At Abbottsford, British Columbia-based Van Belle Nursery, Pablo Costa controls Philips Lighting-brand LED lights through sensors. As operations manager for the nursery’s Colour-Retail Ready Division, Costa grows hydrangeas under the LEDs in one, one-acre zone — out of 10 acres of total greenhouse space covered with double poly. He also performs trials with the LEDs on various annuals, perennials and succulents.
Below are five benefits Costa has seen from using the LEDs:
1. Extending DLI. Daily light integral (DLI) is the amount of light plants receive in a single day. In the middle of winter, the DLI at Van Belle is about 2 mols per day, which equals about eight hours of natural sunlight. Measuring Van Belle’s DLI in µmol·m-2·d-1 and hours of light using sensors, Costa has been able to quantify that, using Philips LEDs, the nursery receives more than 12 mols per day and 12 hours of continuous light per day.
2. Saving energy costs. Although they often have a higher initial investment, LEDs are lower-maintenance, last longer and do not give off the same amount of heat as high-pressure sodium (HPS) lights, Costa says. He says that calculating costs is always important. “Calculate your ROI — return on investment — and what money you have [at your disposal] to spend to invest first,” he says. In general, Costa predicts the ROI for LEDs will shorten in the coming years.
3. Improving plant development and growth. Under less-than-ideal lighting conditions — such as the natural conditions at Van Belle Nursery in the winter — plants do not always fully develop. But plants need light to grow to their full potential, Costa says, and this is where LEDs come in. “If you have more [light], you are going to have better performance,” he says.
4. Making plants more compact. Plants stretch to reach the light if there isn’t enough of it, but by using LED lights, Costa has found that his plants don’t stretch as much and are more compact. “At the end, we use less PGR, and we have the flowering on time,” he says. (Editor’s note: To learn more about how LEDs can make plants more compact, read about Dr. Ricardo Hernandez’s research at NCSU in “Lighting the Future”)
5. Strengthening plant color. Plants with red hues that Costa grows under LEDs, including many of the hydrangeas and annuals such as coleus, have stronger colors than those that he grows without LEDs, he says. “Also, the green color of the leaves is greener, so at some point, you need less spraying of micronutrients that we usually do, especially for the hydrangeas,” he says. “When you have [plants] under the lights, the color of the leaves is a little bit greener than the other ones, which are paler.”