Fluorescent lighting questions

So I'm using 400w MH and HPS growing right now. I would like to try growing with fluorescent lighting next time. Would that decrease yields or anything? And what size lights would I need for a 39x39x79 tent? Also, do you need to switch out lights like you do from MH to HPS for flowering? Not cfls but T5 lights.
For example,

http://htgsupply.com/Product-GrowBright-2-Foot-8-Lamp-High-Output-T5-With-Choice-of-Bulbs

Would this be big enough for 3x3 or would I need more lumens?

I would think that should be ok, yes you should switch lamps for bloom, 6500k for veg and 2700k or 3000k for flowering, I've been using T5's for a number of yrs now and have decent grows, yes the yield will be less than with MH and HPS, but as I said, decent.

Like significantly different or just a little less?

Really can't answer that, it's been many yrs since I've used MH and HPS, and I do mean many yrs, sorry.

i would say mh/hps yields about 40-60% more from what I've heard...

Definitely less, a good option is to grow under cfl or t5 during veg period, the grow is a little reduced in terms of speed, give it another 1-2 weeks for a large vegging plant, but the energy efficiency blows mh lights away.

Flower with hps lights

this is also my plan for next grow, I want to run clones in veg under cfls to save electricity and honestly the difference between cfl growth and my mh growth has been minimal, but for flower you can't go past hps. Many people would argue that mh is better for veg because they are either in a rush or expect higher yields which is true, but compare if you have the same amount of plant growth and switch to hps in flower, where the plant can double in size anyway, your yields would be comparative I believe.

Look at the highest yielding plants, outdoors. Nothing can go past natural sunlight, the reason why commercial growers produce in green houses is because of this fact, while the logistics of this force many others to grow inside, also due to the timing. A green house or outdoor grow can take up to 4-6 months, where an indoor grow can take 3-4. But if you have a plant outdoors with 1-5 pounds compared to its equivalent inside 1-5 ounces and max of 1-2 pound (long veg), you can see why people choose different sources of light.

its all based on what suites your needs, budget, time etc.

Use you HPS BUDS after using T5 6400k's for VEG.
It's a bit of a backwards manoeuvre....
Usually people graduate from flouro's to HID's....

Maybe you're one of the rare few who wants less buds with decreased density....?


After the flouro crop, what do you plan on using next....?
2 desk lamps and a torch....
Or a January window ledge?

I was just thinking decreased electricity lol that's why I created this thread. To get some info no need to dis me with a smart ass reply.. Actually no I'm gonna go to 600w thanks to the helpful replies above..

cdd10 said:

So I'm using 400w MH and HPS growing right now. I would like to try growing with fluorescent lighting next time. Would that decrease yields or anything? And what size lights would I need for a 39x39x79 tent? Also, do you need to switch out lights like you do from MH to HPS for flowering? Not cfls but T5 lights.
For example,

http://htgsupply.com/Product-GrowBright-2-Foot-8-Lamp-High-Output-T5-With-Choice-of-Bulbs

Would this be big enough for 3x3 or would I need more lumens?

Click to expand...

I wouldn't change a thing regarding lighting.Your lighing for sure..why would you wanna change? It's a pain moving cfl's close in order to maximize efficiency.I did it at start and doing it now vegging..not worth it. Also i would do 2 seperate rooms and spread the lights you already have.You could definitely do 4,maybe 6 plants flowering under this HPS and have a perpetual grow with your MH.Try UB's topping technic..Works like charm..

use a dual arc bulb, it is basically a MH and HPS combined.

qroox said:

I wouldn't change a thing regarding lighting.Your lighing for sure..why would you wanna change? It's a pain moving cfl's close in order to maximize efficiency.I did it at start and doing it now vegging..not worth it. Also i would do 2 seperate rooms and spread the lights you already have.You could definitely do 4,maybe 6 plants flowering under this HPS and have a perpetual grow with your MH.Try UB's topping technic..Works like charm..

Click to expand...

I really don't wanna change I was just thinking about electricity really. And if I had the room I would do two rooms but being as this is my first grow we will see about that later and I've been trying to find a good dual spectrum bulb as I read they get better results?

NorthofEngland said:

Use you HPS BUDS after using T5 6400k's for VEG.
It's a bit of a backwards manoeuvre....
Usually people graduate from flouro's to HID's....

Maybe you're one of the rare few who wants less buds with decreased density....?


After the flouro crop, what do you plan on using next....?
2 desk lamps and a torch....
Or a January window ledge?

Click to expand...

It makes perfect sense to change your lighting according to your needs, maybe he wants to save on power, or has heat issues and can't afford to run air conditioning all summer.

While I agree with you that it's kind of backwards to go from mh/hps to fluro, people have their own reasons. If everyone only cared about density and bud production nobody would be growing inside or in tents to start with, but sticking 20 foot monsters in your garden isn't exactly realistic or legal in most places.

maybe he has a good reason

Matt420Aus said:

It makes perfect sense to change your lighting according to your needs, maybe he wants to save on power, or has heat issues and can't afford to run air conditioning all summer.

While I agree with you that it's kind of backwards to go from mh/hps to fluro, people have their own reasons. If everyone only cared about density and bud production nobody would be growing inside or in tents to start with, but sticking 20 foot monsters in your garden isn't exactly realistic or legal in most places.

maybe he has a good reason

Click to expand...

Thank you my friend lol I just don't wanna raise suspicion with a large electricity bill. I live in a small town I figured it might raise suspicion..

cdd10 said:

Thank you my friend lol I just don't wanna raise suspicion with a large electricity bill. I live in a small town I figured it might raise suspicion..

Click to expand...

Yeh I can understand cdd, my desire to keep my electricity bill lower is more from the fact I don't want to pay a lot of money for higher electricity, our house uses all cfls we turn things off at the wall to save on standby already. I think your 400w is sufficient for your current purposes, plants like more light but with more light comes heat issues, electricity issues etc.

as long as your bill does not spike by more than $100 annually I would not be concerned. Another way is to think ecologically, there are so many ways to save on power around your home, if you have not change all your light bulbs for cfls, rather than using dryer in winter get a clothes horse and wait to dry, turn off all your appliance switches at the wall (you would be surprised how much this saves), charge your phones and electronics at work if this is an option (obviously if this would get you in trouble with your boss or if you own the company you may not want to), turn off lights if your not in the room, tv etc. there are many other ways you can find online, but my power bill is less than $200 every 3 months, with several people living here, so it gives you an idea, used to be $300+

Matt420Aus said:

Yeh I can understand cdd, my desire to keep my electricity bill lower is more from the fact I don't want to pay a lot of money for higher electricity, our house uses all cfls we turn things off at the wall to save on standby already. I think your 400w is sufficient for your current purposes, plants like more light but with more light comes heat issues, electricity issues etc.

as long as your bill does not spike by more than $100 annually I would not be concerned. Another way is to think ecologically, there are so many ways to save on power around your home, if you have not change all your light bulbs for cfls, rather than using dryer in winter get a clothes horse and wait to dry, turn off all your appliance switches at the wall (you would be surprised how much this saves), charge your phones and electronics at work if this is an option (obviously if this would get you in trouble with your boss or if you own the company you may not want to), turn off lights if your not in the room, tv etc. there are many other ways you can find online, but my power bill is less than $200 every 3 months, with several people living here, so it gives you an idea, used to be $300+

Click to expand...

Sounds like a good idea and yes I have switched to cfls I think mine was $240 last month but I used a space heater without knowing it used so much damn electricity lol it was $170 month before that.

I have done hps mh and t5. I had 8 plants 3 gallon buckets. under a ( 8 bulb ,4 foot ) t5 light. it pulled. 15 ounces toped only twice. it was a lazy grow. I would not suggest topping more then once 4 big buds each plant. I pulled total dry weight from this 450 watt light. 15 zips. the buds were tight. very good smooth smoke. but what I did. I ran 2700k lamps for 6 weeks or soo. then changes out the bulbs when the buds stopped getting fat to a 10000 k bulbs. enhances the shinny crystals. now under a 600 hps. I can pull 20 zips. topping the plant so each plant has 8 major bud sites. the mh 1000 watt hortilux I was not impressed for the extra juice. I like the cfl t5 or the hps. now the t5 doooo put off a lot of heat , mabe double then a 600 watt vented hps. so if heats an issue stay away from high powered t5. take my word on this , in the long run my opinion. I run 600 hps until the buds stop getting fat then I add the mh bulbs to get extra sexy looking buds. for the yield to watt ration the hps wins the race. over the t5 . but if your not worried about yield. greed , like me. then t5 are the winner. for got to mention bud quality from hps to cfl. nobody could tell the difference and they loved both . solid buds. both smoked the same. I have been around a wile, so I expect to pull large yields. but an average under a few years experience would only pull 8 zips from and 1 light if they were lucky I used to.

cdd10 said:

I really don't wanna change I was just thinking about electricity really. And if I had the room I would do two rooms but being as this is my first grow we will see about that later and I've been trying to find a good dual spectrum bulb as I read they get better results?

Click to expand...

I understand.High electricity bills are not a good thing.I am using a lumatek 400watt with a ''claimed'' to be dual spectrum.I think it's more feelings than facts..I am planning to get a 250w HPS to veg my new vegetative room..I'll be able to do some comparison in a few months.I'll take what i've read from experienced growers tho..1 400watt,either MH or HPS can go from start to finish.Don't sweat over it..They grow in the fuking shade outdoors..

I don't get why a high electricity bill is a problem but I guess it is. As long as I pay my bill why does it matter how much I use lol

I used 4 85w blue and 4 55w red CFLs I swear to you I had the bushiest plants ive ever had even with MH 600w. plus they can get really close to them. and it saves money on electricity and cooling. I got scared into buying 2x 600w HPS for flower but im gonna try to flower with the CFLs eventually cus they did remarkable thru the veg