The Daily Light Integral
What DLI is and why it matters
The quality of plant growth is, in terms of light, dependent of one crucial metric: The daily light integral (DLI). It describes the amount of light a plant receives over the period of one single day and its high importance for plant growth is well researched.
What It Is
The principle of the DLI is relatively simple: It describes the amount of light a plant is receiving over a single day.
In an outdoor setting, this varies strongly by weather, location, season, and the placement of the plant. In an indoor setting with artificial lighting it is a lot less complex with just the intensity of the light and the amount of time it is turned on factoring in.
Effects on Plants
DLI levels are strongly related to the growth rate of a plant and the productivity of a crop. Each type of plant has its own unique requirement to light and therefore other levels of optimal DLI.
Providing the plant with more DLI than it optimally needs does not lead to additional growth. Furthermore, it might even be harmful to the plant in cases of increased temperature due to the strong light.
Plants thrive to their full potential with the optimal amount of light. By knowing the optimal DLI for a plant, the lighting setup can be adjusted to maximize the growth rate and yield for every individual plant. Simply know your plant’s DLI, measure your current DLI with Photone and adjust accordingly.
In an indoor garden, a huge amount of energy goes to lighting and climate control. By adjusting the lighting setup to the maximum DLI of the plant, every increase in light intensity or duration is a waste and can therefore be saved.
Your Plant’s DLI
DLI levels are well researched for many types of plants and can easily be found online. Flowering plants such as Cannabis (30 - 45), peppers (30-40), or tomatoes (20 - 30) require a high DLI. Some vegetables such as Zucchini (20-25), Broccoli (15-35), or lettuce (13-18) thrive with a lot of light as well. Most common herbs grow optimally with a DLI of around 10 to 12 and most shade plants like a rather low DLI of 6 to 10.