Important! For this calculation you want to use actual wattage.
High pressure sodium and metal halide are the easiest type of lighting to figure out (along with CMH below). There are two methods you can use.
How Many Watts Per Square Foot For LED Grow Lights?
Let’s look at an example.
Well it quite a difficult question bro, like I explained I don’t believe in the 2 gram per watt myth unless you have perfection in your grow room and even then I’m unsure if it achievable?? So if you are looking to save on power costs have you thought about a dimmable ballast for your hps?? You could cut the cost by dimming to around 600 watts for veg in a 5 × 5 then upping the power to 750 for flower and try to achieve 1 gram per watt!! It’s quite a saving on power especially if you are running 1000 watts start to finish, if you really want to change to LEDs tho, take a look at the optic range!! Optic 6 optic 8 or optic 8 plus. Check the specs especially the power draw I think the optic 6 pulls around 640 watts which is nice!! The problem with led is the more they pull from the wall the more the light costs?? If money is no problem for you just keep looking untill you find one with a power draw close to what you need
What Size HPS And MH Lights Do I Need?
Say you have a 3×3 grow tent. That makes 9 square feet. At 30 watts per square foot you would thus want 270 watts in total. If you went up to 40 watts per square foot, you would want 360 watts in total.
Those 400W are also giving you a fairly narrow grow light spectrum, so your plants end up not getting the amount of proper light they need.
Let’s take a look at this short day plants-growing myth, and how you can grow indoors with eco-friendly (and wallet-friendly) LED grow lights.
Where the myth that you need 1000W to grow hemp comes from
The simple answer is: it’s not really about wattage.
Yes. Much like a human sunburn, your plants can burn or bleach if you use too much light.
Do you need 1000W to grow indoors? Not with LED Habitats Grow Lights
The main problem with HPS lights (and other high-intensity discharge / HID lights) is that they end up wasting up to 60% of the energy they consume solely on heat output. In other words, if you’re using a 1000W HPS light to grow indoors, only 400W of that energy is being used for plant growth – the other 600W is being wasted, draining money from your pocket.