Posted on by Jason Gibson


As lighting technology progresses hydroponic grow lights have come a long way! A few lighting examples that are commonly used in indoor growing are:

HPS (High pressure sodium) Are predominantly used in the flowering phase of the plants life, the spectrum output is usually between 2000-3000K (Kelvins) which we see as a yellow, orange colour.

MH (Metal Halide) Used mainly for the vegetative phase as this type of lamp is better for growth the spectrum is between 4000-6500K which we see as a blue, white colour.

T5 (Fluorescent battens) T5 lighting is used to germinate seeds or propagate our cuttings, it is a fantastic light to raise your seedlings before transitioning them to something with a little more intensity.

CFL (Compact fluorescent lamp) Similar to T5 lighting, used for the same reasons and they also offer a little more power, which allows the grower about 2-3 weeks under this light before needing to transition.

LEC (Light emitting ceramic) A brand new technology, these lights emit more micro-moles per watt than any HPS or standard MH globes, which means the spectrum is as close to natural sunlight as you find in a lamp. They can be used from start to finish and are available in 3000-4500k spectrums, they only come in 315W and they offer the same output as a 600W, so more usable light and less power! They also state that essential resin production increases by up to 40%

LED (Light emitting diodes) LED technology has been around for quite some time; there are many mixed reviews as many of them read very well on paper. The LED’s usually come in as an all in one, offering compete spectrums,3-5W Diodes (some even have 30W COBs mounted in the center) and are available in multiple wattages, most professional growers only ever use them as supplementary lights in flower alongside a HPS.

LEP (Light emitting plasma) LEP is another brand new technology released by the Dutch leaders in lighting. The power usage is very favorable for the power conscious grower, but their main benefit is they offer a very unique spectrum 10,000-14,000K – What this spectrum does in vegetation is harden the plants off, which in turn helps support more weight in flower, used in alongside a HPS in flowering the results are amazing, the light is mimicking when the sun becomes perpendicular to the earth, in turn emitting a white, purplish ray… this spectrum is directly responsible for increasing the potency of cannabinoids, poliflavinoids and terpenes! Potency is increased by up to 25%. This technology is also fantastic for power using only 270W!

Photoperiods required for growing indoors:

24 on 0 off (Usually most propagation rooms are powered non-stop)
18 on 6 off (Most commonly used in vegetative phase)

12 on 12 off (Used to initiate the flowering response)

12 on 1 off 5.5 on 5.5 off (This is called gas lantern routine, and should only be done from the start)



240v Magnetic, cooper coil used to charge the lamp and ignite/strike the lamp.


240v Digital, many different types available, and these work by sending digital pulse to ignite the lamp, start up time is usually quicker and 10% of power is saved from switching from magnetic - fan-less in design are the better ones, if it has a fan in it that means it needs cooling down.


400v – This is where the money is! These lamps have a 3-phase processor built into the unit, which basically means an 8% saving on power versus same wattage equivalents, and 22% More useable light output for the plants, these lamps are also that powerful that our minimum distance between mounting and canopy MUST be at least 1.2M above! No more 8-12 inches, the footprint that comes out of these lamps is so intense it has to be seen to be believed! Everyone who has this technology have doubled their yields, some have tripled! So in a nutshell the best digital ballast and lamp on the market will only do a 3rd of what this lamp can do!


SO…240v (volt) are the old, these are the stock standard ballasts, and have been around for years, all old magnetic ballasts and entry level digital ballasts will be powered like this.


AND… 400v are the new (Gavita being the clear leader) and will double if not triple your yield, one 1000w lamp will cover 2sq/m, in addition to that it is worth noting that the leaders in medical marijuana cultivation in the USA only use these lamps with the LEP technology.

Old Technology: Micro-mole output of standard 240V 600W HPS is around 500-798 (1-2g per/w)
New Technology: Micro-mole output of standard 400V 600W HPS is around 1800-2100 (2-6g per/w)

Wattages and applications:

3w-30w = high spectrum but entry level powered lighting (LED)

24w-250w = propagation of cuttings, housing mothers and germination (T5 & CFL’s)

270w-315w = to harden plants off and to increase resin production and potency (LEP & LEC)


400w = Used to vegetate plants, most would veg under a 400w MH (HPS available in 400w too) simply because you can get the lamp a lot closer without loss of light (5 ignition points in arc), however they are only considered entry level PAR (photosynthetic active radiation) so most growers choose to transition to much stronger lamp before going into flower.


600w = The most preferred lamp for the indoor grower, more usable light than any other wattage available, great lamps for the hobby grower and would cover 1sq/m. (Available in HPS & MH)

750w-1000w = the pro growers lamp of choice, 2sq/m coverage, highest yield (Available in HPS & MH) most growers run the 1000w HPS in flower)


Growing temps under these lights vary between 23-32 degrees (27-28 being optimal) if the grower finds temps are climbing, the way to combat this is basic ventilation (exhaust & intake), this will help the grower optimise his/her climate.

And last but not least!

There is no benefit using any of the HID lamps if the grower is not correctly supplementing CO2 (Carbon dioxide) plants consume Co2 which in turn increases photosynthesis, so if you’re only bringing in ambient amounts of co2 the plants will consume this almost immediately, the only downside to this is that once the co2 is depleted the plants can no longer photosynthesise light (grow) which, makes them grow like an outdoor plant (only indoors and in a perfected environment) triple the levels and triple the growth rate, which will triple your plants yield. If there is not a correct exchange of air within the room plants will very quickly start transpiring, confusing growers as this usually results in deficiencies which get incorrectly diagnosed. Plants are 90% carbon and 40% of their end weight is CO2 attributed.