How to grow Dendrobium nobile? Detailed explanation of the key points of cultivation and management techniques

Orchid family plant Dendrobium nobileDendrobium, also known as flat golden hairpin, hanging orchid. A perennial herb, 20-50 cm tall, with white aerial roots. Stems upright, clustered, yellow-green, slightly flattened, grooved, jointed. Leaves alternate, sessile, narrowly oblong-elliptic, leaf sheaths clasping the stem. Racemes borne laterally, with 2-3 small flowers, flowers white, apex slightly tinged with pale purple; capsules elliptic, with 4-6 ribs; seeds tiny. Flowering period May-June, fruiting period July-August. The stem is used as medicine, nature cold, taste sweet, with effects of benefiting the stomach and promoting fluid production, nourishing yin and clearing heat, and can be used to treat conditions such as yin damage with insufficient fluids, dry mouth and excessive thirst, and poor appetite with dry retching.

1. Site selection and land preparation. For cultivating Dendrobium, a semi-shaded and semi-sunny environment should be chosen, with air humidity above 80% and winter temperatures above 0°C. Tree species should be living trees such as yellow cypress, pear, camphor, etc., and should have thick bark, longitudinal grooves, high water content, dense branches and leaves, and thick trunks. Stone areas should also be in cool, moist locations, with moss growing on the stones and a small amount of humus on the surface. Before planting Dendrobium, the plot must first be prepared. The basic requirements are: when planting Dendrobium on large rocks, holes should be drilled on the stone surface with a drill at a spacing of 30 cm × 40 cm, with a hole depth of 5-10 cm, and a small drainage outlet should be made on the lower side of the stone surface to prevent water accumulation from causing rot at the base; when drilling holes, protect the moss on other parts of the stone surface. When planting Dendrobium on small gravel, remove weeds and miscellaneous branches in the field, reserve shade trees, and clear out excessive and overly dense small miscellaneous trees to help increase light penetration.

2. Propagation methods. Because Dendrobium seeds are extremely small, with about 20,000 seeds in each capsule, they generally need to be cultured in a tissue culture room. In actual small-scale production, asexual propagation is commonly used, carried out in spring or autumn. Select plants 1-2 years old with good growth vigor, no pests or diseases, well-developed root systems, and many sprouts as stock plants. Pull them up with roots, remove dead branches and broken branches, cut off overly long fibrous roots, keep old roots at about 3 cm, and divide them into several clumps according to the number of stems; each clump must have 4-5 stems before it can be used as planting material.

3. Planting methods. Dendrobium is best planted in spring (March-April) and autumn (August-September), with spring planting being more suitable than autumn planting. ① Stone-attached planting method. Choose shady, damp areas under the forest in stone crevices or stone grooves with humus, wrap the root portion of the Dendrobium seedlings divided into small clumps with cow dung slurry, and insert them into rock crevices or grooves; when inserting, strive for stability to prevent them from falling. If cultivating on gravel, the method is to place the seedlings flat on the gravel, then use stones to press down the middle and lower parts of the seedlings, leaving the base and top exposed, with the degree being that wind cannot move them. When planting Dendrobium around the stone surface, a small hole can be drilled with a drill; beforehand, mix phosphate fertilizer into fresh cow dung at 30:1, add water and tread to mix, with the degree of thinness such that no water remains in the finger gaps when squeezed by hand, press the Dendrobium seedlings tightly against the small hole, and with one hand grasp the prepared cow dung and place it on the middle and lower part of the Dendrobium seedling stems, so that the seedlings are firmly attached to the stone. ② Tree-attached planting method. On relatively flat and thick trunks or branches, in recesses or every 30-50 cm, use a knife to cut a shallow slit and peel off some bark, then fix the prepared Dendrobium seedlings at the base in the tree slit with bamboo nails or ropes, and then apply cow dung slurry (made by mixing cow dung and mud slurry evenly) to the roots and surrounding bark grooves. To prevent wind from moving them and rain from washing them away, generally bamboo nails should be used to nail them firmly or bamboo strips and other ropes should be used to tie them for 2 rounds, to fix the Dendrobium fibrous roots and plants on the trunk or tree fork. When planting on trees, proceed from top to bottom.

4. Field management. After planting Dendrobium, moist air conditions should be maintained, and watering should be appropriate, but excessive watering must be strictly prevented, and water accumulation causing root rot must be avoided. No fertilization is needed when planting Dendrobium. Starting from the second year after planting, topdressing should be carried out 1-2 times per year. The first is bud-promoting fertilizer, applied around the Spring Equinox to Qingming; the second is warming fertilizer, applied around the Start of Winter. Use cake meal, bean dregs, cow dung, pig dung, fertile soil mixed with phosphate fertilizer and a small amount of nitrogen fertilizer, mix evenly, and then spread a thin layer around the roots. Because the root system of Dendrobium has a relatively poor ability to absorb nutrients, in order to promote its growth, during its growing period, every 1-2 months, foliar fertilization is often carried out with 2% superphosphate or 1% potassium sulfate. Regardless of the cultivation method used for Dendrobium, the time for applying fertilizer and water should be after the morning dew has dried, and application under the high temperature of the blazing sun is strictly prohibited, otherwise it will seriously affect the normal growth of Dendrobium. After planting, Dendrobium is weeded 2 times per year, the first from mid-March to early April, and the second during November. In the high-temperature summer season, weeding is not advisable, so as not to affect the normal growth of Dendrobium. Each spring before sprouting or when harvesting Dendrobium, part of the old branches and dead branches, as well as overly dense stems and branches, should be cut off to promote new bud growth. After Dendrobium has been planted for more than 5 years, the plants sprout abundantly, old roots die, the substrate rots, and pathogens infect, causing poor plant growth. Therefore, according to the growth situation, the clumps should be turned over, dead and decayed old roots removed, and division carried out for separate cultivation, to promote plant growth and increase yield and income.

5. Pest and disease control. The main diseases that usually occur during the growth and development of Dendrobium are: ① Black spot disease. This disease often occurs from March to May. Use 1:1:150 Bordeaux mixture or 1000-fold Duoling solution to prevent and control its development. ② Sooty mold. March to May is the main onset period of this disease. Use 50% carbendazim 1000-fold solution or 40% dimethoate emulsifiable concentrate 1500-fold solution for spray control 1-2 times. ③ Anthracnose. January to May is the main onset period of this disease. Use 50% carbendazim 1000-fold solution or 50% thiophanate-methyl 1000-fold solution for spraying, to prevent and control the infection of new plants by this disease. The main pests currently found are: ① Dendrobium scale insect. Late May is the peak hatching period for this pest, and 40% dimethoate emulsifiable concentrate 1000-fold solution or 1-3 degree lime sulfur mixture has better killing effect. For those that have formed shields but are few in number, the method of cutting off old branches and leaves and burning them centrally or crushing them to death can be used for control. ② Snails. Mix bran with trichlorfon and scatter it in places where the pests often move for poison bait trapping; spray pesticides such as trichlorfon and deltamethrin on the cultivation bed and surrounding environment, and quicklime can also be scattered.

6. Harvesting and primary processing. After 2-3 years of cultivation, harvesting can be done in all four seasons, but it is best to harvest before sprouting from the Start of Winter to Qingming. When harvesting, use scissors or a sickle to cut the old plants from the stem base, taking care to harvest old ones and leave tender ones, so that the remaining tender plants continue to grow, achieving the goal of planting once and benefiting for many years. Fresh Dendrobium is harvested without removing leaves and fibrous roots and used directly for medicinal purposes. Or remove fibrous roots and branches and leaves, and store in moist sand for later use. The traditional processing methods for dried Dendrobium are the water blanching method and the hot stir-frying method. ① Water blanching method. Remove the leaves and fibrous roots from fresh Dendrobium, soak in water for several days until the leaf sheath cuticle rots, then use a brush to scrub off the leaf sheath cuticle on the stems or use bran husks to rub off the cuticle. After drying in the air, bake, and after drying, bundle with dry rice straw and cover with a bamboo mat to make it airtight. The baking heat should not be too strong and should be even; when baked to 70-80% dry, rub once more and dry again, take out and spray a little boiling water, then pile up in order, cover well with a straw mat to make the color turn golden yellow, and then bake until completely dry. ② Hot stir-frying method. Place the fresh Dendrobium cleaned as above in a pot containing heated river sand, press the Dendrobium down with the hot sand, frequently turn it up and down, and when it makes a slight crackling sound and the leaf sheaths dry, crack, and curl up, immediately take it out and place it on a wooden washboard to rub repeatedly, to remove all remaining leaf sheaths, wash off the sand with water, dry in the hot sun, and after night dew, rub repeatedly again the next day; repeat this 2-3 times to make the color golden yellow, the texture compact, and dry it to obtain the product.