GREENHOUSE AND EQUIPMENT
When choosing a greenhouse, which is going to be used for the growing of begonias a few simple facts should be observed. During the summer months as much ventilation as is possible will be required, so both roof and side vents are necessary. The greenhouse should be as large as possible, to help to prevent wide fluctuations in temperature. Straight, rather than sloping sides, will provide more actual growing space. In short, a roomy well-ventilated greenhouseis what is needed.
During the winter and spring months, some form of heating must be provided. There are a variety of systems that can be chosen from, some more suitable than others. The most inexpensive to install is a paraffin heater. However, paraffin itself is no longer a low cost fuel and not suitable as the fumes affect the begonias' foliage, and very often it is not capable of producing sufficient heat to create a good growing atmosphere. Gas and electricity are more or less trouble free, solid fuel is satisfactory but requires constant attention. The best heating system is heat some form of hot water pipes ensuring an even distribution of the heat, but an electric fan heater does have the advantage of circulating air.
When starting tubers a propagator, which can be thermostatically controlled, is a great help. For germinating begonia seed, it is necessary. There are many different commercially made models to choose from, all excellent, but exactly the same job can be done using a soil warming cable connected to a rod thermostat. A box to house them can be constructed to suit the space available. A propagator will help to reduce heating bills by greatly reducing the area to be heated early on in the year.
The staging on which the plants are to be grown should be slatted, to help air circulate around the plants. The display when flowering will be greatly enhanced if the plants are tiered.
As the growing year progresses and the sun's rays become stronger, the greenhouse will have to be shaded to prevent the plants from being scorched. The most commonly used method is the application of a shading mix directly on to the glass. This can be made, by mixing one part emulsion paint to four parts water or alternatively Cool glass greenhouse shading mix can be purchased. Both are applied using a brush or sprayed on. The main disadvantage with this type of shading is that it is permanent and blooms may lose some of their colour in a prolonged spell of dull weather. This can be partially overcome by the use of a different commercial product called Varishade. This shading turns clear when it is wet. Another form of shading is the use of specially designed fabric, which is woven to filter some of the sun's rays, such as Netlon. Varying degrees of shade are available. Roller blinds can also be purchased and are perhaps the best form of shading, but costs are prohibitive.
Other accessories which will be required include: a sprayer which will deliver a fine mist for foliar feeding of plants, a fan, to help circulate air on really warm days. Finally, although not essential, automatic vents will help to improve growing conditions.