Detailed Explanation of Key Technical Points for Greenhouse Cultivation of Flowers

I. Types of Greenhouses

1. High-temperature greenhouse: the winter temperature is maintained above 15°C, used for cultivating flowers native to the tropics and for forcing flowers into bloom.

2. Medium-temperature greenhouse: the winter temperature is maintained at 8-15°C, used for cultivating flowers native to the border regions between the tropics and subtropics, such as fishtail palm, areca palm, and cacti from tropical high-altitude deserts.

3. Low-temperature greenhouse: the winter temperature is maintained at 5-8°C, used for cultivating flowers native to the subtropics, such as Chinese hibiscus, white magnolia, and jasmine.

4. Cold room: the winter temperature is maintained at 0-5°C, used for overwintering and cold protection of flowers native to the warm temperate zone, such as osmanthus and citrus.

II. Equipment Inside the Greenhouse

1. Plant benches and planting beds. A plant bench is a rack for holding potted flowers, mostly used for potted flower cultivation; a planting bed is a facility for growing flowers in the greenhouse, such as the cultivation of cut flowers like carnations, African daisies, and freesias.

Plant benches come in two forms: flat benches and tiered benches. Flat benches are usually placed on the south side of a single-slope greenhouse or on both sides of a double-slope greenhouse; in larger greenhouses, they can also be placed in the middle. The height of a flat bench is generally 80 cm, with a width of 80-100 cm; if placed in the middle with walkways on both sides, its width is 150-200 cm. Tiered benches are usually placed on the north side of a single-slope greenhouse or in the very center of a double-slope greenhouse. Tiered benches can make full use of greenhouse space, with good ventilation and even lighting, but they are inconvenient to manage, suitable for display greenhouses and specimen preservation, and not suitable for large-scale production applications.

Plant benches can be divided into three types: wooden, iron frame with wooden boards, and concrete. The first two types have bench surfaces made of wooden boards; if only potted flowers are placed, boards 6-15 cm wide and 3 cm thick can be laid out, with a 2-3 cm gap left between boards to facilitate drainage, and the bench surface height is about 20 cm lower than the low wall.

A planting bed refers to a facility for growing plants directly in the ground or on raised ground within the greenhouse; the former is called a ground bed, and the latter is called a raised bed. Its sides are made of bricks or concrete, with soil added inside.

2. Propagation beds

In single-slope greenhouses and asymmetrical greenhouses, propagation beds are set against the north wall, since they are mostly used for cuttings and the light should not be too strong; generally the bed is about 100 cm wide and 40-50 cm deep, with glass windows on top, and the lower part down to the heating pipes is fully enclosed to prevent temperature loss. The bed bottom is paved with cement bricks, and the lower part is 40-50 cm from the heating pipes. Electric heating wires are now mostly used for heating.

3. Water pools and water tanks

The temperature of irrigation water for greenhouse flowers should be close to room temperature. Therefore, irrigation water must be stored in indoor pools in advance to raise its temperature. Usually water is filled into the pool the day before and can be used the next day. Water pools are generally set under plant benches or on the north side of the greenhouse. The shape of water pools is variable, with square and rectangular shapes being the most common, and water pools are all built with bricks and cement. The depth and size vary depending on water demand, generally about 100 cm deep. If tap water is available, a water tank can be installed at a high place, with water stored in the tank the day before, and a rubber hose used to lead water for irrigation, which is more convenient. In addition to supplying water, water pools can also increase air humidity. When cultivating flowers in the greenhouse that require higher air humidity, such as ferns, tropical orchids, and begonias, the area of ground water pools can be expanded to increase air humidity.

The simplest method of greenhouse heating is to pass flues through the ground or pipes through the upper space of the room to heat the indoor air; the next is to use hot water pipes; a few use steam pipes for heating.