Too many variables to know. Weather - some nights it will be plenty of insulation with no added heat, other nights you may have to double the cover on the low tunnel or up the heat. Some nights it may even be too hot in there. It's the fickle nature of early spring weather. We have the same issues in the greenhouses.

As long as you can closely monitor the temps and adjust as needed you can make it work but it takes real close monitoring, lots of thermometers, and often more than 1 source of heat.

Dave.