PAR light measurement

Finding the right balance between light and temperature

Controlling the balance between the production and consumption of assimilates helps the crop grow and produce optimally. One way to support this balance is by matching temperature to the available light. To do this effectively, you need a clear picture of the amount of light the crop receives.

Assuming that CO₂ and water availability are sufficient, the amount of light influences how many sugars the plant can produce through photosynthesis. At the same time, growth, development and respiration are strongly influenced by temperature. The higher the temperature, the faster these processes generally take place and the more assimilates the plant consumes.

For good control, it is therefore important to know how much PAR (Photosynthetically Active Radiation) the crop receives, both at a specific moment and throughout the day.

Measure what the plant can use

PAR is the part of the light spectrum that plants can use for photosynthesis. Measuring PAR inside the greenhouse provides insight into the amount of growth light that actually reaches the crop.

This information helps growers better align the 24-hour temperature with the available light. Within Plant Empowerment, this relationship is expressed through the RTR: Ratio Temperature to Radiation.

There should be a balance between the amount of PAR light the plant receives, the total light sum and the 24-hour temperature. Accurate PAR measurements provide the information needed to make better decisions about this balance and choose a more appropriate growing strategy.

Want to learn more about artificial lighting?

Want to learn more about PAR light, RTR and how to measure light in your greenhouse? Explore our four-part e-book How Artificial Lighting Can Optimize Efficiency for in-depth knowledge and practical examples.