With the impending threat of snow and ice accumulation, Dr. Grant Ellington offers ideas for protecting our greenhouse structures. Hopefully, we will miss a lot of the ice, but better to prepare than have an accident. It appears that the probability of getting an accumulation of snow and/or ice over the weekend is increasing significantly. We are rapidly approaching greenhouse transplant production, and this storm could negatively impact greenhouses. It has been several years since we have encountered this type of event, and I wanted to send some reminders in terms of preventative steps and things to consider.

1. Turn the heaters on and keep them going during the event to minimize roof accumulation of any snow or ice. The weight can become excessive with just a few inches of wet snow and fractions of an inch of ice. I would set the heater thermostat to 60 degrees Fahrenheit or higher, if needed, to ensure adequate melting. Hopefully, the greenhouse heaters are working, and the fuel tanks are adequately filled. They may have to run continuously for a couple of day,s and it will get costly in terms of fuel usage, but it is better than replacing a house this close to seeding. Inflation fans should stay on to keep the plastic tight and make it easier for any accumulation to slide off the roof and provide additional insulation. Probably be a good idea to go ahead and get the greenhouse temperature elevated prior to any frozen precipitation. Heaters may have a hard time keeping up with the accumulation if the precipitation rate is excessive, and they wait until the precipitation begins. Continuous monitoring will be important.
2. With a significant ice accumulation event, there could be a lot of widespread power outages. Many growers today have backup generator capacity, but they need to make sure all that equipment is functional, and enough fuel is available to operate a standalone generator or tractor-driven PTO unit for multiple days. The goal is to keep the heaters and inflation fan operating during the event.
3. If a grower does not have backup power and experiences a power outage, it might be safer to remove the plastic or cut it to avoid any significant structural damage to the greenhouse. Structural damage would be more expensive and timely to replace. Otherwise, they will need to manually remove any roof accumulation from the inside of the house, without the inflation fan operating. This will be more difficult to complete due to the sagging plastic between the roof supports and will require continuous monitoring.