Photosynthetic photon efficacy (PPE) is a complex concept that can play a significant role in managing spectrum and plant growth in different agricultural environments. It has evolved around discussions of PAR and different grow light models and how these different definitions and applications influence plant health, quality and growth.
“The term efficacy applies to ratios within different units. In horticultural lighting, efficacy refers to micromoles of photon output per second, per watt of input power.” – ‘From physics to fixtures to food: current and potential LED efficacy, Nature.
The formula for photon efficacy is defined as ‘The photosynthetic photon efficacy (Kp) is the photosynthetic photon flux divided by input electric power. The unit is micromoles per second per electric watt (μmol × s-1 × We-1), or micromoles per joule (μmol × J-1)’ according to Hortidaily.
What does Photosynthetic photon efficacy (PPE) mean for the grower?
Efficacy is a concept that can help you optimise and transform your grow light investments and your crop yields. To fully realise its value, you need to have a clear understanding of:
- Photosynthetically active radiation (PAR) and how its spectral range influences plant growth and development.
- Photosynthesis and how this process can be manipulated by the intelligent usage of grow lights and wavelength modifications.
- Photosynthetic photon efficacy (PPE) as it applies to PAR and the different types of grow lights available on the market.
Photosynthetic photon efficacy (PPE) is the critical factor for measuring the efficacy of plant lighting and must be considered when investing in any kind of lighting solution.
For example, GPN Mag points out that a 400-W single-ended, high-pressure sodium lamp has a PPE of 0.9 μmol·J – while a double-ended 1, 000-W HPS lamp has a PPE of 1.7 μmol·J– and LED grow lights can vary significantly with some going higher than 2.0 μmol·J.
LED lights are becoming increasingly efficient and their PPE values are becoming increasingly higher which means that you do need to have a clear picture of how these lights will influence crop quality and yield.
In the paper, From physics to fixtures to food: current and potential LED efficacy mentioned earlier, the researchers point out how LED grow lights can be incredibly valuable, they do need to be combined with other factors such as nutrition, temperature, humidity and more to ensure that all the right boxes are ticked.
Collaborate for Photosynthetic photon efficacy (PPE) intelligence
Unpacking all the qualities of Photosynthetic photon efficacy (PPE) and variable scientific factors is immensely valuable to growers, especially when juggling climate, demand and costs. This is where collaboration with organisations that have the expertise and laboratories to assist you in the development of optimal lighting for your crops can become immensely valuable.
Light Science Technologies has developed a laboratory dedicated to developing the right light and growing recipes and for the furthering of plant science. We work with growers to create optimal horticultural lighting that helps them achieve their very specific goals in very unique situations.
We can work with you to not just discover the value of PPE, but how PAR, LED, and wavelengths can be optimised to suit your needs.