How many watts do I need for 6 plants?

A great growing system is composed of the appropriate room size, soil, plant density, relative humidity, the right temperature, proper air circulation, and the perfect cannabis grow light.

No matter if you’re new or you’ve been growing for a long time, figuring out how much light you need can be tricky. You might have heard that wattage will dictate the light’s power.

While this is partly true, wattages do not exactly equate to power output. Although, wattage is one way to establish the light output needed for your plants.

What matters is the amount of usable light reaching per square foot of your growing area.

Find the Area (Square Footage) of Your Canopy

Calculating your lights depends entirely on one section of your marijuana grow tent — the Canopy. The canopy is the area of your grow room that your plants occupy. This is the only area of your grow room or grow tent your grow lights should be focused on (the old method calculates for the entire room, which wastes lots of light).

To do this, simply measure the length and the width of the area you’re going to have your plants in, and multiply them together. Yup, just like we learned when we were little. So why does that matter?

Well, the most reliable way to figure out how much light you need to light your canopy is by using the “Watts per Square Ft.” method. This method says that you should give your canopy 50 to 75 watts per sq. ft.

However, this would still depend on your growing conditions.

You have to determine the size of your grow room, consider PAR and PPFD levels, and identify plant density to secure the correct led wattage for your grow space.

LED Wattage Chart Explanation

The wattages listed below assume you are flowering your plants. If vegging, you might consider reducing your wattage by 50% since vegging plants only require about half the light intensity. As always, it is best practice to follow the manufacturer’s recommendations.

Using the charts

In each chart you will find the following columns:

• ‘# of Plants’ to be grown


• Square footage that the respective number of plants cover


• Recommended LED wattage for the number of plants grown in the respective space

Wattage charts
Assume about 32 watts/sq ft (actual LED wattage) for flowering. Fewer watts might equate to smaller yields while more wattage may lead to larger yields.

Quick Guide (watts per coverage area)
1' x 1': 32 watts (~30 to 40 watts)
2' x 2': 128 watts (~120 to 140 watts)
2' x 4': 256 watts (~240 to 300 watts)
3' x 3': 288 watts (~250 to 300 watts)
4' x 4': 512 watts (~500 to 650 watts)
5' x 5': 800 watts (~700 to 900 watts)
4' x 8': 1024 watts (~900 to 1100 watts)
6' x 6': 1152 watts (~1000 to 1200 watts)

Recommended wattage assuming 1.0 sq ft/plant

Recommended wattage assuming 2.0 sq ft/plant

Decide On Your Light Level In PAR Intensity

Urban gardening has been made more effective by the most accurate measurement for plants, which is the Photosynthetically Active Radiation (PAR).

PAR is the light spectrum that marijuana plants need for photosynthesis.It is a measure of the energy discharged from a light source that is used by plants for photosynthesis and growth.

Therefore, the higher the PAR output of your LED grow light, the more edible light your plants get.

Usually, the PPF is above 1100 µmol/m2/sec or so, which can cover a 4×4 grow area. Nonetheless, the optimal PAR output should still depend on the growth stage of your plants.

There are various rates of growth connected with different levels of power.

If you are a new beginner, you may be use 240W quantum board led grow light, it is enough for you. I want to recommend ECO Farm 240W V3 LM301H Movable Quantum Board to you.

Growing cannabis indoors may need a lot of energy and power consumption. Plants need a light and energy source that can emit the rays similar to the sun.

Planning a good LED lighting system is essential for a healthy marijuana development.

Remember that wattage alone won’t ensure the light output of your LED grow lights. Wattage should give you an idea about how powerful your LED lighting system could be.

It is important you are able to determine the size of your grow place, as well as how many plants you intend to grow per square foot.

The wattage should then help you identify the DLI, PAR, and PPFD levels. In this way, you are able to precisely calculate the light output necessary for your growing requirements.

You can boost this by using light reflectors and luminaires.

Once you secure how to optimize your LED grow light system, watch how you earn a bountiful harvest.