How long does vernalization generally take for orchids?

   Orchid vernalization refers to the low-temperature process that orchids must undergo during their reproductive growth period. The orchid seedlings and buds enter dormancy and almost stop growing, accumulating dry matter nutrients to supply the flower buds. It plays a role that cannot be ignored in promoting the growth of flower buds, and the vernalization time for orchids varies greatly depending on the region.

Different orchid varieties also have different requirements for vernalization temperature. For example, Jianlan (Cymbidium ensifolium), Hanlan (Cymbidium kanran), and Molan (Cymbidium sinense) do not need special low-temperature vernalization and can bloom naturally, but the temperature for Molan from the bud stage to before blooming and even during the flowering period is best kept between 10-15°C. If the temperature is too low or too high, Molan is prone to developing stiff buds and bud abortion. Even if it barely opens, the flowering quality is very unsatisfactory, and the charm is greatly reduced.

Many orchid enthusiasts wonder: when is the most suitable time to vernalize orchid plants with flower buds? For orchid enthusiasts in orchid-producing areas, there is no need to worry about this question at all; just let nature take its course [except for controlling the flowering period for exhibitions] and let them bloom normally. For orchid enthusiasts in the north, the timing must be chosen appropriately. Usually, when the flower bud emerges from the soil about 3-4 cm, stops growing taller, and appears slightly round and plump, vernalization can begin as long as the temperature at the vernalization site is appropriate [4-10°C]. During the vernalization period, the ideal temperature is between 4-10°C. If the temperature is too low or too high, it will have a certain impact on the growth of the flower bud, bud pregnancy, and nutrient accumulation. Humidity should not be too high, as it easily causes root rot and flower bud rot. Therefore, as the situation permits, keep it on the drier side and delay watering time.

The vernalization duration is for orchid enthusiasts' reference only. Of course, the more thorough the vernalization, the better. Usually, Chunlan (Cymbidium goeringii) needs 30-40 days of vernalization. Chunlan from the Yunnan-Guizhou-Sichuan region has lower vernalization requirements and is relatively easier; some can even bloom normally without vernalization. For Chunlan from the Jiangsu-Zhejiang region, due to factors such as geography and climate, it is better to appropriately extend the vernalization time. For Chunjian (Cymbidium tortisepalum) and Lianban (Cymbidium tortisepalum var. longibracteatum), about 40-50 days is appropriate. For Huilan (Cymbidium faberi) and Songchun, it is best to have more than 60 days. In order to enable the orchid plant to achieve the effect of accumulating nutrients through vernalization, before vernalization, spray the leaves once with a 1000-fold dilution of monopotassium phosphate, and then begin vernalization. This promotes nutrient accumulation, resulting in larger flowers and more vivid colors. During the vernalization period, avoid applying nitrogen fertilizer, because at the lower vernalization temperature, orchid seedlings cannot absorb nitrogen fertilizer and are prone to fertilizer burn and root rot.

After vernalization is completed, water thoroughly [avoid getting water into the flower buds, which can cause bud rot]. The orchid pot can be placed in a location at around 15°C for 1-2 days, then moved to normal room temperature. This can effectively avoid heat-induced stiff buds and bud abortion caused by a sudden temperature rise. After moving to normal room temperature [18-24°C], the flower stalk usually shoots up rapidly [except for certain varieties], and within about 5-15 days the buds line up and the flowers open.

Watering after vernalization is completed should be handled appropriately according to different potting media. Usually, for petal-type flowers [lotus petal, plum petal, narcissus petal, etc.] and colored flowers [red flowers, golden-yellow flowers, pink flowers, etc.], try not to let the potting medium become too wet for 7 days before and after flowering. Keeping it slightly on the drier side for flowering gives more ideal petals and color; otherwise, the petals will quickly elongate, the shape will change and the color will fade, and the fragrance will also be greatly reduced [for colored flowers, after vernalization is completed, it is best to keep the temperature slightly lower during the flowering period, and the color will be even better]. For odd-type flowers, it is the opposite, especially multi-petal odd flowers. Keep them on the wetter side. If water is insufficient, some small petals will appear semi-dehydrated when flowering and will not look spirited enough. Sufficient water will make them bloom even more outstandingly and beautifully.