The winter months can always be a challenge for floriculture producers. But have you found this winter to be unpredictably dark? Has this affected your crop? Read on to see if this year is unusual or part of a trend and how this may influence your production decisions (and energy costs) in years to come.
Was this year really darker?
The image below, created by climatologist Brian Brettschneider shows which areas of North America were above, near, or below normal solar radiation. Each “tercile,” or category, represents which third of the 1991-2020 data this winter falls within.
As you can see, areas shown in grey, including southern Ontario, received less solar energy than average this season.
Understanding Light Measurements
To determine how lower-than-average light levels will affect your crop, we need to first talk about the importance of Daily Light Integral (DLI), or the total amount of photosynthetic active radiation (PAR) delivered to plants over a 24-hour photoperiod.
Other units for measuring light, such as foot candles or lux, are limiting because they only provide a single instantaneous reading. Natural light levels change throughout the day, and a single measurement doesn’t accurately represent the total amount of light plants get.
In contrast, DLI readings represent the number of light photons that accumulate in a square meter throughout the day (moles per m2 per day) and leads to more accurate recommendations to growers in terms of plant production needs or supplemental lighting use.
Read more at onfloriculture.com