How Many Watts per Square Foot with Led Grow Lights

How Many Watts per Square Foot with Led Grow Lights

When using LED lighting technology, growers need to calculate the amount of light they need to have in their indoor garden. The amount of light is measured in watts, which is a unit of electricity measurement for power. Using the best LED grow lights provide a very efficient grow room and a large reduction in power costs. Let’s review the wattage requirement per square foot of an indoor garden.

The Watts Requirement Plants Need

An indoor garden should have at least 20 watts of lighting per square foot of growing space. This wattage can be increased up to 50 watts per square foot of growing space.  More light means more growth, but only up to a certain point. Exceeding 50 watts of lighting per square foot of grow space will do more harm than good, so this should be considered around the upper limit.  When the light intensity becomes too strong, plants are not motivated to grow and will experience stunted growth.

When using G8LED grow lights, check the light specifications to find the ideal coverage area. The G8LED 900 Watt Veg/Flower light will cover 24 square feet, which is about 6’ X 4’. This light has an actual power draw of 540Watts, so dividing by 24 gives 22.5 Watts per square foot. Adding in two G8LED Flower Boosters brings the total wattage to 700 Watts and 29 Watts per square foot. Although this is enough light for a 6x4 grow space, you can still add more lighting into this space to get to 50 Watts per square foot.

When planning your indoor growing space, another important consideration is to focus on the photosynthetic photon flux density and the photosynthetic active radiation.

Specifications of LED Grow Lights

When you consider installing grow lights in your indoor garden, the light specifications are something you need to pay attention to. Check the wattage of the light and the power draw.  The wattage is typically in the name of the light. However, the actual power draw of the light is less. For example, the G8LED 900Watt grow light has an actual power draw of 540Watts. The reason the power draw is always less is that the LED chips are never operated at 100% capacity. This is done to avoid thermal breakdown. So even though adding up all the 3Watt LED chips can add up to 900 Watts since each chip is operated at 1.8-2.5Watts only, the total power draw will be the lower amount of 540Watts.

Understanding the Effects of Different Chip Sizes

LEDs come in different chip sizes, from 0.25 watt to 10 watts and even more. When the first LED grow lights were designed, they used very small wattage diodes such as the 0.25-watt chips. The growing strength of the grow light was low and these grow lights were not very effective.  With the LED technology advancing, larger chip sizes were available for indoor grow lights.

G8LED was among the first ones to design grow lights with 3-watt chips. Amongst all the options, the 3-watt chip is a favorable choice for indoor growers, because of the balance of light penetration into the plant canopy and the heat dissipation. As LED chips get larger in size, they have the drawback of giving off more heat, requiring larger cooling systems and being less reliable. The 3-watt chip had the ideal balance of being large enough to penetrate 5-6 feet into the canopy but being small enough to not generate excess heat as larger chip sizes do. Larger chips like the 5-10 Watt diodes are not as stable, require larger power drivers, larger heat sinks and cannot be packed into a dense network of diodes like the 3-watt chips can.

When using LED grow lights, it is always advisable to choose 3-watt chips as the best option even by experienced growers. These are suitable for those plants that grow to about six feet in height. Such lights provide the best penetration and have affordable costs. 

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