To enable the most suitable environment to be created for your orchids, the best place to keep them is in a greenhouse. By devoting the whole area to orchids, you can concentrate on getting the conditions just right.
If you are starting from scratch, there are many different greenhouse designs from which to choose; select whichever one best suits the position and aesthetics of your home. Consider the position of the greenhouse carefully. If the structure is built under deciduous trees, they will provide the necessary shade in summer, but evergreen trees will also block the light during the dull months of the year when it is needed. Having the greenhouse in an open position makes it easier to control the light levels, since you can apply and remove shading at different times of the year as required. Use shade netting attached to the roof or apply shading paint to the glass, or a combination of both. Remember, though, that a greenhouse in an exposed position will not be sheltered from the wind, which can cause extensive damage.
Wooden greenhouses tend to dry out more slowly than metal ones, so you may want to bear this in mind. Traditionally, all greenhouses were made of glass sheets; this is still the cheapest way of providing a strong shell, but the glass can break, especially in windy weather. Polycarbonate sheeting, although more expensive initially, is an extremely economical method of greenhouse roofing and can be obtained in many different forms. It comprises two or three layers of rigid plastic sheet, joined by thin walls that hold the sheets apart, forming air pockets which provide excellent insulation. The polycarbonate can also be tinted to give permanent shade.
If your greenhouse is glass, extra insulation can be created by lining it with thick bubble-plastic sheeting. This also helps to block any draughts. Regular inspections should be made to close any gaps that form between the panes.
Strong, moveable staging is essential for your orchids and can be set at whatever height suits you and the plants. Larger plants can be positioned closer to the ground, for example, and smaller ones higher up. The staging should be made of open slats or mesh to enable water to drain away freely from the bases of the pots. To increase the available space in your house, think of it in three dimensions, using the space above the staging to hang orchids in baskets or hanging pots. Those that prefer more light will enjoy being higher up and will create a little shade for the ones underneath. Take care not to pack your house too full though, as this can reduce the light reaching the plants and they may not grow or flower as well.
You may also like to make use of the walls by growing plants mounted on pieces of cork bark. These can be suspended on mesh fixed to the sides of the greenhouse where they can be sprayed regularly to keep them moist.
The space underneath the benches can be a little dark for most orchids but is ideal for companion plants that enjoy a shady, humid spot, such as ferns, bromeliads and other foliage plants. Keep these in pots or plant them in the ground under the benches. Check these plants regularly as they can harbour pests that may spread on to your orchids.
The companion plants also help to increase the humidity in the greenhouse. Rainforest plants do not live alone and will grow better in the company of other plants.
Humidity is easy to create in a greenhouse by damping down the floor with water each morning, especially in hot weather. In cooler or dull weather, spraying is not so essential and can be damaging to flowers and sometimes even the plants themselves if the water collects on the foliage. You can also apply a light misting to the orchids’ leaves, including the undersides. As well as raising humidity, this helps to keep them free of dust and pests.
Certain orchids such as vandas, which grow without any compost around their roots, rely on regular misting to prevent dehydration.
Misting can be done on a daily basis, but this may not provide enough water for many orchids. They also need to be given water at their roots and this is easily done when they are growing in a greenhouse. For greater efficiency, use a watering lance attached to a hosepipe that is long enough to reach all the plants without the need to continually refill a watering can. The lance can be used with a variety of roses and misting heads to suit most needs. If you cannot arrange a mains water supply in your greenhouse, set up a water tank inside which can be filled regularly. This means the water will be at a warmer temperature to use in the winter. Try to fill the tank with rainwater.
If you are growing orchids that require warmer temperatures, you will obviously need to heat the house more often, so the most efficient method is preferable. With gas-fuelled heating, it is important that there is plenty of ventilation, as the fumes can be harmful to the plants as well as to the grower if allowed to build up. If you are not able to connect to a gas main, a paraffin heater will work well. Electric fan heaters are effective at circulating the heat around the greenhouse but can create a rather dry atmosphere, so regular spraying maybe necessary to maintain the humidity. Oil heaters are not as cost-effective but can be used as a back-up system in case of emergency.