Why won't orchids bloom? Growers share their experience

I often hear from fellow orchid growers that their orchids have not bloomed after several years of care, and they do not know the reason why orchids fail to bloom. Generally speaking, a normal mature orchid, as long as it has formed a connected plant of two or three growths or more, can under normal circumstances bloom if it is cultivated properly (a small number of single-growth orchids can also bloom; the thick-rooted, narrow-leaved Cymbidium kanran often does). The reasons can be broadly grouped into the following aspects:

1. Seedling orchids (seed-grown orchids) and tissue-culture orchids may not necessarily bloom even after many years of cultivation. Just like other plants, for example fruit trees must reach a certain age before they can bloom and bear fruit, orchids must also reach a certain age before they can bloom and set seed.

2. The species differences among the various orchid types and the different climatic conditions in different regions often make it difficult for orchids to bloom. Take Cymbidium goeringii for example: in some regions it is relatively difficult to bloom, or rather fewer of them bloom. For instance, in Hainan or southern Guangdong, the four-season temperatures are relatively higher and more even than in most other parts of the country, so even if Cymbidium goeringii produces flower buds there, it cannot bloom because it does not receive the normal conditions for spring flowering (low-temperature conditioning) (I have heard this but have not verified it). There are also other orchid types that fail to bloom or cannot bloom normally because of the large latitude differences between the north and south; for example, some wild orchid types are extremely sensitive to climate and will never bloom again once moved to a place with a relatively large climatic difference. However, such orchid types are few. Among Chinese orchids, Cymbidium goeringii, Cymbidium ensifolium, Cymbidium faberi, Cymbidium tortisepalum, Cymbidium faberi var. and Cymbidium sinense, Cymbidium kanran can bloom in most provinces nationwide, and nowadays air conditioning and solar greenhouses can be used artificially to regulate temperature and thus promote orchid growth and flowering.

3. The physiological growth of the orchid is disrupted for various reasons, and new leaf buds emerge suddenly during the flower-bud formation period. In this case, the orchid plant no longer has enough nutrients to maintain the normal differentiation of the flower buds, which causes the flower buds to stop growing and fail to bloom.

4. Improper cultivation methods can also lead to orchids not blooming. Here there are mainly the following situations: 1. The orchid's growing medium contains too much nitrogen fertilizer and relatively little phosphorus and potassium fertilizer, which leads to excessive vegetative growth and inhibited reproductive growth. Just like fruit trees planted by farmers around their houses: because the soil is too fertile and household waste and poultry and livestock manure are often dumped on it, the trees only grow branches and leaves without blooming or bearing fruit, and orchids are the same. The solution is to replace the medium with one that has balanced nitrogen, phosphorus and potassium nutrition or to increase the application of phosphorus and potassium fertilizer. 2. Watering too much during the flower-bud differentiation period and keeping the medium too moist will likewise lead to vigorous vegetative growth and inhibit reproductive growth. Because the medium is too moist, the nutrients contained in it are constantly released and absorbed by the roots together with water, then transported to the leaves to take part in the plant's metabolism. Once metabolism is strong, respiration becomes vigorous, thereby offsetting the products of leaf photosynthesis. The accumulation of organic matter in the orchid plant is affected, and flower-bud differentiation lacks the necessary driving force.

The solution is to properly control water for the orchids in July and August each year (the flower-bud differentiation period for most orchids), keeping the medium on the dry side, and at the same time spray the leaves with monopotassium phosphate once every 10—15 days, spraying two to three times in succession, which is beneficial to the differentiation and formation of orchid flower buds. 3. Insufficient light is also one of the reasons orchids do not bloom. Although orchids are shade-loving plants, they still need a certain amount of sunlight to maintain normal physiological activity. With sufficient light, orchids accumulate relatively more organic matter, and flower-bud formation has enough driving force. Some growers, due to limited conditions, have to grow orchids indoors, so naturally they bloom relatively less. The solution is to let orchid plants that cannot get sunlight enjoy as much sunlight as possible (of course they must not be exposed to scorching sun), especially the warm, soft sunlight of the morning. Besides light, the accumulation of photosynthetic products (organic matter) also depends on the temperature difference between day and night. If the day-night temperature difference is small, the orchid's respiration at night is vigorous and will consume the photosynthetic products produced during the day. Therefore, in areas where the day-night temperature difference during the flower-bud formation period is small and orchids often have difficulty blooming, consideration should be given to artificially creating a day-night temperature difference.

5. There is also a situation in which the orchid itself cannot bloom for special reasons, or rather a very small number of orchids do not much like to bloom. This phenomenon has appeared in various orchid types, and I have encountered it myself: a plain-bud Cymbidium ensifolium collected locally in 2004 has been cultivated in this garden for six or seven years and has multiplied to more than a dozen pots, yet to this day it has never been seen to bloom. This is probably the infertility phenomenon of plants (orchids)!