Growers share specifics about horticultural LEDs

Cornell GLASE (Greenhouse Lighting and Systems Engineering) Consortium director and 40 Under 40 honoree Erico Mattos led a panel discussion amongst several growers to share their experience with LED-based lighting in different types of growing environments and with varying cultivars. Now, of course there was a lot of time spent on the differences in light spectra and how plants respond — there was plenty of that in the deeper-dive research talks, in fact. But I jotted some other interesting notes from the discussion.

• In introduction, Mattos noted that if all horticultural lighting were fitted as LED right now, a 34% energy reduction would be achieved, but as he cited, 98% of existing greenhouse space is still equipped with high-pressure sodium (HPS) and metal halide.
• Paul Sellew, CEO of Little Leaf Farms (Devens, MA), stated that “produce is a not a subsidized agricultural industry”…So payback to operators is more about operational cost reductions and less loss of produce over time. In Massachusetts, he observed, you mainly need supplemental grow lights during the shorter daylight hours of fall and winter.
• Alex Traven, owner and grower at Peace Tree Farm (Kintnersville, PA), found that LED lighting has a positive impact on the beneficial organisms that the organic operation relies upon to help with biological pest control. The beneficial predator insects Orius insidiosus, for example, were drawn to the previous hot HPS lights in the farm’s greenhouse, which of course obliterated some of those desirable bad-bug killers. But the cooler LED lighting does not harm the bugs and so they continue to help keep pests in check.
• Bob Hoffman, chief scientific officer, Shenandoah Growers (headquartered in Rockingham, VA), described some concerns of the neighboring community about light pollution, noting that the grower installed roll-up blackout curtains that eliminate 95% of light escape. However, “after a few death threats” (wait, seriously??) they changed the lighting regimen and the lights are turned off by 10:00 PM to “be good neighbors.”
• Pablo Costa, operational manager at Van Belle Nursery (Abbotsford, BC, Canada), explained that the nursery’s location and lighting for the most part has not bothered local residents. But once there was a mistaken report of a fire due to the blazing red glow from the lights and the evaporation coming off the greenhouse, and a resident called the fire station. The nursery has also changed its lighting schedule to appear less disruptive, but they do not currently have blackout curtains installed.

I found the directed questions to the panelists to provoke excellent discussion and revealed the differences in operations with varying cultivars and growing priorities; however, there was plenty of applicable insight for all growers — and the technology providers who are looking to supply them. Hit up the archived event for this panel and more.

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