What kind of grow light

Hey guys wondering if someone can give me some advice on lighting. I’m looking to grow 2 or three plants. Wondering what sort of lighting I’d need for that without breaking the bank account. Advice please!

Welcome to the forum. Here is the light expert @dbrn32.

Cost effective and proper spectrum, my choice is CMH 3100 k for flowering and 4000 k for grow, the bulbs are interchangeable with the ballast, therefore, going from grow to flower is as easy as changing the bulb! Philips has a reputation for making the best bulbs, they’re the ones that invented CMH especially for agriculture.

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Thanks bro. You have a for them on amazon?

I mix match my reflectors to ballasts of my choosing, I use these reflectors for their deep penetrating focus, however I would not use them without a light mover, I’d opt for a wide angle reflector if it’s to be stationary.
Links are in-bedded in the photos.


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Awesome thanks for the info

I think @Shatter has you on a good path for lighting. I just wanted to add - before you choose a light, you need to know what size your grow space will be to calculate just how powerful/how many lights you might need. I would suggest you start thinking about the grand scheme of everything you will want/need for your setup.
As a general guideline, a 2’x4’ tent is good for 2 plants and a 3’x3’ tent is good for 3 plants. But if you have the space and any thoughts you might someday want to grow more, I highly recommend considering a 4’x4’ tent. They are vastly popular, so there are many to choose from. They also give you a little more space to maneuver around amongst your plants.
Mind you, a 2’x4’ is perfectly fine. I just want to bring up further goals you might have as it could save you money in the long run from buying a lot of stuff twice.

Once you have decided what your grow space will be, then you can decide how much lighting, ventilation, environmental controls, etc. will be appropriate for the space.

Oh - you should also decide (and share with us) what your budget is. That also helps us to choose the best products for your price range.


One CMH bulb is sufficient for 9 sq ft (3’X3’) a 4x4 tent would serve you good and leave a little extra space for climactic redundancy (natural convection and radiation by volume).

Will do! Thanks for all the great advice. There is one tent I was looking at on amazon its measurements are 48x20x60 seems pretty good it’s by Vivosun.

Giving us your specific grow space, lighting budget, and grow expectations will help hone our recommendations.

Hps/cmh lights can put off a lot of heat. I’d be wary of putting them in a small (height) tent. Great lights for the money, but they do have shortcomings.

Quantum boards from hlg are fantastic plug and play lights with high efficacy and very little drawbacks.

Diy builds with light strips or qb’s can give you all the positives of plug and play qb’s, at a customizable size and a lower price

Cob lights are also a good alternative. They’ve been a little slow keeping up with qb’s tech, but are available as plug and play or diy.

Blurple lights from amazon will do the job. They aren’t expensive, but they have very low efficacy and are usually marketed to be more powerful than they are. I don’t recommend this type of lighting.


Just put a HLG 260xl rspec in a 2x4x7. Very pleased with the reaction from the ladies. Praying all the time which was hit and miss with the blurple.

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I also use 2 HLG 260xl rspec kits in my 4x4. My girls LOVE these lights.

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I built a 300 watt Bridgelux Vero SE COB for my 2x4 tent. It raise ambient temps only 2.5 degrees. A 315 watt CMH raised temps 14 degrees… CMH is good but heat is always a focal point :skull_and_crossbones:


@dbrn32 hey bud do you have any insight on the height and power % for the seedling into early veg? Thanks

Start at roughly 24" at 50% power (A dimming driver turned almost all the way down). Adjust as needed to keep seedlings happy. You can gradually increase power as plants start to mature, but no reason to run over 75ish % power on veg schedule.


Hey man just ordered my lights. My understanding early seedling light should be relatively close couple inches away from seedlings

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That advice assumes fluorescent bulbs. The heat from any HID lamp will likely cook any tender seedlings if they’re that close (2-12”).

Using the back of your hand to represent the seedling, play with distance until it seems comfortable indefinitely. Unless anyone else has advice on the subject, that’s the method I’d use.


Had them at 20 and they where bending the knee tapping out :joy:… that was also at about 50%. Raised to 24 and have the power just a half turn from being at its lowest point. The amazon blurples you could possibly do that

Lol. I have have my tent coming in right away. Hopefully my set up works. Have a 1000w unit coming in I better be careful not to fry the girls lol

I know you already pulled the trigger, but lemme make a counteroffer just in case you’re able to return that 1000w light.

Jorge Cervantes advocates using more fixtures at lower wattages. The idea is you’re evening out the coverage, instead of intense hotspots followed by rapid falloff. Light movers can negate that issue, but 2-600w fixtures would give you more options and better coverage. You might want more options for vegetative growth too. Like a 400w metal-halide.

You have to consider the cost of delivered power (my rate is .07, but effectively I pay .23). Will you always wanna crank that 1000w ballast, even during vegetative growth? 3-400w ballasts would let you scale the light to match your growth.

How big is your new tent with that 1000w light?

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