What are the main factors that affect how an orchid blooms?

The so-called "bloom quality" refers to how good the flowers of the same variety look after the buds open. Good bloom quality means the flower's color, petal shape, column, lip, shoulders and scape come as close as possible to the best evaluation standards for each part of the orchid, achieving a good visual effect; otherwise, the bloom quality is said to be poor.

There are many factors that affect the bloom quality of orchids: the potting medium, fertilizer, light, water, growing site, the vigor of the plant, and bud care all affect bloom quality. To obtain good bloom quality, it is necessary to study these factors. The works of orchid growers through the ages have touched on this. For example, in "A Brief History of Orchids and Huilan" (Lan Hui Xiao Shi), discussing the Huilan flower Wenyuan Mei, it says: the three petals are broad, large and thick, with a separated head and joined back, a hard pocket column, a dragon-swallowing lip, green color, level shoulders, and a long scape; at blooming time the potting soil should be dry, and it can still be so well-formed when it opens from a crowded clump. In "A Unified Record of Orchids and Huilan" (Lan Hui Tong Xin Lu), discussing Faxiang Mei, it says: only buds that emerge in spring have petals and lip indistinguishable, and often do not open; cultivation should aim for clean, vigorous growth, for if too vigorous, the three petals become a single nose-like mass. Since each variety has its own inherent bloom characteristics and differs in sensitivity to various interfering factors, varieties generally said to have "good bone and sinew" have more stable bloom quality, such as the Chunlan varieties Wang Zi, Long Zi, Gai He, and the Huilan varieties Lao Ran Zi and Jin Tian Su. But for most varieties, bloom quality varies greatly. Therefore, based on many years of observation and experience, the author discusses the influence of external factors on orchid bloom quality. 

1. The influence of plant vigor 

Generally speaking, the stronger the orchid plant and the more connected growths it has, the better it can express the variety's characteristics, and the flowers can receive sufficient nutrient supplementation, making the outer three petals broad and large. This is especially true for Huilan. For example, last year a particularly large Jiangnan Xin Jipin plant with six growths had secondary petals reaching 1.4 cm wide, while ordinary plants are around 1 cm. But for varieties such as Xi Shen, Ye Mei and Wan Zi, plants of medium vigor instead produce three petals that are rounded at the base. Of course, this is related to water supply during the flowering period (discussed below).

2. The influence of water during the flowering period 

During the flowering period, orchids rely on absorbing water to dilute the nutrients in their tissues and supply them to flower growth. If the plant has accumulated a lot of nutrients and the water supply is sufficient, then while the petal tips enlarge, the petal bases will also elongate, and the secondary petals will droop into fallen shoulders. This is unfavorable for the bloom quality of plum, lotus and fairy types, and lotus-petal types in particular will develop defects such as greatly fallen shoulders and open windows in the column petals. Therefore, slightly dry conditions in the pot are beneficial to bloom quality, especially for lotus-petal types and thin, floating petals. But too dry is unfavorable for raising the flower scape, so the difficulty lies in the word "degree." However, for multi-petaled strange flowers and wavy-petaled flowers, sufficient water can fully display their characteristics. 

3. The influence of fertilizer 

Too much fertilizer makes the overwintering nutrients in the plant quite abundant. Although this is beneficial for sending up new growth the following year, it makes it difficult to produce short, broad outer three petals. Therefore, for plum, lotus and fairy types and other "standard" flowers grown in humus soil, fertilizing should generally stop after buds appear, because the humus soil still contains considerable fertility, and the fertilizer supplied in the months before flowering shows a downward diagonal trend, exactly meeting the plant's later growth needs. Granular soil has poor fertilizer retention, so after buds appear, fertilizer is still needed to meet the plant's growth needs, but the concentration and frequency should gradually decrease. The problem is that this "degree" is also hard to grasp, and the generally poorer bloom quality of re-exported seedlings is one piece of evidence. For multi-petaled flowers, more ample fertilizer is beneficial to bloom quality.

4. The influence of light 

Flower color occupies an important place in bloom quality, and light control is the main factor determining flower color, especially for colored flowers. For purple, red and vermilion-gold flowers, buds receiving sufficient light can make the flower color deeper and more brilliant; but for flowers with red vein lines on the petals and dull green flowers, shading can make the flower color pure and lovely while reducing red pigment. Generally, for green-flowered lines, shading the buds makes the flower color tend toward tender green; and the vast majority of white flowers must be completely shaded to bloom white, for example, Xiao Xue Su, if not shaded, has petals that appear water-green while the veins are green.

5. The influence of temperature 

The temperature in late winter and early spring greatly affects bud development and opening. If the temperature is on the high side for a time around the Spring Festival, the buds of some varieties will open early, commonly called "borrowing spring to open." Such flowers generally do not open well, because the temperature at this time fluctuates between high and low and is unstable, and nutrient supply is not continuous. If artificial continuous heating and humidifying are used (generally around 18-25°C), the buds will receive sufficient and continuous nutrient supply, which is very beneficial for raising the flower scape and for the length and breadth of the petals. For example, to make the flowers open in time for the 10th National Orchid Exhibition in Hangzhou, we rented hotel rooms a week in advance for heating, and the effect was very good: tall scapes, large flowers and tender color. Among them, two pots of He Shen Mei had petals like soup spoons; by area, the three petals were one half larger than ordinary bloom quality, and there was no red or green at all on the reverse side. The excellence of their bloom quality was beyond expectation. But for some varieties prone to fallen shoulders, upward curling or open column petals, one should stop while ahead and move the flowers out of the heated room as soon as they first open. 

In short, these external factors and the condition of the plant affect orchid bloom quality in a combined and intersecting way. To obtain better bloom quality, different measures can be taken according to the characteristics of different varieties, using appropriate changes to these factors to achieve the goal of good bloom quality.