Many orchids are easy to grow in a greenhouse as long as you care for them appropriately. Indeed, orchids will give a long lasting flower display. Many growers dedicate the whole greenhouse to an orchid collection. As any plant to grow they need light, air, water and food.
Orchids can be cool and warm growing and each genus has its own special needs. Orchids do not need soil as about half of the species are epiphytes. It means that they grow on the bark of trees in the wild. Other species are lithophytic meaning that they grow on rocks. However, there are some terrestrial species that grow in soil.
What is the best greenhouse for growing orchids?
A freestanding 14 feet wide and 14 to 20 feet long greenhouse is the best for growing orchids. It offers maximum sunlight and the environment is easy to control in comparison to lean- to and attached structures.
Even though the size might be too much for the initial collection, it will grow with time. You can also put the work bench in the middle. Also, it is cheaper to build a larger greenhouse straight away rather than adding an extension to the smaller structure in the future.
Do orchids do well in greenhouses?
Orchids will do extremely well in a greenhouse as long as you control the environment so it resembles the natural habitat for orchids. It includes monitoring temperature, humidity, lighting and ventilation. Moreover, it is very important not to generalize the temperature requirements for orchids.
Although you can grow orchids wired on to dead three branches, it is better to grow them in pots filled with orchid compost in the greenhouse. The key to success is in understanding where different orchid species come from. For example, Masdevallia orchid comes from the cool highlands of Ecuador. While Vanda orchid comes from a tropical Philippine rainforest.
How to grow orchids in a greenhouse:
1. Maintain appropriate temperature for orchids
There are more than 25,000 orchid species in nature and more than 100,000 hybrids. You can divide these species and hybrids into warm, intermediate and cool growing. Cool growing orchids prefer temperature of 85°F (27°C) during the day and 55°F (13°C) at nigh in summer.
In winter they can grow in 45°F (8°C) in a greenhouse and can tolerate temperature of 70°F (21°C) during growing season. Examples of cool growing species are Brassia, Cymbidium, Dendrobium, Lusidia discolor and Oncidium orchids. If you place them in warmer temperature they will stop flowering.
Intermediate growing orchids like Cattleya, Oncidium, Miltoniopsis and Paphiopedilum prefer a minimum temperature of 13-15°C (55-60°F) at night. During the day they tolerate temperatures between 65°F and 85°F (19°C and 30°C) depending on the season.
Phalaenopsis is the most popular species and is a warm growing orchid. It requires a minimum temperature of 65°F (18°C). In summer these plants can grow in 85°F (27°C) during the day. However, in winter temperature should be around 65°F (19°C) at night and 70°F (21°C) during the day.
2. Orchids need good light
Good light is essential for growing orchids – they need bright but filtered light. However, you should protect these plants from direct sunlight. Use roller blinds or shade cloth to screen orchids from warm direct sunlight. Too much light will burn the foilage.
When orchid gets enough light its foilage is lighter, yellow-green and it grows strong upright. How much light greenhouse captures depends on where you sit it. Position freestanding greenhouse on a north-south axis. That way sun will travel across the entire structure as it moves from east to west.
3. Good ventilation is necessary
Orchids need moist air at all times. That is why you need to put the pots on moist gravel. Good ventilation is a must but you need to avoid droughts at all costs. In nature orchids grow in windy locations. Orchid’s roots and eventually the whole plant will die if it doesn’t get enough air.
Also, orchids can’t tolerate stale and stagnant environment. So you need to make sure that they get gentle air movement at all times. You can’t solely rely on natural ventilation created with side and roof vents. Get a few fans that are going to be running continuously. That way you will move the air holding moisture throughout the greenhouse structure.
4. Water orchids once a week
Although orchids like high air humidity, their roots can rot easily if compost is too wet. That is why you should water them once a week with warm rainwater. You need to water them from above and drain excess moisture that collects under the pot.
Daily misting of foilage and aerial roots is beneficial. It is very important to reduce humidity in winter if temperatures are lower. So reduce watering in winter but keep the compost moist.
5. Use fertilizer to get better results
Orchid plants grow and flower with appropriate care for many years without fertilizer. Also, orchids are not heavy feeders. A balanced 20-20-20 fertilizer will provide all the necessary nutrients for plants. As a rule of thumb, you need to feed orchid plants every third watering during growing season.
However, for the best results feed them once a week in summer and every two weeks in fall and winter. Many orchids need a rest period during winter months. You need to water the plants first and add fertilizer when potting medium is wet.