What Watt Grow Light Do I Need

As a rule of thumb, aim for 20 to 40 watts per square foot. Divide the wattage of your bulb by 20 (such as 400 watts divided by 20 = 20), and then divide the wattage of your bulb by 40 (400 divided by 40 = 10).

What wattage should my grow lights be?

As a rule of thumb, aim for 20 to 40 watts per square foot. Divide the wattage of your bulb by 20 (such as 400 watts divided by 20 = 20), and then divide the wattage of your bulb by 40 (400 divided by 40 = 10).

How much LED grow light do I need?

Standard advice says you should aim for 32-50 watts per square foot of grow space. More like 25 watts if your grow space is a dedicated veg tent. So if you were working with a 3′ x 3′ space, you’d theoretically want an LED light with a power draw somewhere between 225 watts (vegetative) and 450 watts (flowering).