I’ve been growing for years, and began using HIDs. When I began I bought a cadillac system. Airflo hood, glass reflector, internal fan to reduce the heat.
It’s served me well, but lately I’ve been considering making a switch. I use 1000w MH for veg, 1000w HPS for flower.
I use a digital dimmable ballast, so I can regulate light intensity during the seedling phase.
But swapping out bulbs is becoming a pain. Even with the glass shield, it can get hot. That’s a concern when growing certain strains that grow tall, and grow right into the light. I’ve had some beautiful buds get cooked.
If I were to switch, what watt LED should I look at? My tent is 4x4, and I usually grow 4 plants.
In looking around,
I see some really impressive grows using only 350-400w LEDs.
Do LEDs produce the same hard buds that my 1000w HIDs do?
I do like the idea of simply turning on the light for a new grow, and only having to regulate a simple dimmer switch, and not constantly changing bulbs.
Look for lights built with Samsung LM301 series diodes. In terms of efficiency, note the following:
LM301b: first generation of the most recent models
LM301h: second generation
LM301 EVO: 2nd generation +
The LM301b model is fine if budget is a concern. The later models only offer ~5% improvement increments.
I would shoot for a minimum of 640 watts for a 4x4. It will achieve PPFD minimums. If you want better from your plants, then do what is necessary to increase PPFD. I run my plants with LM301b diodes at 1,100 PPFD at each plant’s canopy. It takes 3 HLG LM301b panels to achieve that PPFD.
Do you know what PPFD your current HPS setup produces? HPS was what my old plug used (RIP) back in the day and I know it can grow heat but going to a LED that makes the same or more PPFD in your setup, with the right light spectrum can definitely make buds just as good if not better using less energy to boot. Light maps for the good LED companies are usually out there to help make a decision.
If you get the right fixture you will do plenty good in a 4x4. The biggest difference is leds don’t have the ir wavelengths that hps has, so you don’t see as much internodal elongation with most led fixtures that you’re probably accustomed to with hid lights. The plant shape continues more like mh through flowering. Your buds will be plenty hard but your plants will look a little shorter and fuller.
Hitting the easy button would be to get someone +/- 600 watts from horticulture lighting group. Whichever you decide may or may not include dimming but they’re all capable of dimming. Tried and true products with best customer service around. And you’ll never change a bulb again.
Something else I failed to mention. My tent is in an unheated spare room. In the winter the room temps run between 55-70*.
However inside my tent while running my HID it’s a toasty 90* with the exhaust fan off, a constant 75* with the exhaust fan on low.
How much would an LED heat my tent under those conditions?
Leds produce very little heat you might need a space heater in the colder months
Honestly my main tent generally stays a few degrees warmer than the room its in but my secondary tent doesn’t have an exhaust fan its usually about 10 degrees warmer than the room I usually open it to vent the excess heat which dissipates pretty quickly once I do
I’m currently running one light in my 8 X 8 with canopy temps running around 78F daytime. The space is in my basement at a constant 65F and manages fine. If I energize all four lights my 6" AC/Infinity fan runs hard to maintain 82F.
Like @dbrn32 said; somewhere in the 600 watt region should do. Latest generation LED’s have about 70% more light energy for a given output than MH/HPS.
Led is going to heat your tent up but not quite like hps. You should be able to make this work if ambient temp stays between 55 and 70.
I think you will find that 80f or so is better canopy temp to run with leds. They don’t transfer as much heat to leaf surface so best to compensate with aur temps a little to keep growth vigorous.
I used a 600w hps for flower before I switched to led. I have a 3x3 with se3000 now. I have got way more dense buds from the led without all the heat issues.
Led for the win!
LED’s don’t produce as much light as Metal Halide (MH) or HID and are usually about 60-70% as bright as MH or HID (even with the newest LEDs). So a 1000w MH will produce more light than a 1000w LED. However, you will get good growth under a 600w LED and it will be a lot cooler than MH or HID. The tent will trap heat from the LED and a 600w LED will produce a bit of heat and help keep the plants warm in winter.
The main advantage of LED is the plants are unlikely to burn unless they actually touch the light unit and you can have the light unit much closer to the plants without burning them. And LED’s are cheaper to run but if you have a 1000w MH and 1000w LED, they both use 1000watts of power. LEDs also last a lot longer than MH or incandescent globes.
LED’s are almost twice the usable photons that MH/HPS puts out. This is well established. My gen 1 lights are 30% more efficient. New tech is much better still.
For instance I have four plants
Two grew faster than the others.
So up until a week ago the heights of my lights were different heights.
If you look at my tent now.
I had to build boxes to raise my plants to get to same canopy height…
So the big help with two light set up was in vegetation stage…
For flower I’ll raise the plants to make even canopy…
