T5s, grow light recommendations

MVcowboy

Active Member
Hello, I have 4 T5s that are around 17 inches above my plants. What do you guys think is the best heigh for that? Also its about 48 inches long, how many plants do you think I could have growing comfortably below that?
 
T5s need to be as close to your canopy as possible, preferably six inches / 15 cm or less.

The number of plants is dependent upon how long you intend to let them veg. You can have one plant that vegs for a long time, up to four or more that are in veg for a short time.

Although you can grow under T5s, this is not a viable long term solution. The tubes need to be replaced almost on an annual basis, as they degrade 20% per year. Replacement tubes will become harder to acquire as time marches on. Manufacturers are going to stop producing them due to environmental concerns, and the advent of LED solutions. A good LED fixture such as Mars-Hydro's SP or TS series will cost less than T5s producing the same amount of light. You will also see a reduction in your power bill, as LEDs produce much more power per watt than T5s.
 
@Old Salt is right about the need to replace florescent bulbs in a T5 fixture after about a year. The white light bulbs will look OK but they have lost some of their oomph. If the bulb is one of the florescent bulbs intended for blooming it will be very noticeable that it has lost some of its strength.

@MVcowboy, one suggestion I have is that you check to see if your T5 fixtures are HO (High Output). If they are then they seem to be compatable with either florescent bulbs, LED tubes or even a mix. All of my T5 fixtures are HO compatible.

This is all based on 20 months of active growing in a room in the basement. A T5 LED bulb seems to have several years worth of life before a drop in brightness or light level based on what I have read. For my vegetating area I ended up replacing all the lights in that area, both some LED pods and CFL bulbs (the curly ones), with two tube T5 "4 foot" fixtures and bought the LED tubes for those instead of the florescent bulbs. I like the better light coverage and the plants seem to grow better. This set-up produces less heat than the pods did.

My flowering cabinet has had "2 foot" T5 fixtures in it from day one because of shape and size. When I started buying those fixtures I bought them one at a time. I was able to play around with both florescent bulbs and LED tubes. The loss of light in the florescent bulbs is noticeable after about 10 months to a year, especially the ones that are supposed to be producing more red for flowering. After a few months I had several fixtures in the cabinet I was able to put some clones under LED tubes and some under florescent bulbs. Plants under the LED tubes grew better, with larger buds. I have a few of the florescent bulbs left in the fixtures but am replacing them with LED tubes every time I find a couple extra dollars in my pocket. I am almost done and have a mixture of white (veg) LED tubes and the tubes meant for flowering stage.

Several months ago I was curious about the T5s continued availability or if they were being phased out. So far I have come across info that it is the old florescent T12s, both bulb and fixtures, that seem to be gone. The florescent T8 fixtures are still around and for sale as far as I can see with some styles of T8 bulbs no longer available. Otherwise T8 bulbs are on the market at many lighting stores or in the lighting departments of some big box stores but it has been awhile since I looked at the shelves. The low popularity of T8s seems to be the main reason for phasing them out.

The T5 fixture and bulb are in a different category. I have not found any online articles that say the T5 is being eliminated in the US because of a govt mandate or for any other reason. The stores are selling fixtures and many different styles of bulb. I have seen a few new designs of T5 fixtures show up in the last few months in two of the 3 grow shops I visit.

I figure that by the time the HO T5 is phased out the replacements will be way above anything that is on the market now. Until I find something better for my needs they are what I am sticking with.

Have a great day.
 
Hello MVcowboy,
I do a lot of my veg under T5 HO lighting. Also I pop all of my seeds under it and root my clones under it. I really like T5 lighting. It also gives off a bit of UV which is great. Node spacing is nice and tight as well. I like Sunblaster T5's personally.
I use four 48" fixtures with the Nanotech reflectors added on. Under this 4 bulb fixture I veg four plants quite comfortably. I finish their veg for another two weeks under CMH once they move into the tent before switching to flower.
17 inches above your canopy is a bit too high. I usually stay within 4-6 inches.
No complaints.
 
Hello MVcowboy,
I do a lot of my veg under T5 HO lighting. Also I pop all of my seeds under it and root my clones under it. I really like T5 lighting. It also gives off a bit of UV which is great. Node spacing is nice and tight as well. I like Sunblaster T5's personally.
I use four 48" fixtures with the Nanotech reflectors added on. Under this 4 bulb fixture I veg four plants quite comfortably. I finish their veg for another two weeks under CMH once they move into the tent before switching to flower.
17 inches above your canopy is a bit too high. I usually stay within 4-6 inches.
No complaints.
I think T5's will be round a while for growers that don't need high illuminance and aquarium enthusiasts etc.
 
Hello MVcowboy,
I do a lot of my veg under T5 HO lighting. Also I pop all of my seeds under it and root my clones under it. I really like T5 lighting. It also gives off a bit of UV which is great. Node spacing is nice and tight as well. I like Sunblaster T5's personally.
I use four 48" fixtures with the Nanotech reflectors added on. Under this 4 bulb fixture I veg four plants quite comfortably. I finish their veg for another two weeks under CMH once they move into the tent before switching to flower.
17 inches above your canopy is a bit too high. I usually stay within 4-6 inches.
No complaints.

I bought my T5s from Lee Valley Tools. They were the Sunblasters with the Nanotech reflectors. They have stopped selling the fixtures, although they appear to still be used in their plant stands. I had to really look around for replacement tubes. I did find them in Halifax at a specialty lighting store. If I wanted something other than what they had in stock, I would have needed to buy in bulk. I forget exactly how many, but it was more than I would use in my lifetime.

Except for a mini greenhouse (plant tray, dome, light) our go-to gardening center (Halifax Seed) no longer carries any florescent lighting.

Home Depot only carries one or two types of T5HO bulbs in each size.

The Sunblaster 48" T5HO lights only put out 5022 Lumens when new. They consume 54 watts. Their luminous efficiency is 93L/W, or about half that of the LEDs on the market today. The five year cost of ownership for the T5HOs is more than double that of LED lighting.

I have one of the 16 fixtures that I originally bought left. I use it in the tent with my 'blurple,' to take pictures of my plants for posting here.
 
I bought my T5s from Lee Valley Tools. They were the Sunblasters with the Nanotech reflectors. They have stopped selling the fixtures, although they appear to still be used in their plant stands. I had to really look around for replacement tubes. I did find them in Halifax at a specialty lighting store. If I wanted something other than what they had in stock, I would have needed to buy in bulk. I forget exactly how many, but it was more than I would use in my lifetime.

Except for a mini greenhouse (plant tray, dome, light) our go-to gardening center (Halifax Seed) no longer carries any florescent lighting.

Home Depot only carries one or two types of T5HO bulbs in each size.

The Sunblaster 48" T5HO lights only put out 5022 Lumens when new. They consume 54 watts. Their luminous efficiency is 93L/W, or about half that of the LEDs on the market today. The five year cost of ownership for the T5HOs is more than double that of LED lighting.

I have one of the 16 fixtures that I originally bought left. I use it in the tent with my 'blurple,' to take pictures of my plants for posting here.
That's flat out and only people like the flashlight modders run LEDs to maximum. AFAIK LED growlight emitters are deliberately under-powered to extend their life, so they use more emitters to increase luminance.
 
That's flat out and only people like the flashlight modders run LEDs to maximum. AFAIK LED growlight emitters are deliberately under-powered to extend their life, so they use more emitters to increase luminance.

The six COBs in my fixture are rated at 300W each. The fixture draws 315W at full intensity, so yes the COBs are running at less than they are capable of. There are several reasons for this:
  • The efficiacy of the COBs, or lumens/watt is greater at lower intensities;
  • At 1800W the heat generated by the fixture would be more than six times what it is, requiring special heatsinks, and external cooling; and
  • Running at a lower power level reduces the heat at the COB's substrate, extending their life.
Heat is one of the biggest killers of solid state devices. Using devices at less than their rated power is cheaper than adding in the heat sinks required, and allows for longer warranty periods. Have a look at the specifications of the COBs put out by any of the major manufacturers, and you can confirm the more light per watt at reduced power levels claim I made above. You'll also find that even the poorest modern LED or COB produces at least 40% more light per watt than T5HOs. The better ones are producing more than twice the light per watt.
 
So the led bulbs require removing the ballast or rewiring right?
The way I understand it is if the fixture is HO then it will accept either the florescent or the LEDs. If it is not a HO fixture then some rewiring or a different ballast might be necessary.

I am pretty sure there is some explanation of how to figure it out in the lighting section or forum on this message board.
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@Greenlizard @Old Salt
Just looked and I do have the t5HO. I really have to do more research on all of lighting. There is a label on the grow light that says that it can only handle a 15A max branch circuit. Do you think that would be okay with certain LED bulbs? Also thanks! C1D6B0DC-EB14-4B30-BE88-A1EACCD6A33B.jpegE0748E9D-1E8F-4406-B987-C2DB06FD5A95.jpeg
 
The 4' T5HO lights draw close enough to 1/2A each. That means you can daisy chain up to 15 of them together, before reaching the limit. Check your LED strips to ensure they don't exceed this value.

The formula to get the current is P/E or power divided by the voltage. They don't want you to exceed 7.5A due to the inrush current when you turn them on.
 
I also use T5 HO along with 400W HPS/MH and some FAR-RED LEDs total just over 600w
they are also set on a SUN-RISE / SUN-SET Schedule so they come on and go off in stages

first photo all off
second photo only the T5s are on waiting for the HPS to start

Since I run red and blue spectrums at (VEG/FLOWER) i have to change the
full spectrum UVA/UVB Annually but the Red & Blues are every 2 years (only run half grow)

I originally was using Only a 600w hps but found I can get better lower growth with the
200w of T5 Side lighting




It looks like a stage ready for a light show! Who's playing?
 
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