How to deal with hot summers and extreme cloudy winters?

Lying on the lower reaches of the Kalamazoo River, the Kalamazoo, Michigan climate brings about hot and humid summers. Situated not too far from nearby Lake Michigan, prevailing westerly winds often bring cloudiness and snowfall during the fall and winter months.

Randy’s Greenhouses, located in Kalamzoo, produces potted plants in their 3.2 ha greenhouse operation and combats the hot summers and cold, cloudy winters with the help of Svensson’s open light-diffusing Harmony 5220 O FR and Obscura 10075 FB A + B screens. Owner, JJ Klimp says that one of the operations biggest challenges is energy savings and light management.



“Since installing the Harmony screen we’ve noticed quite a few climate changes, we’re now able to utilize the full energy of the sun during periods of low light (cloudy days and at twilights).” Says Klimp. “Before we would whitewash the entire greenhouse, which resulted in permanent shadeing, even on days when we needed as much light as possible. Now we’re able to decide when exactly we want to decrease the light. On cloudy days we are now receiveing as much light as possible. With our Harmony screen we get better light and more solar gains, which results in humidity reduction and better plant growth. Low light stretches the plants and can delay fowering, while too much light can mean unwanted stress and the need for much more water. The control of the crop is back in our hands. With whitewashing, your hands are really just tied” adds Klimp.

Randy’s Greenhouses is pleased with their selection of the open version Harmony screen, “The open weave shadecloth allows us to keep the screen fully closed during roof venting. This keeps the airflow thru roof vents up, while eliminating the 1-2 foot full sun streak that formerly ran across the length of the crop, making those plants dry faster and have unwanted stress creating on uneven crop,” Klimp says, adding that “my growers don’t have to fight uneven water use, that was formerly caused by the extra light.”
 
Not only is energy a major concern for the operation but some crops require day length control, which is why Randy’s Greenhouses opted for an Aluminum/Black Obscura curtain for heat retention and blackout. Not regretting their screen decision owner JJ says he sees a payback of roughly 2.5 years for the cloth. “Our Obscura curtain speaks for itself when it comes to heat retention. The moment our heaters turn off in the middle of the night in January, you realize the screen was money well spent. We simply don’t have the radiant heat loss that we used to. Once the screen closes, the furnaces begin shutting off within five minutes throughout the facility,” Klimp says.
 
“With our Obscura screen we no longer need to pull fabric by hand to provide the short days our indoor mums require. The system does it for us and is far more reliable. Long gone, are the excuses for heat delay, the screen opens in the middle of the night to release heat and humidity. Also our plants are no longer burned on the edges of crop by direct sunlight thru vents overheating the fabric that used to rest on the plants. It is now overhead and easy."

Having come a long way from what began as a summer job, he now thinks about the operations plans for the future, thinking about how to further grow the company. "Keep moving forward" is a philosophy he lives by.