Orchid Care Methods and Precautions in Autumn
Autumn is another golden season for growing orchids. Orchid growers should seize the characteristics of autumn climate and focus on adjusting light, repotting and dividing plants, supplying fertilizer and water, and controlling pests and diseases. Let's learn about it below.
1. Increase light and widen the temperature difference to promote flower buds and strengthen seedlings.
Autumn sunlight can enhance the orchid's ability to resist pests, diseases and severe cold. Therefore, in autumn, the shading level should be reduced as much as possible, and orchids should be exposed to more sunlight. At night, open the windows of the orchid room to allow full ventilation and air exchange, thereby widening the day-night temperature difference. Orchid growers all know that increasing light and widening the temperature difference in autumn is a quick way to promote flower buds and strengthen seedlings. In nature, the fact that orchids bloom more in places with more light also illustrates this point.
2. Watering and fertilizing.
In dry autumn with no rain for a long time, more attention should be paid to watering and moisturizing. If the humidity is too low, misting can be used to keep the environment moist and prevent orchid leaves from drying at the tips. After summer growth, most of the nutrients in the pot have been used up, so in autumn more attention should be paid to supplementing fertilizer. The method is to apply organic fertilizer every 10 days, and spray nitrogen fertilizer on the leaves about once every 10 days as well; the two can be alternated. In addition, while applying organic fertilizer to the root system, an appropriate amount of phosphorus and potassium fertilizer can also be mixed in. Phosphorus fertilizer has the function of promoting the sturdiness of orchid plants and flower bud differentiation. If the growing medium lacks phosphorus, it is generally very difficult for the plant to produce flowers. Usually, a 0.2% to 0.3% potassium dihydrogen phosphate solution can be sprayed on the leaves once every 5 to 7 days, for 2 to 3 consecutive sprays. Fertilization time should be chosen on a clear evening when the growing medium in the orchid pot is slightly dry and the temperature is below 30°C. The next morning, water once in time to keep the potting soil moist but not waterlogged, and never let the potting soil become too dry.
3. Pruning and tidying.
For Cymbidium ensifolium that blooms in summer and autumn, the flower branches should be cut off promptly after flowering and nutrients supplemented to strengthen the orchid plant. For orchids that are growing luxuriantly and are not yet due for repotting, the orchid leaves should be tidied in time. If the plants are too dense, some weak plants and diseased plants can be appropriately removed, and diseased leaves, dead branches and scorched leaf tips should be cut off to promote balanced and healthy growth of the orchid plant and maintain its ornamental value.
4. Division and repotting.
Because orchids are limited by the flower pot, strong and vigorous root clusters become coiled and intertwined, making it difficult for them to extend, and they continuously arch up toward the pot surface, bringing difficulties to watering and fertilizing. Too many plants in the pot create a dense, airless condition, which not only makes them susceptible to pests and diseases but is also very unfavorable to the growth of the orchid plants. In such cases, repotting can be carried out. For summer orchids and autumn orchids, late October to mid-November is the suitable period for repotting. When repotting, turn the mother plant out, gently remove the soil clumps, separate according to natural clusters, and prune dead roots and residual leaves, taking care not to injure leaf buds and fleshy roots. Then wash the roots clean with clear water, place them in a cool place, and pot them only when the root color turns white and appears dry.
5. Pest and disease control.
The autumn climate is suitable for the occurrence of various pests and diseases. Spider mites, scale insects, and white grubs are several major pests that harm orchids. A small number of scale insects can be brushed off with a brush; when the amount is large, a 40% dimethoate 800-1000 times solution can be sprayed for control. If spider mites are not controlled in time, orchid leaves can lose green color and become scorched. Use the pollution-free pesticide Lvying 500-600 times solution to spray and kill them. White grubs that burrow into the flower pot will bore into and feed on the fleshy roots of orchids, and in severe cases can cause the plant to wilt. A 5% phoxim 1000 times solution can be used to drench the roots for control, with 150 ml to 200 ml of medicinal solution per drench. In addition, autumn is also a season with a high incidence of orchid soft rot, stem rot, black spot and other diseases. Agricultural streptomycin, chlorothalonil, thiophanate-methyl and other fungicides can be used alternately for spraying. Not only should the orchid leaves be sprayed, but the surrounding areas should also be sprayed with the solution.