Cultivation Methods, Seasons and Precautions for the Precious Medicinal Herb Dendrobium officinale

Dendrobium officinale is a precious Chinese medicinal herb, also known as Black Joint Grass, Yunnan Ironbark, Ironbark Dendrobium, etc., and is hailed as the first of the “nine immortal herbs”. Below, the editor will explain the cultivation methods and precautions for Dendrobium officinale.

Dendrobium officinale is also known as: Black Joint Grass, Yunnan Ironbark. It belongs to the Microspermae, a perennial epiphytic herbaceous plant of the Orchidaceae family. The stem is erect, cylindrical, 9-35 cm long, 2-4 mm thick; the sepals and petals are yellow-green, nearly similar, oblong-lanceolate, about 1.8 cm long, 4~5 mm wide; the flowering period is March to June. It is mainly distributed in Anhui, Zhejiang, Fujian and other places in China. Its stem is used as medicine, belonging to the yin-nourishing medicines among tonic medicines: it benefits the stomach and promotes fluid production, nourishes yin and clears heat.

It grows on semi-shaded, moist rocks in mountainous areas at altitudes of up to 1600 m. It is mainly distributed in Anhui, Zhejiang, Fujian and other places in China. Its stem is used as medicine, belonging to the yin-nourishing medicines among tonic medicines: it benefits the stomach and promotes fluid production, nourishes yin and clears heat.

Pot Cultivation Methods

1. For the planting material of potted Dendrobium, use 2-3 cm particle-size stones in the bottom one-third of the pot, and cover the surface of the upper two-thirds with finely crushed bark and small stone particles.

2. The best season for dividing and transplanting Dendrobium into pots for propagation is from the Spring Equinox to Qingming. This period is the sprouting season, and new buds will grow immediately after planting. Pay attention to the depth: if too deep, the sprouting points will be buried below the planting material, which will affect the sprouting rate; if too shallow, the roots will find it difficult to retain moisture, which will affect growth. Attention must be paid to the season and cultivation techniques.

3. Maintenance and management: Home cultivation of Dendrobium varies with different environments, and the methods also differ. On balconies or window frames where rain cannot fall directly, during the spring period, because Dendrobium is a herbaceous plant that loves sunlight, direct sunlight is suitable; for open-air balcony cultivation, attention should be paid to heavy rain or excessive rainfall, which can easily cause root rot and seedling collapse, so a canopy cover should be used for protection. Specifically according to actual conditions, watering is generally once every 5-7 days, but it must not be too wet or too dry.

4. Summer and autumn seasons: on balconies or window frames not exposed to rain, spray water once every day at 6 a.m.; for open-air balconies, to prevent rain or strong direct sunlight, cover with a shade shed and strengthen ventilation.

5. In winter, on balconies or window frames, spray water once every 7-10 days; direct sunlight is suitable; below 5°C, do not spray water or fertilize; just smash longan shells, lychee shells, etc. and place them on the pot surface. Pay attention to preventing snails.

Harvesting: harvest each year in late spring when sprouts appear. When harvesting, cut off stems and branches that are more than three years old, leaving young sprouts so they can continue to grow.

Field Planting Methods

Site selection and land preparation

According to its growth habits, the cultivation site for Dendrobium officinale should be chosen in a semi-shaded and semi-sunny environment, with air humidity above 80%, and in areas where winter temperatures are above 0°C; artificially controllable environments are also acceptable. The tree species should be living trees such as Huangjue trees, pear trees, camphor trees, etc., with thick bark, longitudinal grooves, high water content, dense branches and leaves, and thick trunks. Stone plots should also be in cool, moist areas, with moss growing on the stones and a small amount of humus on the surface.

Propagation Methods

Tissue rapid propagation

Before cultivation, tissue-cultured seedlings should first undergo 14~21 days of hardening. The specific measure is to move the tissue-cultured seedlings to a hardening room so that they gradually adapt to the natural environment in an open and changing environment. When the leaves of the tissue-cultured seedlings become dark green, they can be taken out of the bottles for planting.

Before taking them out of the bottles, first open the bottle caps and let the bottle seedlings stand in outdoor air for 2~3 days so they adapt to natural temperature and humidity. Then wash the seedlings. When washing, gently take out the seedlings with culture medium and place them in a basin for cleaning. Contaminated seedlings, bare-root seedlings, or seedlings with few roots should be placed separately. Tissue-cultured seedlings should first be washed with tap water, mainly to wash off agar, so as to avoid mold on the agar causing root rot, and then rinsed once with clean water. When washing seedlings, it is best to grade them simultaneously according to size and quality, so as to facilitate cultivation and management, improve the survival rate of tissue-cultured seedlings, and make their growth uniform.

Division and cutting propagation

When dividing, select 1-year-old or 2-year-old plants with tender green color, robustness, many sprouts, well-developed root systems, and no pests or diseases as stock plants. Cut off dead branches, broken branches, old branches, and overly long fibrous roots, cut the clumps apart, and divide them into small clumps, each with 5~7 leafy stem plants, and then they can be planted.

Field management

(1) Watering—In the later stage after planting Dendrobium, if air humidity is too low, water frequently to retain moisture. A sprayer can be used to water in the form of a spray.

(2) Topdressing—During the growing season of Dendrobium, attention should be paid to topdressing. A mixture of decomposed peanut meal, rapeseed cake, superphosphate, etc. with river mud can be spread at the roots. In addition, 1000-fold Jiamei Hongli and Nao Baijin can be used for foliar topdressing.

(3) Pruning—Each spring before new buds appear, in combination with harvesting old stems, cut off dead stems within the clump, and remove diseased stems, weak stems, and diseased roots. After 6-8 years of planting, depending on the growth of the clump base, turn over the clump and divide and propagate again.

Cultivation Techniques

Transplanting time

The cultivation time for Dendrobium officinale is generally the two seasons of spring and autumn each year, and spring is better than autumn. In the Zhejiang area, the best time for cultivating Dendrobium officinale is from mid-April to late June each year. During this period, the temperature is 12~25°C, and air humidity is relatively high, so the survival rate of transplanted test-tube seedlings after being taken out of bottles is relatively high and the growth time is relatively long. The next best period is from mid-September to late October. During this period, special attention must be paid to cold resistance and freeze prevention when transplanting.

Cultivation substrate

The cultivation substrate is the key to high-quality and efficient cultivation. The biological characteristics of Dendrobium officinale require the cultivation substrate to have both good water retention and ventilation and air permeability. Large-scale production requires the cultivation substrate raw materials to be readily available and easy to handle. Substrates reported include sphagnum moss, crushed stone, peanut shells, moss, coconut bark, pine bark, sawdust, charcoal, wood blocks, etc. In production, the main materials used are bark and sawdust, or a mixture of bark, sawdust, crushed stone, and organic fertilizer, in which the bark is crushed into particles of 2~3 cm or less.

Cultivation conditions

The cultivation of Dendrobium officinale requires a greenhouse. The construction of the greenhouse must achieve ventilation, shading and rain protection, and insect-proof netting, and according to the growth habits of Dendrobium officinale, natural factors such as light, temperature, humidity, and ventilation of the site should be considered. The suitable temperature for the growth of Dendrobium officinale is 15~30°C. In the Zhejiang area, summers are relatively hot, and generally 80% shade netting is used for coverage, with the plastic film opened to help lower the temperature; winters are relatively cold, and under 30%~50% shading, double-layer plastic film is used to seal and keep warm. Dendrobium officinale requires the substrate to remain moist, and it is best to keep air humidity above 80%, but there must be no water accumulation. When watering, sprinkler irrigation or drip irrigation is best, and flushing irrigation must not be used. The amount of watering also differs in different seasons and different regions.

Host plant cultivation

Dendrobium officinale is an epiphytic plant. Under natural conditions, it mainly grows on the shaded and moist trunks of tall trees or on limestone. Therefore, under artificial breeding and cultivation conditions, it can also be planted by simulating natural environmental conditions. According to the different characteristics of the host, artificial host cultivation of Dendrobium officinale can be divided into three forms: tree cultivation, stone cultivation, and humus soil cultivation.

For tree cultivation, broadleaf tree species with thick bark, high water content, dense crowns, leathery or waxy leaves, and bark with longitudinal grooves (such as Huangjue trees, pear trees, camphor trees, etc.) can be selected as cultivation hosts; for stone cultivation, stones with rough texture, loose and porous and easy to absorb moisture, and with humus soil or moss attached to the surface are selected as cultivation hosts; for humus soil cultivation, choose a relatively cool and moist forest area, build raised beds 15 cm high with bricks or stones, mix humus soil, fine sand, and crushed stone evenly and fill them into the beds, level them, and then plant. A shade shed 100~120 cm high is erected above the bed surface.

What Season to Plant Dendrobium officinale

Because Dendrobium officinale is a perennial herbaceous plant of the Orchidaceae family, belonging to the aerial or epiphytic type, wild Dendrobium officinale has an extremely unique growing environment and relatively strict requirements for its growing environment, limited by moisture in the climatic environment, especially air humidity. In the cultivation of Dendrobium officinale, it grows best at a relative humidity of about 70%, forest transmittance of about 60%, and the most suitable temperature during the growing season is between 15 and 32°C.

The cultivation time for Dendrobium officinale is generally the two seasons of spring and autumn each year. The best time for cultivating Dendrobium officinale is from mid-April to late June each year. During this period, the temperature is 12~25°C, and air humidity is relatively high, so the survival rate of transplanted test-tube seedlings after being taken out of bottles is relatively high and the growth time is relatively long; from mid-September to late December, special attention must be paid to cold resistance and freeze prevention when transplanting during this period.

Disease Control

Dendrobium soft rot

It easily occurs in high-temperature and high-humidity environments, and develops quickly. In severe cases, the entire plant rots and disintegrates into a wet rot.

Control method: In the early stage of the disease, 77% Keshade 101 wettable powder at 2 000 mg/kg has the best control effect, and after spraying, the control effect can reach more than 78% after 12 d. It can also be sprayed with 80% Thiophanate-methyl wettable powder 800-fold solution. At the same time, strengthen management in the greenhouse, pay attention to ventilation and light transmission, and reduce humidity in the greenhouse. If diseased plants are found, remove them promptly and use broad-spectrum antibacterial agents such as Thiophanate-methyl, Carbendazim, Kobo, etc. for disinfection and sterilization, then replant with sterilized substrate.

Dendrobium black spot disease

It harms leaves, causing them to wither, and generally occurs from March to May.

Control method: Spray with 50% Carbendazim 1000-fold solution 2~3 times.

Dendrobium anthracnose

It harms leaves and fleshy stems. Affected leaves develop brown or black lesions, and it generally occurs from January to May.

Control method: Spray with 50% Carbendazim 1000-fold solution or 50% Thiophanate-methyl 1000-fold solution 2~3 times.

Snails

Common pests that damage young stems, tender leaves, flower buds, and young fruits.

Control method: Hand capture, poisoned bait trapping, or spreading lime or tea seed cake can be used for control.

Dendrobium scale insect (Phenacaspis dendrobii)

It parasitizes on the edges or undersides of plant leaves and sucks sap, with late May being the peak hatching period of damage.

Control method: Spray with 40% Dimethoate emulsifiable concentrate 1000-fold solution or 50% Malathion 1000-fold solution to kill insects, or burn old branches where the scale insects are concentrated.

Red spider mites

Control method: It can be controlled by clearing weeds in the surrounding environment or spraying 800~1000-fold low-toxicity acaricides, such as 40% Dicofol.