grow light lumens
My Tomatoes always get spindly under my cool lights, Is a warm light, or mixture better?
So far the last 3 years I have grown tomatoes and other various things from seed indoors about 8 weeks prior to the last frost date. And every year my tomatoes get VERY tall and spindly while growing under a dual 4' bulbed (cool 4100k) flouresent shop light. I had purchased the fixture and lights new, and they only have 6 months of usage so far, I know they lose lumens after awhile.
I keep the lights as close as possible, about 1" at all times above the plants, and can move the light up/down when needed. I usualy run the lights about 12 hours a day or slightly more. I also have a small fan I run when the lights are on.
But every year they get very tall and spindly, they dont have those nice thick stems like in the nursery's.
So, should I use one warm light and one cool? Or what else could be causing this?
The average temp in the room is 70-75 all the time. Would a cooler night help as well?
Thanks for the help!
Plants need a balance of red and blue light to germinate, grow, bloom and bear fruit. But I don't think that's your problem. And you're not alone.
Down in Florida, where tomato growing is serious money business, too many cloudy days are one of those "acts of God" that can cost growers a bundle, most often in December and January when days in The Sunshine State are often overcast.
Mid-day full sun exposure can pour 10,000 footcandles onto unshaded leaves. But growers know they can aim for 3,500 footcandles and still make a profit. So they lower the barre for those 2 months.
"In Florida these low light periods are usually short in duration so that lighting is not needed. It is a good idea to place white, reflective plastic on the floor of the greenhouse to reflect light back to the tomato plant canopy."
You, however, are light-years from reaching that 3,500 footcandle minimum with the setup you have. Two 4 foot fluorescent tubes? How many footcandles do you squeeze out of those? One estimate comes from an American Orchid Society orchid-lover, who tested a mere 250 to 450 footcandles of light on plant leaves from a single 4' tube:
www.aos.org/AM/Template.cfm?Section=Orchid_Resources1&CONTENTID=6616&TEMPLATE=/CM/ContentDisplay.cfm
Then there's the matter of sunlight. In areas with a long growing season, cloudless spring skies pour solar radiation all over tomato leaves and fruit.
This has the effect of increasing the number of tomatoes a vine will produce. It's also credited with stirring up sugar production. In some greenhouse farms, you'll pick sweetest tomatoes in the springtime when there are the fewest clouds. One theory holds that solar rays heat the fruit, boosting enzymes that control sugar production.
It’s clear that long, bright, sunny days rev-up flavor. It’s just that no one just yet knows exactly how this works.
Which brings us to the matter of temperature.
Very cool air -- the kind you get in a refrigerator, or on a cool morning in Autumn in New York -- ruins tomato flavor. Dip much below 50 degrees F, and you may as well use that tomato at batting practice. The delicate flavor enzymes are not built to take that kind of chilly reception.
Above that, flavor improves with each degree.
http://edis.ifas.ufl.edu/cv266
Production of Greenhouse Tomatoes - Florida Greenhouse Vegetable Production Handbook, Vol 31.
L.I.G.
A look at what is currently available on eBay
 50 W Led grow Light 25X3 watt 60 degree chip 4220 Lumen US $109.00 
|
 INDUCTION 200watt Grow light/High lumen output Water proof/Dust proof US $599.00
|