When 400w is the LIMIT of wattage, COB or MH/HPS?

Legal medicinal grow, basement.

Will probably try to convince roomies to allow a 4x4 tent, but may go 3x4.

DWC hydro in 17gal containers.

So far 7 normal seeds popped and unsure of sex (~3 weeks weak fluoro)

Will be buying light(s) very soon.

Had previous positive experiences with weaker 150/250W HPS in small spaces, but didn't appreciate heat.

Will be limited by electric bill (don't want too big of a spike).

Please submit your advice, links to journals are appreciated, specific model recommendations appreciated

ideas so far include:

Two of these: https://www.amazon.com/COB-GROW-Spectrum-Hydroponic-Greenhouse/dp/B01H2WNR6M/ref=sr_1_15?srs=14689402011&ie=UTF8&qid=1473903953&sr=8-15

or 2x Mars Hydro 300....

I think you just opened a can of worms. some people here are in love with their lights and think any other kind of light is junk. but each type of light requires slightly different growing styles.you have experience with HPS lights. maybe you should stick with what you know. the LEDs you are considering use low quality bridgelux diodes and do not last. they are about as effiecient as CFLs. IM a T5 growers myself and those of us who know how to grow with them have good results so im not an HPS grower telling you that nothing else will grow good medicine. just suggesting you stick with a light that fits your growing style. if your heart is set on LEDs then spend the money to get high quality cob fixtures. anything less would be a waste of money.I have tried LEDs and have a mars hydro 300 collecting dust in my shed right next to some DIY cob fixtures (cree 3070, vero 18, citizens) I use what works best for me and you should do the same (use what works best for you. not necessarily what works best for someone else)

I was LST/scrog-ing before I knew people were calling it that, so I like to double-FIM or Mainline and create 4/6/8 large colas per plant.

Will pick best 2/3 females that I get from the 7 I have going now. What is your GPW with T5 maurice?

Why no use of the MarsHydro? Want to send it to an intermediate grower?

EDIT: The only reason I thought of staying away from a 4-ft 6-bulb T5 was light penetration. Do you get good growth 1ft+ down?

GreenLeafKief said:

I was LST/scrog-ing before I knew people were calling it that, so I like to double-FIM or Mainline and create 4/6/8 large colas per plant.

Will pick best 2/3 females that I get from the 7 I have going now. What is your GPW with T5 maurice?

Why no use of the MarsHydro? Want to send it to an intermediate grower?

EDIT: The only reason I thought of staying away from a 4-ft 6-bulb T5 was light penetration. Do you get good growth 1ft+ down?

Click to expand...

I get about 0.7 gpw in a 4ft by 2 ft closet grow using a 4 bulb light these picture are at 16 20 and 26 inches from the light. my mars hydro lost 4 diodes in the first month and lost 7 diodes when I pulled it out and replaced it with a 2G11 fixture (2FT by 2FT grow closet) I would never give junk to another grower. my morals won't allow me to. for a 4 ft by 4ft grow space you would want 2 4 bulb fixtures to get uniform coverage. check out club T5 and RM3s post for more information on what T5s can do. there are much better T5 growers on this site. im just an average PU MMJ growers. I am no expert

GreenLeafKief said:

I was LST/scrog-ing before I knew people were calling it that, so I like to double-FIM or Mainline and create 4/6/8 large colas per plant.

Will pick best 2/3 females that I get from the 7 I have going now. What is your GPW with T5 maurice?

Why no use of the MarsHydro? Want to send it to an intermediate grower?

EDIT: The only reason I thought of staying away from a 4-ft 6-bulb T5 was light penetration. Do you get good growth 1ft+ down?

Click to expand...

You wanna know about T5 growing check out @RM3

@RM3 I've read through 20-30 pages of your journal but it seems as if its a very high wattage, yes/no? At least 12 tubes?

I thought of using a 6-tube instead of a 4-tube, to end up at 324 watts, switching to 3000K to flower. Is this enough to yield ~250g + ?

GreenLeafKief said:

@RM3 I've read through 20-30 pages of your journal but it seems as if its a very high wattage, yes/no? At least 12 tubes?

I thought of using a 6-tube instead of a 4-tube, to end up at 324 watts, switching to 3000K to flower. Is this enough to yield ~250g + ?

Click to expand...

It's 18 bulbs

I'd have to say no

Get a COB LED, T5's suck badly they are one of the least efficient lighting sources and make a ton of heat, you would be better off with a HID than T5, and COBs are even better than an HID light if you can afford them.

I'm in the same boat my first choice is a led my pocketbook doesn't agree second choice 315 lec/ cmh & the cheaper cost of the 2 both should outperform the 400 hps which does work

Ok guys, so what I'm hearing is if you're going to use T5 you need to go big or go home, use 3 different bulbs and will be using 600+ watts anyway. I'm surprised the T5 generates so much heat. @mauricem00, have you seen heat issues with your ladies at about 14-18inches from tops?
Looking at @RM3 's grow journal it doesn't seem like he is having issues, could be due to the room size hehe. He certainly has no issues with hus plants not liking it.

Now, budget is not a HUGE issue, but I still want value.

Would two of these do the trick? https://www.amazon.com/COB-GROW-Hydroponic-Vegtative-Flowering/dp/B01FJ7Q0KW/ref=sr_1_14?srs=14689402011&ie=UTF8&qid=1473961819&sr=8-14&keywords=COB+led+light

If y'all were forced to buy a COB or CREE led right now for your setup and had a max of 400ish watts, what would you use? Grow space will again be 3x4 or 4x4.

GreenLeafKief said:

Ok guys, so what I'm hearing is if you're going to use T5 you need to go big or go home, use 3 different bulbs and will be using 600+ watts anyway. I'm surprised the T5 generates so much heat. @mauricem00, have you seen heat issues with your ladies at about 14-18inches from tops?
Looking at @RM3 's grow journal it doesn't seem like he is having issues, could be due to the room size hehe. He certainly has no issues with hus plants not liking it.

Now, budget is not a HUGE issue, but I still want value.

Would two of these do the trick? https://www.amazon.com/COB-GROW-Hydroponic-Vegtative-Flowering/dp/B01FJ7Q0KW/ref=sr_1_14?srs=14689402011&ie=UTF8&qid=1473961819&sr=8-14&keywords=COB+led+light

If y'all were forced to buy a COB or CREE led right now for your setup and had a max of 400ish watts, what would you use? Grow space will again be 3x4 or 4x4.

Click to expand...

I have no problem with heat growing in a 4ft by 2 ft closet with no ventilation except what leaks thru the door.growth slows down if I get my lights closer than 6 inches from the plants but on this grow one of my plants stretched a lot more than others so with my lights 6 inches above that plant my light is 14-16 inches above my other plants.you only need 6500k and 3000k bulbs to grow good plants. using specialty bulbs provide a very small improvement but some of us like to experiment with them.the led crowd likes to exaggerate the negatives with T5s because they are the most popular light for small scale indoor growing and most garden centers use T5s or T8s on their indoor grows replacing MH bulbs. HPS are only used as supplemental lights on outdoor grows during winter to give plant a longer day. I have been able to find information on the grow rooms at 3 MMJ dispensaries. the one in northern nevada use a high end 3 band (450nm.630nm and 660nm) led. the one in southern nevada and colorado use T5s. the colorado dispensary claim that their customers demand flouro grown flowers because they taste better. T5s do nor require blowers like HIDs or cooling fans like LEDs my grow room temperature with a 4 bulb 4foot fixture in a 4ft by 2ft by 8ft closet raises 4 degrees with my light on with no vent fan or air intake.just a small 9 inch table fan in the room to circulate the air. I open the closet 2 or 3 times a day to spray my plant with water because of the low humidity up here in the high desert but thats the only air exchange my grow closets get.if I was forced to use cobs I would use citizen 4000k 90CRI diodes.these high CRI diodes have a red peak at 630nm. lower CRI diodes have a red peak at 580-590nm and produce a lot more yellow and green light which plants do not use efficiently. a 4000k has the highest output at 470nm (chlorophyll B) of diodes in the 5000 to 2700k range and enough indigo( royal blue 445-450nm) to reduce stretching. these diodes actually gave me the best results in my led test but without UV light insects (spider mites) were a serious problem and I needed to add cal-mag supplements. yield in this test was a little under 0.5 GPW.and quality (THC and taste) was lower. in your situation your grow room size is borderline and LECs may be your best option if you can manage the heat. they give a much better spectrum than HPS or MH bulbs and at that power level CMH bulb equal or exceed the efficiency of T5s. remember that luminous efficiency is not the same a radiant efficiency. what looks bright to us may not look bright to plants

400w is all you can use ?

I would go with 50w or lower cob units and spread them around

or 1w leds or smd leds may even be better

you have to go for max gpw, I`d use tons of lower power leds and side light to fuck

maybe a few 20 to 50w cobs up top, then walls of smds

if you decide to go MH/HPS do not go dimmable as it changes the light spectrum.

Thanks @dirtpower, always good to know for the future, something I haven't ever seen on a forum. So, even for bigger spaces, never get a dimmable 600w etc? curious.

Based on responses I am unsure if I should shrink the grow area to 3x3 in a standard budget grow tent.
That will obviously eliminate Fluoro unless I get a monster 8-bulb 2-foot-wide rig

Thanks to @mauricem00 and @RM3 for quick responses. Due to both your input I have eliminated some of the options.

Summary of Cons:

HID - I expect a 400w to be too hot, and on the border of using too much power.
T5 4foot - RM3 claims even a 6-bulb @324w is too weak to grow well with 3Ks for flower
COB LED - expensive at the start, potentially requires CalMag, potentially requires extra UV light to kill bugs?
CMH - seems like $350+ to start up, potentially too hot, quite tall-ish?

Any CMH fans out there, for a 3x3 or 4x4 space?

I contacted the lads at Timber ( http://timbergrowlights.com/products/grow-light-kits/ ) and they said a 300w COB doesn't really cover a 4x4.

So, it would be $500 for a legit 300watt COB setup. hmm.

you could find some 30w to 150w double ended cmh lamps and use them

or yeah just build a 300w to 400w cob set up

should only cost between £100 and £300 to make up a 400w cob lamp

just get like 6 to 8 100w 3000k cob chips

some heatsinks

some fans

and 300w to 400w of drivers

smd leds around the sides and top with some 30 to 60w cobs up top would probably yield best

you won`t have any issues with rot or bugs using 3000k or 5000k cobs, well no problems you would not get with mh anyway keep your humidity temps and airflow good and clean the grow and spray during veg and you`ll have no issues

a 300w to 400w induction unit may do, you were thinking of t5`s, 200w to 400w of induction is pretty normal to use as a flowering lamp and they can pull a good yield I would say somewhere between .5g and 1gpw is achievable with induction sure like any kinda lights theres some people out there claiming to get more

a 300w induction bare bulb gets about as hot as a 400w mh in a cool tube does with a 1500cmh fan on it

.

What the yield difference be between 600w hps vs a 300w cob an area it covers

Update: I think I may be going for a half-DIY setup - it is built for me, I just need to frame the 4 COBS in a way I like.

www.cobkits.com

Pricing is just unbeatable compared to Timber.

For ~$500 I will have a 4-COB setup, dimmable. Each with their own driver. Each COB can go to a max of 300Watts but is not efficient at higher loads.

This means I can idle all 4 at 33% power and get 400watts of extremely efficient LED light, and once I move to a larger space I can crank them to 600, even 640 watts total and have them not break a sweat.

I feel as though this setup @300-400w + Fluoro during Veg, then full blast flower, may be unbeatable in a 4x4 scrog.

@THE KONASSURE what is your opinion mate? You mentioned potentially lower prices, but this could solve my low-available-power-now but maybe-more-later problem

RolllingStone said:

What the yield difference be between 600w hps vs a 300w cob an area it covers

Click to expand...

600 hps, 1/4m to 1msq, 300g to 600g some inventive people seem to claim 1kg using on hps in a 1msq area, that`s always 2m high, probably if you do vert its doable who knows

300w of cob, you`ll cover 1/4msq to 1/2m sq, you could pull 300g maybe more if there good leds and everything is spot on

Normally space, heat and airflow become the issue before power use

If you have over 1m x 1m to cover and want to go cheap use a 600w or 1k hps in a cool tube

if you want even coverage and less hot spots then 200w to 50w cobs

hard to know what`s best without actually walking the grow room and making the choice myself your the asshole that has to go in there and water and prune everything..............