t5 vs metal halide

I'm under the impression that t5 will outperform a metalhalide of similar wattage. because with a metal halide it is a single point of light, but with a t5 there are many bulbs spread across the canopy.

if you'd imagine a square with a point in the middle, the distance from the middle to the bottom, may be small, but the distance from the center point to the far left or far right is considerable. with a t5, there is much better coverage of light and hence the distance square rule, by keeping the lights closer less light is loss.

but the metal halides use reflectors, so is it a single point of light or a beam of light? what are your thoughts?

and though with t5 the bulbs may be closer, youd need more bulbs to get the same wattage as a metal halide? I think

I remember reading in one of the books it was saying the more lights you have the better.

3, 400watts are better than 2 600watts because you then have 3 points of light instead of 2, even though its the same wattage your covering the area more effectively

true?

what are some thoughts

does anyone have ideas as to why a metal halide may be better suited towards vegging? I've been convinced that t5 is the way to go. Would like to get into discussion on this.

Mh put out more lumens overall

My 600 made my girls 4 ft in 30 days

as fare as I know two 600W will put out more Lumens then 3x400W, in other words you get more light per watt used

T5HOs are great as they produce next to no heat and is fairly cheap to run, bulbs last long with very little light output lost and is also pretty cheap to replace, biggest down side is light penetration, need to be with in 2-4 inch`s to provide really strong light, up to 10" is ok but after 12" my light meter don't show much, so for Veg they are great wile the plant are smaller and don't need so much light, once in flowering they will need 3x the amount of light so even T5HO don't quite cut it IMO tho with some training /LST/Scrog you can produce some ok smoke, another good thing about running a T5HO light is that you can mix up the Kelvin/color of the bulbs

btw T5 also come`s in the VHO type = very high output



a MH will grow your plants faster and cover more ground, but also cost more to run and you need more ventilation to manages heat, safety and and stealth might also be a issue ..

After 2 grows, I find I don't like the MH time of my tent, it gets too hot even though it is dimmed to 50%

biochem1l said:

I'm under the impression that t5 will outperform a metalhalide of similar wattage. because with a metal halide it is a single point of light, but with a t5 there are many bulbs spread across the canopy.


I remember reading in one of the books it was saying the more lights you have the better.

3, 400watts are better than 2 600watts because you then have 3 points of light instead of 2, even though its the same wattage your covering the area more effectively

.

Click to expand...

ok a T5 will not out perform a m/h , there not much in it as m/h are shit , however this is for lower watts , at higher levels of wattage then any hps will become miles better than a T5 for the simple reason you get better penetration , you can get round this lack by growing in a certain style such as keeping the plants small as poss , training or a screen , on a traditional 4 foot plant a T5 will do you a massive dis-service yield wize , better being honest to use T5 for veg where they excel

3x400 better tha 2x600 ? nope , nothing at all to do with 3 points of light which is a misnomer and everything to do with the very quality of light produced , they cover the exact same footprint but the 400 will penetrate a canapy down about 18 inch while a 600 hps will go down near 3 foot , thats 3 foot of useable light and not a glimmer of illumination

T-5s make for shorter stockier plants during veg. A MH will have taller not as bushy plants. That has been my experience. I start mine under a T5HO and then after 3-5 weeks I put them under the MH. I have really seen a difference (bigger plants and more production) with this set up in my grows as compared to when I just vegged them under the T5HO.

A good quality Halide, one that puts out good blue\green (the light itself will be an intense white), will give you more compact growth and you can keep the light close if it is air-cooled. You clearly do not get the same penetration or over-all efficiency as a 600, 800 or 1000 HID lamp which will put out 95-160 lumens per watt.

moggggys said:

ok a T5 will not out perform a m/h , there not much in it as m/h are shit , however this is for lower watts , at higher levels of wattage then any hps will become miles better than a T5 for the simple reason you get better penetration , you can get round this lack by growing in a certain style such as keeping the plants small as poss , training or a screen , on a traditional 4 foot plant a T5 will do you a massive dis-service yield wize , better being honest to use T5 for veg where they excel

3x400 better tha 2x600 ? nope , nothing at all to do with 3 points of light which is a misnomer and everything to do with the very quality of light produced , they cover the exact same footprint but the 400 will penetrate a canapy down about 18 inch while a 600 hps will go down near 3 foot , thats 3 foot of useable light and not a glimmer of illumination

Click to expand...

how are you sure that they cover the same footprint?

about the point in a square (light in a box) representation below

<. . .> <. .>
============================ ============================ = base of box

as you can see by having more points there is less distance between, and less distance from the base to the light.

the further the light is, the less lumens. in the left example, we can see that there is minimal distance from the middle light to the bottom, in the right representation there is a larger amount of distance between the light and the middle of the box. This depiction kind of shows that in the left, there would be better coverage than in the right

so are t5's not as effective for vegging than the MH?

how come?

don't t5's give more coverage? (Would that depend on the size shape and angles of the reflector of the metal halide?)
and wouldnt the t5 have a better distribution of light? vs a single point? or again would that depend upon the footprint of the reflector?

can someone please explain if it is a misnomer or not?

I thought by having more lights, then youre having better coverage, vs having a large light hanging in the center of the room. wheras the t5 has a bulb going down ever inch or so of plant, so the light is projected evenly. Does this happen with metal halide when its using a reflector? A lot of light is lost when using reflectors.

is this the footprint? the area that gets the most light under a reflector? So by having more points of light wouldnt the room be getting more more even light vs 1 big light?

bump.

the distance square principle states that if i have a 6 foot room for instance, and the light is in the middle, by the time the light reaches the sides ((3foot) the light has drastically reduced. Therfore by having 3, 200 watt lights (if there was a thing) more evenly spaced, the better the footprint

Your not looking for lumens I know not why people still measure light like this, you need PAR Light, google it, I HID which is the style of light a M/H and HPS are will always out perform a Fluoro because it's Intensity is greater, you will need to cool it because it gets hot because it is so intense, you should veg under MH=blue, and Flower under HPS=Red, I thought this was a no brainer, PAR light wave is in between 400-700nm spectrum this is the spectrum plants use. How big is your space, do you have ventilation, these are all very important questions that need to be answered. If your not ventilating forget about any HID both metal halide and high pressure sodium, and stick with the Fluoros.

Peace

biochem1l said:

can someone please explain if it is a misnomer or not?

I thought by having more lights, then youre having better coverage, vs having a large light hanging in the center of the room. wheras the t5 has a bulb going down ever inch or so of plant, so the light is projected evenly. Does this happen with metal halide when its using a reflector? A lot of light is lost when using reflectors.

is this the footprint? the area that gets the most light under a reflector? So by having more points of light wouldnt the room be getting more more even light vs 1 big light?

Click to expand...

ok heres your issue

your focusing on points of light , im completely ignoring this as it means nothing , the footprint of a light is what matters , couple of reasons

1 . the light given out is reflected downwards , this means there is no point of light as you put it but instead a footprint created by the shape of the shade

2 . useable light or intensity , having 3 points of light as you put it ( you dont , you have 3 spreads of light as the light doesnt pinpoint on a single point ) , a 400 m/h has a degree of power , a 600 however has yet more power , over distance this power is lost and the light becomes nothing more than illumination rather than intense light the plant can use , a 600w will cover happily an area of 4 foot square , a 400 hps 3 foot square , a 400 m/h less than 3 foot due to its useable light , so 2 x 600 = 4x4=16x2= 32 square foot , 3x400=3x3=9x3=27 square foot or 5 foot less than the 600 and thats before lights lost due to intensity , now do you get it ?

3 . theres a bloody good reason everyone has set-ups the way they have , guess why ? efficiency , light spread and bang per buck


a graph to show you what lumins to expect at what distance , this is hps remember and m/h is less efficient in the elec is uses


http://www.thctalk.com/gallery/data/500/HPS-Light-Distance-Chart.jpg

getting back to the point , for veg a T5 is simply the best ballance of wattage vrs light output based on what plants require , the spreads good , the ergonomics are good , heats not an issue , afterwards for flower its hps all the way