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What does all this information mean?

Posted by jennieboyer 8 (My Page) on
Fri, Dec 28, 12 at 9:15

I've been researching grow lights online, and I'm very confused. I am finding wattage, K, and lumen information, along with the red, green, blue spectrums. What is the important information? For example, if a light is 6500 K and 2000 lumen, is that good for starting vegetable seedlings? How does wattage play in? Sorry for the newbie questions, but very, very confused! These lights are so expensive, and I'll be doing several dozen seedlings, so don't want to mess it up on purchasing. Also, any recommended place to purchase? Thanks!


Follow-Up Postings:

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RE: What does all this information mean?

to start vegetable seedlings, u just need a cheap shoplight from walmart that runs T8 lamps, and use a pair of cool white lamp. keep the lamps within 1-2" of the top of the seedling, and u will be fine. 6500k means the blue is way more than red, and is not necessary. 4100K (cool white) means the red and blue are balanced, and this works perfect. 5000K is also higher in blue than red, and that is also an excellent choice. 3000K is very red and is generally only used for specific reasons, and not usually for seedlings. Lumen is the total amount of light photons being produced per second, and lets u compare different lamps. for instance, in T8, some lamps will give 3200 lumens (very good), or just 2700 lumens (mediocre). the shoplights will come with chains, so u can hang them from the ceiling, and keep ur trays on a table, very close to the lamps. if u make a little stand out of some 2x4 lumber, u can support the fixtures with the stand, and have a shelf to put your seedling trays.
u may need to be a little bit inventive - it might help if u have a friend that has a saw, as well.


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RE: What does all this information mean?

Thank for reply "overdirve". Your tips can be helpful for vegetative seedling. Thank for your ideas.


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RE: What does all this information mean?

Overdrive pretty much nailed it.

You can use wattage to determine what the impact on your electric bill will be. Find your cost per watt from your bill and do the math. Fluorescent lights are by far the cheapest with T5 having an efficiency advantage over T8's. There are more expensive though...so do the math upfront.

Find the shoplights on sale at menards, home depot, lowes etc. It pays to wait a week or tow as they seem to come on and off sale in that time period.

Best of success!! Starting your veggie garden indoors is a serious efficiency multiplier!! Especially for peppers and long duration tomatoes.

Here is a link that might be useful: My Indoor Growing Adventure


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RE: What does all this information mean?

  • Posted by dsws none (My Page) on
    Fri, Jan 25, 13 at 18:35

Lumens aren't quite the total number of photons emitted per second, although that's a good enough description for practical purposes. To get the number of lumens, you add up the number of photons per second at different wavelengths, weighted according to a standard curve that's supposed to represent how useful the colors are for helping people see. That's not the same curve as how useful the colors are for helping plants grow.

But plants do use the whole spectrum that we can see by, even if the efficiency isn't quite the same. (Our eyes are best at seeing yellow and green, whereas plants are more efficient at using red and blue.) So comparing lumens to lumens, or lumens per watt to lumens per watt, is good enough for most purposes.


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