Spring is a very busy time of year at Midwest Groundcovers, as we begin uncovering the growing shelters that house and protect our plants over the winter. We utilize poly sheeting in all five of our nursery locations as covering for our nearly 3,000 growing shelters and roofing for our greenhouses. The process begins each year in October, when our crews begin covering the plants in our growing shelters with 4 or 6 mil poly. Each shelter can house up to 2,500 #1 or 430 #5 containers (spaced). Using pneumatic staple and nail guns, a crew of 10-12 workers can cover up to 100 shelters per day! Less hardy plant varieties—such as roses and Hydrangea macrophylla varieties—require a double layer of poly covering (with insulating air between them) and Microfoam thermal blankets for added protection. In mid-October, the plants are fertilized with potassium nitrate to help prepare the roots for winter.
It’s important that the plants have adequate moisture until the containers freeze and the plants go dormant, so our growers continue to irrigate the plants until late-November. This requires frequent draining down and refilling of our extensive irrigation systems, to prevent the pipes from freezing and breaking. Throughout the winter months, our growers monitor the weather and scout the houses daily to check temperature and humidity levels. While we all may enjoy a sunny, 40-degree winter day, it can become a real problem for the plants, since the growing shelters can heat up to 70 degrees! This temperature fluctuation is a bigger threat to the plants than the severely cold winter temperatures. To help modulate the growing shelter temperature on warm days, our growers will roll back the poly sheeting to open the doorway ends of the growing shelters. Then when the temperatures drop, they roll up the poly sheeting to seal the shelter back up. This is all done manually, so it is very labor intensive.
Winter pruning of our hardier plant liners will begin in January and wrap up in March with the tender species. During a normal winter, watering will resume in February with the refilling, draining down, and refilling process of the irrigation systems. Starting in late March, we begin uncovering the junipers and other hardy evergreens, and by mid-April most plants are uncovered. However, the roses and Hydrangea macrophylla will remain under cover until early May to protect them from late spring snow or frost. During the uncovering process, we use our own custom-fabricated hydraulic poly roller mounted on a skid steer to roll up the poly sheeting into tight bundles. The bundles are then stored safely under cover until the following fall when they are re-distributed, unrolled and re-installed on our growing shelters.
While some growers replace their poly covering every year, we have been able to extend the use of our growing shelter coverings for up to 4 years! We are aware of the current worldwide crisis in plastic recycling, and are committed to using sustainable practices whenever possible. Which is why, once the poly has deteriorated and can no longer be re-used, we then recycle it. We have established a relationship with a recycler in the Midwest area that accepts agricultural poly and recycles it into grocery or garbage bags. Last season, one of our growers, Tyler Perkins, organized a collection of poly sheeting from our Illinois nursery locations and prepped it for the recycler. This effort resulted in recycling three truckloads of poly sheeting totaling 75,000 pounds. As growers for the Midwest region, we are committed to continue to look for ways to conserve our Earth’s resources and beautify and protect our environment.