T5 light intensity chart

Kingrow1 · Feb 26, 2016

Ive been using this chart to great effect with my 96watt 4 way t5 lightwave unit, kind of makes more sense than just putting small plants a couple of inches off, with just half my bulbs im at 25" for seedlings and could probably push a bit futher away with the rest on.

Strange how most want to be 2" of the bulbs when the real data suggests this is FAR too close and too intense for photosynthesis. Im guessing im wrong and everyone else is right but ive run the figures and they seem to work just fine.

At 2 foot with 2 x 24watt t5's im at just over 9mols of light a day. People can agree or disagree all they want but hard facts and data mean a lot more in my book. Sorry if your the kind of grower that when things get technical you run for the hills.....

Kingrow1 · Feb 26, 2016

And here is a guy checking his twin t5s with a par meter, even approaching 20" away the par meter is still reading 100 micro mols.

100x16x60x60/1000000 = 5.76mols at distance which is your daily light intergral for these particular bulbs

since1991 · Feb 26, 2016

Good post

bryan oconner · Feb 28, 2016

that's why most t5 users have the bulbs almost touching there plants . get the most par .

Kingrow1 · Feb 28, 2016

bryan oconner said:
that's why most t5 users have the bulbs almost touching there plants . get the most par .

Im not most t5 users ;-)

Corso312 · Feb 28, 2016

My T5's are 10-14" away..I veg with them.

Corso312 · Feb 28, 2016

bryan oconner said:
that's why most t5 users have the bulbs almost touching there plants . get the most par .

I run a 400 watt 8 bulb fixture, its hotter than ya think..4" is probably the closest you can get.

bryan oconner · Feb 28, 2016

idk guys . when I used to use t5 . I now use mh much faster growth my opinion . I used to have the t5 an inch away never burnt them. in fact only time they used to burn when the leafs starting to grow onto the bulbs. I used to us a 4 foot 8 bulb badboy set up

whitebb2727 · Feb 28, 2016

Corso312 said:
I run a 400 watt 8 bulb fixture, its hotter than ya think..4" is probably the closest you can get.

I veg and flower with an 8 bulb 432 watt fixture. It gets hot no doubt. It will burn plants. I run them at 8-12 inches away.

bryan oconner · Feb 28, 2016

strange mine never burnt or got hot. must of been the fan I had running . kept it cool .

bict · Feb 28, 2016

Interesting read. I'm just about to buy a 110w two bulb t5 fixture for 25 seedlings. Keep em close or have a bit of distance ? Conflicting opinions.

Corso312 · Feb 28, 2016

bict said:
Interesting read. I'm just about to buy a 110w two bulb t5 fixture for 25 seedlings. Keep em close or have a bit of distance ? Conflicting opinions.

Don't cheap out .. Get the 4 or 8 bulb.

bict · Feb 28, 2016

Corso312 said:
Don't cheap out .. Get the 4 or 8 bulb.

Short on cash man, just moved and started uni/paying for uni.
I only want to get the seeds big enough to put outside. 4-6 inchs.

Corso312 · Feb 28, 2016

bict said:
Short on cash man, just moved and started uni/paying for uni.
I only want to get the seeds big enough to put outside. 4-6 inchs.

Ahh I hear ya, good thing you got a nice harvest in a few weeks.

shorelineOG · Feb 28, 2016

Corso312 said:
My T5's are 10-14" away..I veg with them.

Have you ever tried the power veg t5 bulbs? These are expensive but are worth it.

Corso312 · Feb 28, 2016

shorelineOG said:
Have you ever tried the power veg t5 bulbs? These are expensive but are worth it.

I have had this fixture for like 4-5 years n never replaced a bulb..I will look into though.. For now the nodes are stacked tight n still workn great.

bict · Feb 28, 2016

Corso312 said:
Ahh I hear ya, good thing you got a nice harvest in a few weeks.

Mate, don't be like that

Budley Doright · Feb 28, 2016

I have never burnt a plant running T5's unless they actually touch the plant and at times some of the stretchy ones get close, real close lol. I do tend to keep them 12" away though just so I don't have to lift them daily

. As for better growth with my MH's I'm not sure but yes they work very well also but it's 600 versus 216 watts and power is pricey here.

whitebb2727 · Feb 28, 2016

bryan oconner said:
strange mine never burnt or got hot. must of been the fan I had running . kept it cool .

How many bulbs? How big of a space?

T5ho gets hot.

My cab is 2x4x6. That's an oven.

I also killed some seedlings because of what I read online. I've read many times if your hand is OK under the light then the plants will be OK. Bull shit!

Maybe one or two bulbs. Not 8 that are double stacked. My fixture has 8 bulb in the same size others put 4. It will burn new growth less than about 8 inches. It needs to be over a foot away for young plants.

whitebb2727 · Feb 28, 2016

http://www.amazon.com/4lamps-DL844s-Fluorescent-Hydroponic-Fixture/dp/B00HEYCRI8B00HEYCRI8

http://www.amazon.com/8lamps-DL848S-Fluorescent-Hydroponic-Fixture/dp/B00INGMTPW

http://www.amazon.com/12lamps-DL8412-Fluorescent-Hydroponic-Fixture/dp/B00PJ5T8F4

I own the 6 and 8 bulb units. They work great.

bict said:
Short on cash man, just moved and started uni/paying for uni.
I only want to get the seeds big enough to put outside. 4-6 inchs.

The 8 bulb is 432 watts and it gets hot.

shorelineOG said:
Have you ever tried the power veg t5 bulbs? These are expensive but are worth it.

Corso312 said:
I have had this fixture for like 4-5 years n never replaced a bulb..I will look into though.. For now the nodes are stacked tight n still workn great.

I plan on getting some of those. I got to see some in action in a hydro shop and they look like a good lamp.

T5 light intensity chart

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