There are various grades of polythene sheeting for fixing to the glazing bars with drawings pins or a stapler. For an aluminium house there are specially-designed clips. A totally sealed greenhouse will give the grower a fresh crop of problems. Condensation will build up on the polythene and reduce the light drastically in the winter when every bit of light is of benefit.
It should be placed near the floor, below the plants, to allow the cool vapour to reach the plants standing above. Within a few weeks of introducing a humidifex into the greenhouse or home you should see a noticeable increase in aerial root activity on your orchids.
These days of high fuel costs the most expensive item required in determining an orchid collection in the northern hemisphere is the Ming. Prevention of heat loss is the aim of every grower, and insulation of the greenhouse will make a great saving on fuel.
There are two main areas where insulation can be beneficial. One is below the staging level where the greenhouse is built on brick or wooden foundations. This whole area can be lined with polystyrene, polythene or other insulation boards which will withstand the moisture and humidity. Insulating the door and ventilators with any of the proprietary brands of polythene on the market is a necessary step to keep out draughts. If double glazing with glass is used this mould have been allowed for in the original construction of the henhouse.
The little plants cannot be knocked off, and the compost will dry out less quickly. Providing that sufficient fall is put on the shelving, there is no danger of excess water collecting in the gutter. As the surplus water will run out of the end it will not harm the plants on the shelf below. Plants housed in this way usually do extremely well as they are easily looked after and there is no danger of the one at the back’ being missed at watering time.
Either north or south ends of the house are suitable, or the guttering can run the full length of the greenhouse at about eye level. Place two thin strips of wood or plastic in the base of the guttering, to raise the pots slightly from the floor and allow a clear run of the surplus water, thus preventing puddles resulting in the plants being saturated.
