One of my greenhouses, although situated under trees, has been shaded all summer with green net.  It is now time to remove this to give my plants a boost of light before the darker winter days.  My other greenhouse gets plenty of south facing light and I will leave the shading a little longer.

The picnic season is almost over but I have a really good use for those  frozen ice packs used to keep picnics cool.

In my shady greenhouse I grow orchids from cloud forests such as Masdevallias, Pleurothallis and Restrepias.  In winter I do not want the temperature going below 12 degrees celsius.  The greenhouse is bubble wrapped all year round.  In winter it acts as insulation to keep the heat in and in summer, aided by shading,  it helps to keep the heat out.  It will not be many weeks until I need to use my greenhouse heater to keep my plants cosy at night.  How do I know it is working?

My greenhouse heater has an external thermostat to regulate heat the appliance puts out.  Today it was 20 degrees in my greenhouse, the  heater was not going to switch on to prove it was working.

By placing the censor between the ice packs the heat soon began to fall and on came the heating at 12 degrees.  I now know it is working and will turn on with the cooler nights.

I did the same test in my other greenhouse where I grow orchids that can tolerate a lower temperature, 6 degrees celsius.  I grow Coelogynes, Cymbidiums and Dendrobiums in this one.  The heater worked perfectly.

At school heating for the greenhouses comes from a gas boiler.  Unfortunately it often breaks down and then we use our back up thermostatically controlled fan heaters.  This is just enough heat to keep the cold at bay until the boiler is fixed.