Lights Ordered: What Config? 8 x 4 Foot Bulbs. Help?

[CrossOps]

Guys, I have lights on the way, its 8 bulbs that are four feet each.

Lumens: 40,000 total
Lights: T5HO (6500k)
Wattage: 540 total watts

I am able to substitute some 3000k bulbs in place of some of the 6500k bulbs. Should I do this, and what ratio? This is for tomatoes, peppers, cukes, etc.

Essentially, I can either put in 6500k or 3000k bulbs, 8 positions. Want feedback before I confirm the order.

[GpsFrontier]

Here is a link that explains the florescent light spectrum's: Color and Mood : ENERGY STAR

P.S.
I don't know what your paying for the T5's to order them, but here I can get them at Home Depot and Lowe's. I forget which has the ones I was looking at, but a twin 4 foot long T5 light fixture sells for about $35, and that includes the bulbs. But they have 2 and 3 foot fixtures as well. Also Wal-mart usually has even cheaper prices if you can find the fixtures you want. I was looking for twin 4 foot T8 fixtures and found them at Wal-mart for $10, I'm sure you could find T5 there too.

[CrossOps]

Thank you GPS. I received them at a price I couldn't really pass up. My question is, how many of those 8 should be 6500k, and how many of those 8 should be 3000k?

[GpsFrontier]

That's why I posted the link, so you could decide. I could easily say 50/50%, but there are too many variables to consider. Some are I have no idea how many plants you plan on growing, how far away the foliage will wind up being, how you plan to distribute the light etc.. From your post you plan to grow 3 large type plants (tomatoes, peppers, cukes). That would have me concerned with the minimal lighting (4 twin fixtures) you posted that you plan to use (even growing only one of each plant). That may do fine while the plants are young, but good luck growing those large (light incentive) plants to maturity without more light.

Bottom line, the amount of "light intensity" is much more important than the spectrum (especially with florescent lights, as well as the plants you mentioned growing). Typically blue spectrum (natural daylight spectrum 5000-6500k) focuses on foliage, and red/orange spectrum's (warm white, 2700-3000k) focus on flowering for florescent lights. But that isn't always the case, or even important with florescent lighting. The light intensity (how much light you provide) is much more important. Especially for plants like tomato's, cukes, and peppers that require much more light to do photosynthesis than non fruiting plants, and those plants don't rely on the spectrum of light to trigger fruiting. Their continuously fruiting plants. Witch means they grow fruit all season long (regardless of the suns light spectrum during the season).

If it were me, I would probably use all 6500k lights, unless I was sure I had enough light intensity (all around the plants) to grow the plants to full size. Then I might use 50% 6500k, and 50% 3000k for continuously fruiting plants like peppers, tomato's and cucumbers.

[CrossOps]

Originally Posted by GpsFrontier

If it were me, I would probably use all 6500k lights, unless I was sure I had enough light intensity (all around the plants) to grow the plants to full size. Then I might use 50% 6500k, and 50% 3000k for continuously fruiting plants like peppers, tomato's and cucumbers.

Thank you GPS. The lights did not cost me anything (swapping for sidework that take me an hour at most), so I went ahead and put the second request in for two sets of these based upon what you stated. Your a wealth of information GPS, many thanks. I tend to like to ready and study what others do, and then learn from it as I set it up.

The twin setup would essentially put me at 80,000 lumens, or 800 watts to start. I suspect that would be sufficient.

[GpsFrontier]

When you say 8 bulbs, I don't know if that's 8 light fixtures with one bulb each, or 4 twin bulb fixtures (two bulbs each). Also you mention 540 watts, as well as 800 watts. 540 divided by 8 comes out to about 68 watts each. That seems like a lot of wattage for one 4 foot bulb. The T8's light's I plan to get are 32 watts per bulb (64 total watts for a twin light fixture), but I never checked the wattage of the T5's and I guess it's possible their twice the wattage of the T8's.

But any witch way I simply cant say if 540-800 total wattage of florescent light is enough for your planed setup. It not just the wattage, it's how evenly you can distribute the light around the plants. As well as not allowing the light source (bulbs/fixtures) to be to far away from the plants foliage (hopefully no more than 18 inches away). The more light sources you use, the more evenly you can distribute the light around the plant/s. But the florescent lights still should be close to the plants foliage or the useful lumens will drop significantly, thus not do the plant much good (wasting your wattage/lumens). So your light array/configuration is extremely important to how well the florescent lighting will do for you.

To compound the issue of florescent lighting, you plan to grow three types of large bushy plants that continuously produce fruit. Even if you only planed to grow one of each, they get large and bushy (unless you trim the heck out of them). That makes it more difficult to evenly distribute the light to all the foliage. Even if the plant has a lot of nice looking leaves, only the leaves that are getting sufficient lighting will be able to do photosynthesis. It's just like having a lot of solar panels on the roof, the ones in the shade wont be doing much good. You would want to put them all in a place they get enough light or they wont be doing much good.

Usually I would say if you will be using 800 watts of electricity anyway, you would be better off using 2-400 watt, or 4-200 watt (for better light distribution) HID lights. But I can certainly understand if you are getting the lights for practically free. I wouldn't pass that up either (no mater what). Heck, with that many florescent lights, you'd be able to grow enough lettuce for everybody on your block.