Providing optimal light level for plant growth

Each crop has an optimal light level that maximizes growth. Tom Dudek, Mich. St. Univ. Extension senior district extension horticulture and marketing educator, said growers need to know about the daily light integral (DLI) and how it impacts growth. Increasing the DLI can: increase number of roots, shoots and flowers; reduce time to flower and increase flower size. These changes can usually be accomplished by using supplemental light during low DLI periods of winter.
Roberto Lopez and Ariana Torres at Purdue University have prepared a publication “Measuring Daily Light Integral in a Greenhouse” that provides information on DLI, how to measure it, along with recommendations on the optimum DLI for 70 common greenhouse crops. A Spanish version is also available.

Pictured: Providing the optimum daily light integral for plants can increase roots, shoots and flowers and hasten flowering.