Growing tropical, heat-loving plants in the home can be a challenge. They prefer temperatures much warmer than room temperatures indoors during winter. The solution is to grow such tropical plants in a greenhouse. Unfortunately, a greenhouse is almost all glass and heat leaks through glass quite easily. However, there are certain steps you can take to minimise heat loss from your greenhouse, as well as keep it warm enough for your tropical plants to grow and thrive.
Erect the greenhouse as a lean-to against your house, rather than as a free-standing building. The lean-to will absorb some heat from your home and help raise its temperature both during the day and at night.
Double-glaze the tropical greenhouse. Double-glazed windows block more heat from escaping through the glass than single-glazed windows do. This will keep the sun's heat from escaping through the glass, especially at night.
Install a heater in the tropical greenhouse. For true tropical growing conditions, keep the greenhouse above 23.9 degrees Celsius during the daytime, with 25.6C even better. Do not allow nighttime temperatures to fall below 20C.
Grow plants on shallow saucers filled with pebbles or small gravel. Fill the saucers with water to just below the level of the tops of the rocks. The water will evaporate and add humidity to the greenhouse, mimicking tropical conditions. Create even more humidity in your greenhouse by running a humidifier or setting buckets of water near the plants.
Keep plants off the floor if at all possible. This is especially important in cold northern areas, where freezing winter temperatures are the norm. Because cold air settles, it will fall below the level of the plants' roots if they are placed on benches, overturned empty pots or other supports.
Close off the outside entrance during the winter months, to minimise cold air entering the space.