Daily Light Integral (DLI) is the amount of PAR (Photosynthetically Active Radiation) that is received by your plants over a 24-hour period. The natural light available will depend on your greenhouse location and the DLI will typically change with the seasons, as the natural day lengths (photoperiods) and light intensities (PPFDs) can vary quite drastically over the course of a year. In many locations, the summer provides long days and high light intensities, whereas in the winter, both the light intensities and the day lengths are lower, resulting in a significant decrease in the DLI. The average monthly DLI for the United States and the Nordic and Baltic countries is shown below. 

A research review and high resultion map of the Daily light integral os the United States
Graph showing Daily light integral through the months of the year

The DLI requirements vary from crop to crop, but the general rule of thumb is that if these requirements are not met, growth and development will be delayed. By adding supplemental light into your greenhouse, you can increase the light levels and thereby increase the DLI, which is beneficial during these low light periods. Navigating control and gaining a comprehensive understanding of DLI can be challenging. Therefore, a smart control system integrated with sensors, such as helioCORE, can help streamline this process. The system controls the use of supplementary light to achieve the target Daily Light Integral (DLI). But it also allows you to see graphs of the DLI, showing how much natural light and lamp light has been used to achieve the target DLI. By allowing the wireless sensors to track the light at crop level throughout the year, you can connect your most successful growth and DLI.

Graph showing PPFD

Pic from helioCORE 2.0

Curious about delving deeper into the importance of DLI and the perks associated with implementing a dynamic lighting solution to optimize your crop yields?

Download our free eBook
Understanding the impact of Daily Light Integral
and learn more today!


Source: Enabling Year-Round Cultivation in the Nordics-Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral. Marco Hernandez Velasco 2021 

Related content

Get in touch with us!

From custom light planning, to tailored quotes, and everything in between,
our team of horticulture experts are always ready to assist.