How far should led grow lights be from plants

Key Takeaways:

  • A well-designed lighting system is crucial for indoor farming. 
  • The distance between grow lights and plants depends on the type of lighting used and the species being grown. 
  • Most indoor farmers are switching to LED lighting over HID and fluorescent T5. 
  • Understanding technical terms such as PAR, PPF, PPFD, and micromoles is important for measuring light and determining grow light distance. 
  • LED lights have advantages over traditional lights such as longer lifespan, lower maintenance, and ability to generate the entire spectrum of visible light colors.

The lights should initially be placed 12–24 inches above the tops of the plants, and this distance can be modified as needed according to the plant’s requirements and the light intensity.

 

How to measure the light that reaches your plants

The amount of light that your plants receive can be determined in a few different ways:

 

Light meters

Light meters are portable instruments for gauging the brightness of an area. They provide a more precise measurement of light intensity, usually in foot-candles (fc) or lux (lx) units.

 

PAR meters

PAR meters, short for “photosynthetically active radiation,” are devices that gauge the intensity of a narrow spectrum of light necessary for photosynthesis in plants. The light that plants actually use can be more accurately measured with a PAR meter, which is optimized for measuring light in the 400-700 nm wavelength range.

 

Camera

Take a picture of your plants while they are under the light with your digital camera, and then use an app to determine how much light they are receiving. This technique is useful for keeping tabs on fluctuations in light levels over time and can provide you with a rough estimate.

 

Visual Inspection

By looking at the plants, you can tell if they are getting enough light with this method. Pale leaves, elongated stems, and slow development are all signs of a lack of light.

Other factors, such as temperature, humidity, and nutrients, also play a role in plant growth in addition to light intensity. Because light levels differ at different points on a leaf, it’s crucial to keep an eye on things from that vantage point as well.

 

How far should LED Grow lights be from seedling?

Seedlings are also sensitive to high-intensity light, and exposing them to too much light too soon can causes stress and damage. It’s important to start with a lower-intensity light and gradually increase the distance as the seedlings grow and become more resilient.

Here are some recommendations for different wattages of LED grow lights and seedling stage:

  • 200W LED grow lights: up to 18 inches 
  • 300W LED grow lights: up to 24 inches 
  • 400W LED grow lights: up to27 inches 
  • 500W LED grow lights: up to 30 inches 
  • 600W LED grow lights: up to 36 inches 
  • 800W LED grow lights: up to 40 inches 
  • 1000W LED grow lights: up to 48 inches

 

How far should LED Grow lights be from vegetative?

In the vegetative stage of plant growth, the main goal is for the plant to grow healthy and strong leaves and stems. The light spectrum needed during this stage is typically in the blue range, with peak wavelengths around 450-470 nm. This is because blue light promotes healthy vegetative growth and the development of strong stems and leaves. However, it is also important to provide some red light (around 660 nm) as it helps with the photosynthesis and energy production of the plant.

Here are some recommendations for different wattages of LED grow lights and vegetative stage:

  • 200W LED grow lights: 12-24 inches 
  • 300W LED grow lights: 18-24 inches 
  • 400W LED grow lights: 24-36 inches 
  • 500W LED grow lights: 24-36 inches 
  • 600W LED grow lights: 30-40 inches 
  • 800W LED grow lights: 36-48 inches 
  • 1000W LED grow lights: 36-48 inches

 

How far should LED Grow lights be from flowering?

During the flowering stage, plants need a high intensity of light to support the growth of blooms and flowers. The intensity of light needed for this stage is typically higher than that of the vegetative stage, as the plants are using the energy from the light to produce reproductive structures. Additionally, the wavelength of light that is most effective for promoting flowering is in the red spectrum. It’s important to provide the plants with the right intensity and spectrum of light to ensure optimal growth and blooming.

Here are some recommendations for different wattages of LED grow lights and flowering stage:

  • 200W LED grow lights: 8-17 inches 
  • 300W LED grow lights: 10-20 inches 
  • 400W LED grow lights: 14-21 inches 
  • 500W LED grow lights: 20-27 inches 
  • 600W LED grow lights: 15-30 inches 
  • 800W LED grow lights: 20-34 inches 
  • 1000W LED grow lights: 36-48 inches

 

Where Should Grow Lights Be Located for optimal result?

Grow lights should be located as close as possible to the plants without burning them. The distance will depend on the intensity of the light and the type of plant you are growing. A general rule of thumb is to start with the light about 12-18 inches away from the top of the plant and adjust as needed. It’s also important to ensure that the light is evenly distributed over the entire plant canopy and that the plants are rotated regularly to ensure even growth on all sides.