Starting up indoor- unique space. LED or HPS?

[rangerjake]

After a moderately successful outdoor grow last summer (only stymied by a cool damp early October and a battle with bud rot) I have decided to go indoors to help mitigate some of the weather challenges and to have a 12mo/yr capability.

I have the good fortune of having access to what seems to be a very excellent growing spot: a walk in mini-room in the back of an attached (not heated) garage. Dimensions of the space are roughly 7ft tall, a bit over 5ft long and just over 4ft wide. I have an assortment of autoflower and full photo seeds en route from Nirvana. Aiming to be up and running by April 2nd (no fool am I).

Here is the core of my dilemma.

The startup cost of LED vs. HPS seems negligible enough. My guess is that for a space this size I'd be using a 600w HPS or a 700w or 1200w LED. I really like the idea of HPS in that here in northern VT having heat generated from a light isn't a terrible thing (especially from October-April) to help bring up the ambient temp in the space- which as I said is in an unheated, though enclosed, garage. I have been leaning more towards LED recently (ViparSpectra) due to reduced electric use, no need for ducting/fans, and also because I have a tall enough space that I can really allow the head clearance that can be a limiting factor for many using LED.

My main question is what, if any, ambient heat bump I can expect from a sizable LED panel? I plan on having about 4 plants going in the space- would the 700w or 1200w ViparSpecra be most optimal for this setup? I'd be interested to hear the thoughts/concerns/experiences from anyone who can speak to any of this stuff. Love this forum and site- really the best place I've found to get schooled up and get going. Thanks to all!

[KTM690]

Hi there fellow vermonter the hos will help with the heat for sure not a lot of heat off the led. But a Oct thru April grow with northern Vermont temps might make u need to heat that space up when lights are off. Even if u do 24 hrs with autos still might get cold on these below zero nights

[Farmall]

I’m an sure in an un-heated space you will need to run some heat when those lights are off. Don’t ask how I know about those temperatures but Richford, Enosburg and North Troy all come to mind at anywhere from -30 to -45 Fahrenheit . There is little chance of maintaining night temps above 65 should those temperatures swing into those zones in winter this year. Had an old army friend who use to keep the filaments on old transmitter tubes lit to get extra heat in his bedroom... yes, they were big transmitter tubes

[rangerjake]

Hi there fellow vermonter the hos will help with the heat for sure not a lot of heat off the led. But a Oct thru April grow with northern Vermont temps might make u need to heat that space up when lights are off. Even if u do 24 hrs with autos still might get cold on these below zero nights

I am mostly planning on conducting growth in the space from April-October. Trying to grow out there midwinter will be something that even the full heat of HPS won't be able to offset (as I am sure you know after the last few days of below zero temps). Certainly there are the odd April and October days where temps can only be in the 30s-40s. But the majority of the grow will be during typical outdoor growing season.

[Toker1]

A watt is a watt. Led lights create heat just like an HPS light does. Air cooled HPS technology is superior to heat sink LED technology when it comes to heat management.
led heat management is only superior to HPS in a bare bulb situation.
also, reduced electrical use = less yeilds. The promises cheap LED light manufacturer’s make are not realistic.

[Bond]

So led is not going to give you the big yeilds like hps mate.

[Toker1]

Bond for most led lights... I agree. All affordable LED lights are just not efficient like HPS is. There are truly efficent higher quality LED lights available though... if you are willing to spend a few grand per light fixture, you can find truly efficent LED’s that are higher yielding (on a per watt basis) than HPS. Only issue is that spending that type of $$ is hard to gain back your return to make the grow actually profitable. So HPS is king when we are talking efficency and profitability both together in the same function.

[gbauto]

I grow in a 5x5 closet in my home with the same headroom. Using a pair of 320W Vero bars over 4 17gal UC totes. As others have stated, every watt of power you use in the room has the same effect at raising room temps. Advantage of using current tech led's is they create more light for each watt used. Disadvantage is the initial cost compared to a HID fixture. If I had the ability to exhaust the heat from a HID fixture, I would run a 1k HPS vented fixture for your 20 sq ft room-It will provide enough PAR to grow some AWESOME dank.

[Toker1]

I agree...but he said Viapar Spectra. So not the efficiency of a higher end LED. So I don’t believe the higher light output statement comes into play here with this specific light fixture.

[Smokesteve]

I've grown with Vipar and Mars, I switched to a dimmable 600 watt HID setup that can do metal halide (veg) and HPS(flower). For your size space you could go higher watts. The outcome with HID will destroy cheap LED.

[Budler]

I have 2x900w vipar. Unfortunately their footprint is very small. So min 1 light / plant. They are good for veg but they are light on the red spectrum that you need for the flower.
I changed to mh/hps combo, you cannot compare it.

Also the 900w Vipar draws around 350 from the wall. And as other users said, watt is a watt.

And they are running around 30-32celsius so you’d definitely need a heater if you go with the leds.

[rangerjake]

Great input! Seems the MH/HPS combo is unanimous over the LEDs. One other consideration is the potential to daisy chain 2 700w LEDs and take one down to use inside during that colder midwinter stretch. This is probably something not possible to accomplish with the HID. This consideration is far down the list of priority.

Follow up question that gbauto started to address; for the space and what I am trying to grow (about 4 plants at a time) is it worth it to go 1000w, or will 600w get the job done well? Fully understanding more watts equals more output- certainly that holds true up to a point and that eventually there is diminishing returns. Just trying to gauge how much greater a yield would be under the circumstances compared between one and the other taking into account costs.

Thanks everyone.

[Toker1]

600w HPS covers a 4ft x 4ft space well.

[gbauto]

A typical 600w HPS produces 1100 umoles PPF so it can provide just under 600 umole/m2 PPFD for the space he's trying to light. It'll grow but he would do better with more oomph...

[Toker1]

gbauto not necessarily. 1000w in a 4x4 can waste light by shining directly on the walls. I have seen this before. If you want more oomph best to rock the cfl or LED lights in conjunction with the 600w HPS. That way you light up all the shadow spots, with out wasting electricity by shining light directly into your grow room walls.

[Potted]

600watt hps is the most efficient to run watt for gram of weed😁till recently I’ve found a 315 watt LEC that pulls 315 from the wall and has a more intense light imo than the 600 and no telltale yellow light witch is a dead giveaway to other’s. Lol

[Toker1]

Phillips 315 CMH elite bulb is rated for 34,440 lumens.... eye hortilux 600w HPS is rated at 88,000 lumens. A yield lab DE 600w HPS is rated at 96,600 lumens. I got this information from the bulb manufacturer’s website.

[FlyingDutchPaddy]

I'd suggest if going with LED, is to get 2, or even 4 seperate lights, over one large one.

Reason: you can position each light over your plants.

I've got 1 400W equivalent LED for my tent (4x4ft) and a DWC system that unfortunately has the reservoir right in the centre. The res sits directly under the light.
With 4 seperate panels, each plant would have a light directly above it.

Thats my opinion.

Good luck with the setup!

[Rdr123]

I just did a grow with s 1600 watt pro mars hydro led. It runs at 750 watt. It’s about $600 new. It claimed to flower a space 5’x5’. It was really only good for 3.5’x 3.5. The electricity was almost the same as using hps . Because I had to add 2 more led lights to make up.

[Mr.furley]

1200w ViparSpecra can cover 4.5' × 4.5' that is a 350$ unit that has a actual draw of 524 Watts from the wall which is less the a 600 watt hps and your footprint can hold a 1000w Hid.
Just don't thing you are going to get a equivalent to an HID light unless spending big bucks for Led.