PROTECTING tender plants in the depths of winter can either cost you a small fortune in heating bills or, if you make a few adaptations, the cost can be minimal and you won’t fall off your chair when you check the electricity bill in the New Year, writes TOM ATTWOOD. I’m speaking from experience here and have learnt the hard way. When I was working on a large garden project in the lakes 10 years ago a substantial greenhouse was included in the rebuild and this spacious, lofty structure was to serve many functions which included the overwintering of tender plants. I purchased a semi-professional electric fan heater, suspended from the steel bars above and without any additional insulation switched the fan on. A built-in thermostat would regulate the temperature and (I thought) would do the bare minimum necessary to keep the frosts at bay. An impressively cold period hit for several weeks and in early spring a somewhat ashen faced manager said to me, we have a £500 bill for the heating in the greenhouse, is that correct? The first mistake I made was to attempt to heat the entire structure and secondly, not to add any additional insulation against the glass. Today I try to heat the absolute minimum space and create a bubble-wrap ‘tent’ within one of our greenhouses here at the nursery. Even in a small space a great number of plants will fit as the containers they are in can be creatively stacked (with the addition of basic shelves you can maximise the vertical space as well as that on the ground) recycled wooden slats can be fixed together to make a frame onto which the bubble wrap can be stapled or pinned. The heat source I use are two water resistant electric bar heaters that have built in thermostats and use the equivalent power as two lightbulbs when on. Spaced equally on the floor they provide consistent warmth. They only need to be on when night temperatures of three degrees or less are forecast and can remain switched off when not needed.

Next week: protecting fruit trees from winter moth damage