How Many Plants Can Go Under 600w LED?

by Liam | Last Updated: July 27, 2020

Wodnering how many plants can go under 600w LED? We have you covered.

In this article we will answer:

  • What is a 600w LED light?
  • Why are they used to grow cannabis?
  • How many plants can go under a 600w LED light?
  • How much electricity does a 600w LED light use? 

When setting up a grow room or tent, knowing which lighting set-up is best for you will depend on a few factors. 

If you are a beginner grower, you may be thinking that lighting systems are expensive and complex.

You also might be wondering how to know which will give off the proper amount of light and heat for the plants. It is very easy to get confused by all the options available.

But the bottom line is that it is a pretty easy answer.

In this article we’ll be discussing how many plants can go under a 600w LED light.

In this particular article we’ll base the information on using a 4ftx4ft tent as the example with each plant having 9-square feet (3ftx3ft area) and in at least a five gallon size container; whether fabric or bucket.

What is a 600w LED light?

An LED light is comprised of multiple light-emitting diodes and has at least one internal fan for cooling and circulation purposes.

LED lights have an array of colored grow lights (red, green and blue); which all contribute to the growth of a plant (both flowering and vegetative stages) and root growth and formation.

The 600w LED (light emitting diode) light is a favorite among cannabis growers due to its high power, reasonable prices and efficient set-up and expense.

Make sure to read the manufacturer’s information when purchasing a 600w LED; as most say 600w on the packaging, but only put out 400w when at full power.

But these are generally good for personal growers; whereas commercial growers tend to use 1000w LED. But there’s no need to compete with the commercial and dispensary growers.

You need to consider the electrical output and costs; which is discussed later.

Why is it used in cannabis growing?

How Many Plants Can Go Under 600w LED

Aside from being the commonly used lighting system, the 600w LED is known for its cheaper purchase and usage prices.

When you start adding one light, then a second or even a third, you will notice quite a jump in your electricity usage; and perhaps your power utility company will as well. 

Another reason so many growers prefer the 600w LED for growing marijuana is that you do not need to replace the T5 or T8 light ballasts.

You also don’t need to worry about damaging any reflectors or hoods, as the 600w LED come as one unit.

Which also means the downside to using this type of lighting system is that you will have to replace the entire unit as the bulbs start to burn-out and lose their strength.

How many plants can go under 600w LED?

How Many Plants Can Go Under 600w LED

Each 600w LED light has a coverage area of 3ftx3ft, and in regards to the height, it will cover between 18-24 inches. So if you have a 4ftx4ft tent that is 16 square feet of grow space; which according to the calculations of 9-square feet per plant, you would only be able to have one plant inside the tent with one light.

But in reality, that’s not how most growers set up their tents.

If you have ever grown marijuana you like to get the most plants possible in a grow tent, but you need to hold back on overcrowding the plants in a tent. 

The plants need room not only to grow out, but they need the light to be able to “hit” all areas. If you have too many plants in too small of a space then you are limiting the plants’ chance to produce a higher yield.

You may even end up with smaller plants, little yields and unhealthy plants.

General wattage guide

Grow Tent SizeWatt NeededNumber Of Plants 
2×2  4 square feet450w1
3×3 9 square feet450w-600w1 to 4
2×4 8 square feet450w-600w1 to 4
4×4 16 square feet600w-1000w1 to 6
8×4 32 square feet600w-1600w1 to 8
8×8 64 square feet600w-3200w1 to 10
10×10 100 square feet600w-5000w1 to 12

If you still want to have more than one plant in a 4ftx4ft grow tent, then add more 600w LED lights.

Some growers will have four plants in this size tent, but they also accommodate the extra plants with more 600w LED lights.

You need to consider for every plant, you need to have one light.

On more lighting set up to consider to make sure all the plants received proper light exposure, even down to the smaller stems and buds, you can set up a pole at each corner of the grow tent and attach a light system to the pole so all the underneath of the plant gets adequate exposure.

Recommended >> Marijuana Seed Sprout Times

What are some recommended 600w LED grow lights?

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How much electricity does a 600w led grow light use?

Calculating the price and usage of a 600w LED light is actually quite simple. This is where knowing what the actual output of the 600w LED light comes in handy.

Most 600w LED lights draw the power between 360w-400w; so knowing the manufacturer’s power draw of watts is important when figuring out how much electricity a 600w LED light will use.

Let’s say the particular light we are using has a power draw of 400w; which means the light consumes 0.40 kilowatts (kW) per hour. You run the light for 18 hours per 24 hour period.

0.40kW X 18 (hours)= 7.20kW

Next you need to know how much you pay per kW hour; which can be found on your power/electricity bill. For this example we’ll use 12.85/kWh (the average across the US is 0.1283kWh)

7.20kWh X 0.1285/kWh = 0.9252 per day

0.9252kWh X 30 (days per month) = $27.56 per month of electricity

So by this figure, you can assume your electric bill will go up approximately $27.56/per 600w LED light used.