With the warm April sun starting to have an impact it is time to shade your orchid house if like me you grow cool tropical species in a greenhouse at home.
Inside, these are all species native to the cool mountains of Central and South America, or the Himalayas so the temperature ranges from a minimum of 10C, to an ideal summer maximum below 30C. Keeping plants cool in the summer is not easy in a greenhouse. The main challenge for an orchid house to grow cool tropical species is keeping temperatures cool in the summer. Standard greenhouses are glass to ground and designed to provide natural warmth in the spring and then hot conditions in the summer for crops such as tomatoes. You can see how my greenhouse is modified for thermal stability.
Firstly the greenhouse has a block wall up to three feet with a chalk bank built against it – the wall also provides 4000 litres of rainwater storage. The next step is double glazing inside with corrugated plastic to keep heating costs to a minimum. Then there is the permanent hurdles which provide deep shade up to the eves, and finally the green roof shade net that went on yesterday.
I find that with a lean-to greenhouse the perfect arrangement for shade is to support it on wooded poles above the vents.