Friday, January 29, 2021

Greenhouse Lighting: Are Your Tired Grow Lights Letting Your Crop Down?

Researchers and growers alike recognize a lighting truth: A 1% increase in light levels returns a 1% increase in yield. Of course, this only applies when the light level is below the crop’s photosynthetic saturation point. The point at which light limits yield will vary with several factors, including the crop species, crop fertility, and temperature. 

Horticulturalists around the world make cost-effective decisions about lighting every day. In some places for some crops, crop quality during low-light times of the year is maintained by growing cooler and slowing the crop cycle. In other areas, supplemental lighting is added to keep consistent production and quality week after week. For indoor and warehouse cultivation, a stable environment is maintained year-round by sole-source lighting.

Greenhouse lighting plan

Sole-source lighting can be planned to provide consistent, uniform delivery of photons over the crop to provide a consistent harvest. This kind of lighting setup can be achieved with high-pressure sodium (HPRS), metal-halide (MH), or LED lighting technologies.

What happens when HPS and MH bulbs age? 

HPS and MH bulbs generally have a 10,000-hour life. You should expect their output to drop by 10% over this time. That means that a lighting plan initially providing adequate light to meet your yield goals will give you 10% less yield when bulbs hit their recommended end of life. Think about that. What does 10% less yield mean to your bottom line?

While we are thinking about this, what do 10,000 hours mean for a typical indoor production facility?

    • 12 hours/day: 2.25 years

    • 16 hours/day: 1.75 years

    • 18 hours/day: 1.5 years 

The easiest fix for diminishing photon output is to set a maintenance plan to replace your HPS and MH bulbs on a cycle that aligns with your use and sensitivity to decreasing yields. As we come to the end of the year, many operations can achieve tax benefits on Capex equipment purchases delivered prior to January 1, making this is a perfect time to replace your bulbs. 

Let us help you maintain your yields, so you continue to meet your production goals. Ask your Griffin salesperson about options for single end and dead-end HPS and MH replacement bulbs from leading manufacturers, including ParSource, Ushio, Hortilux, and Philips.


Griffin also offers a wide assortment of LED lighting technology. We can help you through the transition from HPS/MH to LED, both on the equipment and culture sides of the equation. 



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