By Thomas Ford
As the growing season comes to an end, growers should consider cleaning and sanitizing their greenhouses or high tunnels before starting next year’s production cycle.
Most structures have purlins, cross braces, and other horizontal surfaces that can accumulate debris or dust that could drop down onto produce during the production cycle. Before cleaning the structure, all equipment should be removed to prevent it from becoming contaminated with the dust/debris accumulated over the past growing season. A power washer is often the best tool for this job, and growers can deploy a stream of water to remove a year’s worth of debris from surfaces in the high tunnel or greenhouse. A grower should use the power washer and then allow everything in the tunnel or greenhouse to dry out before bringing any equipment back into the structure.
Prior to cleaning a greenhouse or high tunnel, the grower should remove all weeds and crop debris from the structure. Weeds and crop debris can harbor an array of pests and diseases that could infest or infect next season’s crop. Drip lines, Bato buckets, hoses, clips, etc. should be removed, cleaned, and sanitized before their reintroduction back into the production area.
If a greenhouse or high tunnel floor is covered with ground cloth or a spun-bound weed barrier, the grower should sweep and pick-up any soil and organic debris accumulated on the ground cloth from the previous growing season. By removing all organic waste from the ground cloth, a grower can ensure that disinfectant products will work without any product efficacy loss.
Disinfectants labeled for use in greenhouses and high tunnels each have unique properties that can impact their overall efficacy when mixed with hard water. Hydrogen dioxide-based products are frequently used by growers looking to disinfect a high tunnel structure or greenhouse because of their ease of use and their reliability as capable disinfectants. Hydrogen dioxide products can cause eye injury, so growers’ protective eyewear should be worn if specified by the product label.
Most disinfectants work more efficiently if they are mixed in warm water (68 to 70°F). Applications should be made to dry surfaces in the early evening in a warm greenhouse or high tunnel for best results. In general, disinfectants require less contact time to kill pathogens on surfaces when temperatures are warmer and more contact time to kill pathogens on surfaces when the temperatures are cooler. Disinfectants should always be mixed according to the product label for best results. Sanitizing solutions that are mixed too strong may damage the object’s surface that you are trying to sanitize. If the disinfectant’s concentration in the solution is too weak, it may not disinfect the surface properly, leading to disease.
Source : psu.edu