300w led grow light yield

300W LED Grow Light Yield: Does LED Give You More?

Grow lights are one of the 9 cardinal parameters for growing cannabis plants. Among different types of lights, LEDs have caught everyone’s attention in recent years.

Which naturally leads you to wonder how much can a 300W LED grow light yield?

With a 300W LED light, in an optimal environment, you’ll get around 1g yield for every watt. With a LED light, the ratio can go up to 1.5g per watt. This means you’ll get a total wet yield of around 150g to 450g.

For maximum yield, light is important. But so are other factors. Hence in this article, we’ll discuss the ways to yield from a 300W LED grow light. 


  • With 300W LED grow light, you can get around 73g ± 14g yield from one plant.
  • The light intensity is the most crucial factor for cannabis plants to grow.
  • Other factors such as soil pH, temperature, water, and humidity can heavily affect cannabis plant growth.

300W LED Grow Light Yield: Understanding Efficacy Of LED Light

There are a few things you need to calculate. This will confirm that you’ll get a high yield from using a 300W LED light.

Because nonchalantly using a 300W will bring you no satisfactory yield. Cannabis plants require a lot of light to grow. If you provide them with enough light, they’ll grow fast. 

And if you can ensure an ideal environment with the maximum PPFD possible, the yield can be astonishing.

300W grow light in action
Source: 420 Green Thumb

Now, how do you know the effect of 300W LED light on a cannabis plant? You’ll need to calculate the total micro mols you’re getting in the 12h lighting period.

Take a look at the unit below-

 µmolm2. S

It reads as micro mols per meter squared per second. This formula tells you the number of photons you’re getting in a square meter per second.

How To Find Out The Intensity of The 300W LED Light:

Measuring the intensity of a grow light isn’t possible with bare eyes. You’ll need an instrument to measure the light intensity of your 300W grow light.

The instrument is a quantum sensor. You can use Quantum PAR Meter which is great for any type of plant.

Connect the sensor to your computer. Or you can purchase a hand-held sensor. Hold it under the light and it’ll tell you the intensity. 

How Intense Is a 300W LED Grow Light?

They are very bright so you must not look directly at the lights with bare eyes. The quantum sensor will help you out here. From a distance of about 30cm or 1 foot, the sensor will read around 2200 to 2900 micromol/m^2.s.

How Intense Is a 300W LED Grow Light
Source: Grow Weed Easy

You must measure the intensity of light. This will determine all the other parameters for the high yield of your cannabis plant. 

The intensity of light actually depends on the type of light you’re using, not the wattage. For instance, between 3000K and 3500K lights, 3500K lights are more intense.

Ideal Environment for 300W LED Grow Light Yield

From a study conducted by Pro. Bugbee of Minnesota State University, an ideal environment was created. I used a 300W LED light to observe the yield. 

Here are the measurements for the ideal environment – 

Lighting300W LED Grow Light, 43.2 mol/m^2.d
Room Temperature65-85 F
Root Temperature78-80 F
Co21200 ppm
Humidity 50-70%
Nutrients50% peat, Silica, Dolomite lime 40g/ft.,
Water1 gallon/day
Diluted nutrient in water1.3 milli-siemens per meter.

The measurements of the parameters were strictly determined by the intensity of the grow light.

With this setup, the final dried flower yield was 73g ± 14g from one plant. We made sure the LED light has 16% blue photons. 

If you can get a 2000 PPFD from your light, amp up the other parameters accordingly. Except for the root temperature and room temperature. However, keep in mind that the 2000 PPFD yield won’t be twice 1000 PPFD. 

Because the line for cannabis yield with light intensity is a rather upward-going curve. After a certain point, the yield doesn’t increase as much.

How Many Plants Can a 300W LED Light Grow?

300W LED is best for 2 to 3 plants for maximum yield. If added to another plant, none of the plants will yield as much in total. 

300-watt LED grows lights are optimum in 4×4 or 5×5 closed grow tents with reflective flooring. So, you don’t need to choose between 4×4 and 5×5 grow tents for that purpose.

You can place 2 to 3 plants carefully after ensuring ample airflow and space to grow.

How Far Should a 300-watt LED Light be from Plants?

The distance between the grow light and the plant is crucial depending on the wattage. However, it’s not as important as the other factors. You can be flexible with the distance if you’re careful about the light intensity.

distance between the grow light and the plant

Although you can comfortably maintain a distance of 12 – 18” with a 300-Watt LED grow light. But you have to make sure that the light intensity for the plant is at least 850+ micro mols/m^2.s. 

Otherwise, the yield will be affected. Your plant will not grow big enough buds.

How Does the 300-Watt LED Yield Change Based on Plant Height?

The plant height is rather a secondary concern when you ensure the correct intensity of light. As the measurements are stated in the previous sections, maintain the intensity for each 12-h lighting period. Provide enough nutrients and you’ll have maximized yield from a 300W grow light

I am saying this with confidence because I followed a study. It was conducted by Minnesota State University. The plant stays compact with more blue light protons and grows taller with red light photons. Between blue lights and red lights, red lights are more beneficial for plants.

But the yield stays more or less the same.

300 Watt Led Yield: Concave or Convex Reflector?

If you want to maximize the PPFD, it’s better to use a concave reflector and a reflective floor to maximize the PPFD.

Light reflector in grow tent
Source: Grow Weed Easy

Such a setup will increase the PPFD per square meter. However, you can use a circular 32-inch reflector as well. The results will not change drastically with either of the reflectors.

Can You Combine 3 100W LED Grow Lights?

Yes, you can combine 3 100W lights. In fact, there is no LED light that is 300W. All of them are built with multiple wattages of LED lights combined together. So, connect the 3 lights in a series connection and you’ll be fine.

3-100W LEDs vs 300w LEDs: How Does the Yield Change?

The yield doesn’t change between 3 100W LED lights Vs 1 300W LED light. Because the DLI will be equal in both situations. No matter how you measure the intensity, both setups will be equal to each other.

Frequently Asked Questions (FAQs):

Does LED light yield more than HPS?

LED yields more than HPS light if the yield is calculated as yield per kilowatt-hour. LED lights provide more blue photons whereas HPS provides only 4% blue light photons. And blue light inhibits higher cell expansion. So when you calculate the yield per kilowatt-hour, LED gives you more yield.

How bright is a 300-Watt LED light?

300W LED lights produce about 40,000 lumens. As per PAR, they are about 400 to 700 nm. But for plants, the measurement should be calculated as micromol/m^2.s. normal household or office LED lights are about 7 micromol/m^2.s. But a LED grow light measures up to 3000 micromol/m^2.s. 

Does LED grow lights cost less to run?

LED grow lights are about 30% more costly than HID grow lights. They save on heating, cooling, and electricity. As for yield, the blue light photons that increase cell inhibition are 88% more effective than HPS light blue photons. When the yield is calculated with kilowatt-hour, LED yields more.

Ending Note

That’s all you need to know regarding a 300W LED grow light yield. There are many myths floating around about the lighting aspect of growing cannabis. 

I tried to debunk the myths and provide you with more accurate information. Hopefully, you can utilize the information from the article and increase your yield.

Best of luck!

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