Cary Mitchell, from left, and Celina Gomez harvest tomatoes grown around red and blue LED lights, which use far less energy than traditional high-pressure sodium lamps in greenhouses. (Purdue Agricultural Communication photo/Tom Campbell)
We’ve touched upon innovative uses of LEDs and research into the benefits of LEDs with cows and bees, but there’s news that LED lighting can cost effectively improve the growth of greenhouse tomatoes and a start-up is working on affordable LED lighting to help small farms increase egg production in chickens.
According to the USDA, the U.S. is one of the world’s leading producers of tomatoes, second only to China. Fresh and processed tomatoes account for more than $2 billion annually. Fresh-market tomatoes (not the ones that are processed) are produced in every state, with commercial-scale production in about 20 States led by California, Florida, Ohio, Virginia, Georgia, and Tennessee. The supply is seasonal depending on the weather.
Many producers grow tomatoes in greenhouses off-season, traditionally lit by very warm high-pressure sodium lamps. Researchers at Purdue University are looking into whether growing tomatoes under LED lights in the winter can significantly reduce greenhouse energy costs without sacrificing yield.
Perdue horticulture professor Cary Mitchell, interviewed in a Purdue newspaper, said the average tomato is shipped about 1,500 miles from warmer climates where they’re grown to cooler climates that cannot produce the fruit cost-effectively in the winter. According to Mitchell, the journey is costly because tomatoes are picked green and ripen during shipping, decreasing quality and flavor. In addition, the shipping distance adds cost and adds to the industry’s carbon footprint.
Mitchell and doctoral student Celina Gómez experimented with light-emitting diodes, which are cooler and require far less energy than traditional high-pressure sodium lamps used in greenhouses. According to the article, the researchers received the same yield – size and number of fruit – with high-pressure sodium lamps and LED towers, but the LEDs used about 25 percent of the energy of traditional lamps.
The goal of the research is to reduce costs to the point where local growers could compete with the tomatoes that are shipped from far-away places. Local tomatoes could be harvested vine ripe, would taste better and would boost local economies.
“The United States still imports one-third of its tomatoes from Mexico and Canada, as well as other countries,” Mitchell said in an interview with Purdue Agriculture News. “This technology could allow U.S. growers to create local jobs that shrink carbon footprints and produce better-tasting tomatoes.”
Finally, a small group of recent grads from of the University of California, Davis, formed start-up Henlight to develop a solar powered LED light for small scale egg farmers to light chicken enclosures. Scientific evidence shows that the amount of eggs a chicken will lay is strongly correlated to the amount of sunlight received per day.
Large-scale egg producers already use light to artificially boost egg production. For example, the spring and summer typically provides between 12-16 hours of sunlight per day giving poultry the necessary amount of light to reproduce (produce eggs). In the fall, the amount of daylight decreases along with egg production. This reduces a farmer’s income and access to nutrition from eggs. Henlight could bring this capability at low cost to small farms around the world . Henlight’s founders received a $10,000 prize as start-up investment to launch the product.
For Further Reading
Clearlysapphire.com, Benefits of LED Lighting for Cows and Bees, http://blog.clearlysapphire.com/?p=472
NPR Berlin, Increasing Egg Production On Small Farms: A Solution To The International Food Crisis?, http://nprberlin.de/post/increasing-egg-production-small-farms-solution-international-food-crisis
Purdue University, Agriculture News, LEDs reduce costs for greenhouse tomato growers, study shows, http://www.purdue.edu/newsroom/releases/2013/Q2/leds-reduce-costs-for-greenhouse-tomato-growers,-study-shows.html