Understanding the concept of LED beam angles can be daunting, especially for new growers who are navigating through the terminology while selecting their lighting solutions. The beam angle of an LED light refers to the angle at which light is emitted from the LED emitters. It is measured in degrees, typically ranging from 90 to 120 degrees, although certain COB LEDs can have beam angles as wide as 180 degrees.
While some may believe that a larger beam angle is always better, particularly for larger grow spaces, it is essential to consider the trade-offs. A wider beam angle means that the light from the emitters is spread over a larger surface area, resulting in lower light concentration overall.
Choosing the appropriate beam angle requires striking a delicate balance, considering factors such as ceiling height and the size of your grow environment.
Methods of Measuring Beam Angle
Beam angles can be measured in two ways. The first method involves measuring the angle at which the light’s intensity reaches 10% of its peak intensity on either side of the light’s center. However, this approach is less common.
The more prevalent method is known as “full-width, half-max” (FWHM), which measures the angle at which the light has 50% peak intensity on either side of the light’s center. For example, if a light’s intensity reaches 40% at an angle of 45 degrees, the beam angle would be measured as 90 degrees using the FWHM method.
Transitioning from High-Pressure Sodium (HPS) lights to LED lights can add complexity to understanding beam angles. HPS lights have a fixed 360-degree beam angle, contributing to their energy inefficiency as they lack control over the light’s direction, leading to wasteful energy expenditure.
LED lights, on the other hand, come with reflectors that control the angle of the diode. There are two main types of beam angles: wide and narrow.
Wide angles can range from 90 to 180 degrees, with 120 degrees being the most common and narrow angles being 90 degrees or less, usually as low as 60 degrees.
Determining the Ideal Beam Angle
Light concentration plays a critical role in plant health, especially when using LED lighting. LED fixtures offer the advantage of adjusting spectrum settings to achieve better control over the final yield. Diluted light concentration reduces this control. While a wide beam angle disperses light more broadly, it provides less intense light directly beneath the LED.
Most growers tend to favor narrower beam angles, while wider angles are typically used in large retail stores and shopping malls to illuminate expansive spaces.
There is no exact formula for determining the ideal beam angle, as it depends on several factors that affect effective plant growth.
Ceiling Height Considerations
The height of your ceiling plays a significant role in determining the appropriate beam angle. The farther your lights are from your plants, the lower the light intensity. Therefore, higher ceilings require narrower beam angles to compensate for the increased distance. On average, ceiling heights range from approximately 8 to 9 feet. In this case, a beam angle between 60 and 90 degrees should be sufficient to ensure adequate light coverage.
For larger commercial operations with exceptionally high ceilings, a beam angle of 45 degrees or less is necessary. Additionally, more light fixtures may be required to ensure that light reaches all corners of the grow space effectively.
Size of the Growing Space
Although narrower beam angles are typically recommended for optimal plant growth, in smaller spaces, wider angles can often suffice. This can help save costs by requiring fewer fixtures without compromising the health of your plants.
Hobby growers who operate within a single room or tent, with dimensions of around 4′ by 4′ or 5′ by 5′ square feet, can generally achieve satisfactory results with a 120-degree beam angle. In such cases, a single fixture may be sufficient, provided that the ceiling height does not exceed nine inches. Since the light is spread across a small space, the decrease in light intensity will be minimal.
Highly Reflective Walls
In the context of light intensity, the inverse square law suggests that as lights are positioned higher, the intensity decreases. However, this principle does not hold true if your grow space has highly reflective walls. With walls that exhibit high reflectivity (over 95%), light loss is minimal when the lights are raised higher, such as in grow tents. In fact, raising the lights in the presence of highly reflective walls can enhance light uniformity and penetration into the canopy.
The Bottom Line on LED Beam Angles
Although beam angles may appear complex initially, they become more understandable once you grasp the fundamentals of LED lighting. For larger commercial operations, a string of narrow-angled LED lights is generally recommended. However, hobby growers working in smaller spaces can achieve favorable outcomes with fewer lights and wider beam angles. Grow operations with highly reflective walls can leverage very wide beam angles while still obtaining excellent results.
While most growers find success with beam angles in the range of 60 to 90 degrees, it’s essential to consider your specific grow space and factors like size and ceiling height before finalizing a beam angle range. By carefully assessing these elements, you can optimize light distribution and create an environment conducive to healthy plant growth.
For more information or assistance in selecting the ideal beam angle for your grow lights, feel free to reach out to us at Recolux Lighting.
