If you have plants inside your Polytunnel or Glasshouse in the winter months there are accessories available to help keep the cold at bay and protect from frost damage. The crop protection fleece will work as a duvet for plants and we have a range of thermostatically controlled heaters that can be used. The heaters will have the advantage of making snow melt before it can build up, helping to protect your Greenhouse or Polytunnel against structural damage.
On milder days it would do no harm to open the doors for a few hours to ventilate your Polytunnel . Frost occurs when air stands still. In Q gardens last year the plants inside unheated Polytunnels with open doors were affected less by frost than in the unheated Polytunnels with closed doors.