GROW LIGHTS?

robertoccm · September 23, 2012

Lamp Shape T8
Base Type Medium Bi-Pin (G13)
Length 24"
Diameter 1"
Watts 17
Average Life 24,000 hr.
Lamp Tone Cool
Color Temp. 4100K
CRI 85
Start Type Rapid
Initial Lumens 1400
Mean Lumens 1280
Primary Application General Purpose
Lamp Designation F17T8

Is this useful to grow seedlings? How many inches above the seedlings must this bulbs be? How many hours should it be turned on?

ContainerTed · September 23, 2012

There's a lot of threads with discussions of different lighting for growing plants and for starting seedlings. A simple search for "Grow Lights" will yield a bunch.

I start about 300 or more tomato seedlings each year. I use T-12 fixtures with 6500K daylight bulbs. If you're only doing a few plants, then T-8 or smaller will be fine. Some folks here say they use the cooler bulbs and get great results. Some folks have used large expensive halogen and mercury vapor lights and gotten mixed results.

The lights you list above are adequate and should be kept as close to the top of the plants as possible. Most folks try to position them within an inch or so of the seedling's foliage. As the seedlings grow, either the plants or the lights need to be repositioned so that the plants don't touch the lights.

feldon30 · September 23, 2012

For starting tomato seedlings, you really shouldn't have to spend more than $35 for a 4' fixture and 2 bulbs. I'd look at Home Depot or Lowe's. The Walmart fixture won't last.

amideutch · September 23, 2012

Those are the same tubes we have in our 4 tube ceiling fixtures at work. Depending on how many seedlings you are going to grow will determine the illuminated area and how many tubes you will need. 4100K will work fine. Ami

Hotwired · November 30, 2012

I'm a retired optical engineer, and put significant effort into evaluating various lighting systems. Plants require different light for different stages of growth. Foliage needs green and flowering and fruiting requires red. The optimum affordable color temperature for seedlings ad growing plants for outside planting is about 5500k to 6500k. http://imageshack.us/a/img18/173/temperaturee.jpg

Here's a spectral curve of 6500k CFL bulb compared to the PAR requirements of a tomato plant. http://imageshack.us/a/img560/3693/daylightcflcurve.jpg

If you are flowering or growing fruit inside, then you need to add some red or warm white Florescent light. Here's the spectral curve of a warm white CFL compared to PAR.

Some of the commercial growlights put out some heavy-duty lumens. The real problem is that most of the lumens are at a wavelength that the plant doesn't use. I bought 500w growlights before I figured out that florescent 200w Daylight Bulbs would put more usable light on the plants. http://imageshack.us/a/img695/6125/267eh.jpg

Hotwired
http://www.hotwiredgardens.com/pdfs.html

coinshooter · January 20, 2013

can you use them spring bulbs

September 23, 2012	#1
robertoccm Tomatovillian™ Join Date: Jul 2012 Location: Mexico Posts: 80	GROW LIGHTS? Lamp Shape T8 Base Type Medium Bi-Pin (G13) Length 24" Diameter 1" Watts 17 Average Life 24,000 hr. Lamp Tone Cool Color Temp. 4100K CRI 85 Start Type Rapid Initial Lumens 1400 Mean Lumens 1280 Primary Application General Purpose Lamp Designation F17T8 Is this useful to grow seedlings? How many inches above the seedlings must this bulbs be? How many hours should it be turned on?

September 23, 2012	#2
ContainerTed Tomatovillian™ Join Date: Jul 2008 Location: 6a - NE Tennessee Posts: 4,538	There's a lot of threads with discussions of different lighting for growing plants and for starting seedlings. A simple search for "Grow Lights" will yield a bunch. I start about 300 or more tomato seedlings each year. I use T-12 fixtures with 6500K daylight bulbs. If you're only doing a few plants, then T-8 or smaller will be fine. Some folks here say they use the cooler bulbs and get great results. Some folks have used large expensive halogen and mercury vapor lights and gotten mixed results. The lights you list above are adequate and should be kept as close to the top of the plants as possible. Most folks try to position them within an inch or so of the seedling's foliage. As the seedlings grow, either the plants or the lights need to be repositioned so that the plants don't touch the lights. __________________ Ted ________________________ Owner & Sole Operator Of The Muddy Bucket Farm and Tomato Ranch

September 23, 2012	#3
feldon30 Tomatovillian™ Join Date: May 2006 Location: Rock Hill, SC Posts: 5,346	For starting tomato seedlings, you really shouldn't have to spend more than $35 for a 4' fixture and 2 bulbs. I'd look at Home Depot or Lowe's. The Walmart fixture won't last. __________________ [SIZE="3"]I've relaunched my gardening website -- [B]TheUnconventionalTomato.com[/B][/SIZE] * [I][SIZE="1"]*I'm not allowed to post weblinks so you'll have to copy-paste it manually.[/SIZE][/I]

September 23, 2012	#4
amideutch Tomatovillian™ Join Date: Feb 2006 Location: Germany 49°26"N 07°36"E Posts: 5,041	Those are the same tubes we have in our 4 tube ceiling fixtures at work. Depending on how many seedlings you are going to grow will determine the illuminated area and how many tubes you will need. 4100K will work fine. Ami __________________ Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘...Holy Crap .....What a ride!'

January 20, 2013	#6
coinshooter Tomatovillian™ Join Date: Jan 2013 Location: ohio Posts: 4	grow lights can you use them spring bulbs

November 30, 2012	#5
Hotwired Tomatovillian™ Join Date: Nov 2012 Location: Ithaca, NY - USDA 5b Posts: 241	I'm a retired optical engineer, and put significant effort into evaluating various lighting systems. Plants require different light for different stages of growth. Foliage needs green and flowering and fruiting requires red. The optimum affordable color temperature for seedlings ad growing plants for outside planting is about 5500k to 6500k. http://imageshack.us/a/img18/173/temperaturee.jpg Here's a spectral curve of 6500k CFL bulb compared to the PAR requirements of a tomato plant. http://imageshack.us/a/img560/3693/daylightcflcurve.jpg If you are flowering or growing fruit inside, then you need to add some red or warm white Florescent light. Here's the spectral curve of a warm white CFL compared to PAR. Some of the commercial growlights put out some heavy-duty lumens. The real problem is that most of the lumens are at a wavelength that the plant doesn't use. I bought 500w growlights before I figured out that florescent 200w Daylight Bulbs would put more usable light on the plants. http://imageshack.us/a/img695/6125/267eh.jpg Hotwired http://www.hotwiredgardens.com/pdfs.html