from Sams Club, Lowes, Home Depot, etc. I dont think you need the plastic cover unless the unit is outdoors and frost threatens.
Its nice little greenhouse.

RE: Give me clarity or give me death!


I bought the mini-greenhouse at Lowe's for $50.00 but FarmTek has the same thing on sale for $27.95.

I have the lights wired to the bottom of the shelf above and prop up the seedlings with whatever is handy to get them close to the light. It's something I learned to do on this forum and it is making a big difference.

I don't know if the cover is necessary but it seems to work well in my case. Mine is set up is in my heated sunroom. I think it is about 30" wide and about 18" deep. I like that it doesn't take up much floor space but I can get a lot of stuff in there.

RE: Give me clarity or give me death!

Cindy, I got the same mini greenhouse as a christmas prsent, or one very similar. I have it outdoors, a bit like a cold frame, its keeping my pot ghetto tidy. Maybe I'll use it for cacti in the summer. No lights.

Jerry, I'd go with two bulbs or four, however many you can fit into the width of the seed trays you want under there. You are unlikely to ever have too much light for tomatoes and peppers, especially when the tomatoes get to be a foot high! A warm bulb has a reddish light and a cool bulb has a more bluish light. You'd never notice most of the time, but put them next to eachother and you'll see the difference. There are lots of tubes with deluxe in the name and they are generally good for plants. Use just cool white deluxe or daylight deluxe tubes if they are a sensible price, otherwise use a mix of cool white and warm white.

T8 bulbs are often a bit more efficient than T12, but you might have trouble getting them in 48" lengths and higher powers. Longer tubes are more efficient. You should be looking for 48" 40W bulbs. You can get more powerful bulbs, but they tend to be specialty items and can cost a lot more. Four 40W bulbs will nicely light a 4'x2' area for your seedlings.

RE: Give me clarity or give me death!


Simple Answer:

If you don't plan on overdriving them you may want to use two fixtures. (depends on how wide the shelf is)

You can't burn down your house by Overdriving. Either it will light up or it won't.

Reflectors, YES!!!

Shoplight. Best Bet would be Commercial Electric at Home Depot for $7.94 I believe it is the red box....mmmm....maybe the grey one.

Use T8 bulbs cool white; 3.95 for a two pack.

All 4ft T8's are 32WATTS

I believe this is all you need.

Lightmaster -j- "Jerry"

RE: Give me clarity or give me death!


All of the above is good advice. However, in case you are still confused with all the talk about warm vs. cool lights which was also very confusing to me when I set out to find some lights, as you want find the word warm written on any of the light bulb packages.

However after much study and inquiry, I went to Home Depot bought the cheap shop lights for 7 or 8 dollars with electronic ballast written on the box. Make sure it says electronic ballast or it will not work as well over time.

As for the 48" bulbs to put in the shop light, I look for a number followed by the letter K which will be listed somewhere on the lightbulb package, 4100k, 5000k, 5600k etc. somebody correct me if I am wrong but it is my understanding that any bulb with a number written on the box over 4100k will grow tomato and pepper plants big enough to set them outside..

If the lights do not have a 4100k or higher number written on the box, I keep looking until I find one that does.
hope this helps,

RE: Give me clarity or give me death!

I'm not sure that cheap electronic ballasts last over time any better than the older style magnetic ones. I've killed off several electronic ones in a matter of months, but some have lasted for years. Of course, I do tend to dribble water around a lot...

RE: Give me clarity or give me death!

--I'm not sure that cheap electronic ballasts last over time any better than the older style magnetic ones. I've killed off several electronic ones in a matter of months, but some have lasted for years. Of course, I do tend to dribble water around a lot...--

Are you using fixtures like Lights of America, or any that have ballasts on each end? If so, you wasted your money!


RE: Give me clarity or give me death!

I was confused and in a hurry, too, as my seedlings were coming up and we are having a dark, cold spring --- I found the FAQ at the starting from seed forum to be very helpful regarding lights. Maybe the administrator could link to that or ask to use it over here.
Just got back from Lowe's with all the stuff to make my grow lights. Thanks for all the advice, folks, and I'll be back for more, I'm sure.

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