Growing Orchids in Summer: Learn to Use the Air Conditioner and They Will Bloom Beautifully

The hot summer temperatures and dry air have a serious impact on the growth and development of orchids. The most suitable temperature for orchids to grow in summer is between 25 and 28°C. Yet on summer afternoons the temperature can reach above 40°C, which is extremely unfavorable for orchid growth and can even cause orchids to stop respiration and photosynthesis due to the high heat, entering dormancy and ceasing to grow.

To regulate the temperature, gardening enthusiasts have adopted measures such as using electric fans to strengthen ventilation and spraying water around the orchid shelves to cool them down. Although these have some effect, it is difficult to bring the temperature of the orchid-growing environment down to the most suitable temperature for orchid growth. An air conditioner, however, can adjust the temperature in an orchid room fairly precisely, and using an air conditioner for orchids in summer can be said to be a very good cooling method. But if you want your orchids to bloom beautifully when using an air conditioner, there are still certain points to keep in mind.

Some gardening enthusiasts believe that since the air conditioner is used during the day and the temperature has already dropped by night, it can be turned off at night. This understanding is wrong. Because for most of the night in summer the temperature is still around 30°C, and without a relatively large temperature difference, orchid growth is not favored.

Other gardening enthusiasts do not use the air conditioner during the day but use it at night, causing the temperature to drop suddenly at night, with the aim of increasing the day-night temperature difference so that orchids store nutrients. This too is a mistaken understanding.

Because if the air conditioner is not used during the day, the excessively high temperature will put orchids in a semi-dormant state, hindering their photosynthesis so that they cannot absorb and synthesize enough nutrients for growth; and a sudden drop in temperature at night, if the day-night temperature difference exceeds 10°C, will prevent the orchids' respiratory function from working normally, which is also unfavorable for their growth and development.

In summer, to prevent the harm that high daytime temperatures cause to orchids, the correct way to use an air conditioner for cooling should be: generally, when the afternoon temperature exceeds 28°C, you can use the air conditioner to adjust the ambient temperature to between 26 and 28°C, which is suitable for orchid growth. This can promote the orchids' photosynthesis and regulate their respiratory function so that they grow and develop normally.

At night, orchids enter the dark-period growth stage, releasing through respiration the energy stored in their bodies during the day to maintain normal metabolism and nutrient accumulation, which better promotes the growth and development of orchids. The temperature difference between night and day should preferably be kept at around 10°C, as this is most suitable for orchid growth.

In addition, although an indoor air conditioner has a good cooling effect, the humidity is relatively low, so you need to regulate the air humidity and remember to sprinkle water with a spray bottle; you should also pay attention to strengthening supplementary lighting, because without sufficient photosynthesis, orchid growth will still be limited.

Also, in summer, some orchids have not yet entered dormancy, and at this time gardening enthusiasts need to supplement nutrients for their orchids. It is generally recommended to use an organic liquid fertilizer specially formulated for orchids. In the high summer heat, applying this water-soluble fertilizer together with watering gives good absorption without burning the roots, and it can both replenish water and add nutrients, promoting orchid growth.