Cost v. Benefit of Hoop House Upgrades
A great example of this is with the decision to add or not add a double layer inflation kit. Often, when new hoop house buyers inquire about whether or not to add a double layer, the answer is variable.
When deciding if this upgrade is right for your farm, consider the R value ( a material’s resistance to thermal conduction) of a double layer system. A double layer of greenhouse plastic hovers around 1.6 so the holding power of heat isn’t the silver bullet some farmers are hoping for.
Next, it's important to determine if the cost of a second sheet of greenhouse plastic, a blower, the electricity needed to run the blower, the initial labor to install the double layer and blower, plus the eventual reskinning of the greenhouse film is going to yield the returns needed to justify the cost.
Ask yourself if you are going to add passive heat like solar barrels, adding active heaters that you are feeding gas or wood, growing cold sensitive plants like vine crops, and growing zone considerations like length of available daylight.
If you live in a temperate grow zone and plan to grow cold loving brassicas, you may not even need a second layer. Whereas, the double poly upgrade would be great for those dealing with coastal winds or those wanting to get a head start on starts for spring.
If you plan on growing tomatoes in an unheated hoop house in Minnesota year- round, you will be very disappointed when the temp gets consistently below 65° no matter if you have a second layer or not. It is all part of the checks and balances you need to think about when planning your farm.