A Detailed Guide to the Propagation Methods and Cultivation Techniques of Leafy Goji (Vegetable Goji)
Goji (Lycium chinense) is a perennial small shrub of the genus Lycium in the Solanaceae family, distributed throughout the country. The plant loves light, tolerates cold and heat, tolerates drought and dislikes moisture; its suitable growing temperature is 15-20°C, growth is slow at 10°C, and growth is poor above 25°C. At present, the northern regions of China such as Ningxia, Gansu, Shaanxi and Shandong mainly grow it for fruit, while the southern regions such as Guangdong and Shanghai grow it for use as a vegetable.
Leafy goji has a sweet-bitter taste and a distinctive flavor; it is not only nutritious but also of high medicinal value. Every 100 g of goji greens contains 5.8 g protein, 1 g fat, 61 g carbohydrate, 3.9 mg carotene, 3 mg vitamin E, 155 mg calcium, 67 mg phosphorus and 3.4 mg iron. When soil fertility and moisture are sufficient, the stems and leaves of goji are tender and fresh, with little fiber and good taste.
Leafy goji mainly has two cultivated varieties: large-leaf goji and fine-leaf goji. Large-leaf goji has broad, ovate leaves, a delicate fragrance, and a mildly sweet-bitter taste with a distinctive flavor; it is almost thornless. Fine-leaf goji has lanceolate leaves, a stronger fragrance and bitter taste, and thorns in the leaf axils. Most of the goji varieties planted in the Shanghai area are large-leaf goji, mostly grown as annual crops under protected cultivation, with a small amount grown in the open field as a perennial crop; it can also be used as a hedge or for soil stabilization along riverbanks.
1 Propagation Methods
The propagation methods of goji include seed propagation, cutting propagation, division propagation, layering propagation and tissue culture propagation. Among these, seed propagation and cutting propagation have the advantages of fast speed and a high survival rate, and are highly practical in production.
1.1 Seed propagation: Soak the seeds, mix them evenly with moist fine sand, keep them moist to promote germination, and sow once half of the seeds have sprouted white. The best sowing time is March to April, and under protected cultivation it can be moved up to February. Before sowing, deep-plow the seedbed and apply sufficient base fertilizer; after building the beds, open shallow furrows at a row spacing of about 40 cm and sow in rows. When sowing, evenly scatter the mixed seeds and fine sand into the furrows, cover with soil and press firm, and after watering cover with plastic film to retain moisture. About 1 week after sowing, the goji seedlings begin to emerge one after another; after emergence, the film should be removed, and water should be sprayed to retain moisture. When the seedlings are about 5 cm tall, thin them to a plant spacing of 3-6 cm; during thinning, take care to pull out inferior seedlings, promptly remove weeds, and water and fertilize.
1.2 Cutting propagation: In spring and autumn, select robust, lignified 1-2 year old branches from superior individual plants, cut them into cuttings about 10 cm long with 2-3 buds remaining, soak their bases in a 300 mg/L IBA solution for 20 min (minutes) and then insert them for rooting; the insertion depth is about 1/3-1/2 of the cutting, and the rooting medium is a 2:1 mixture of garden soil and vermiculite. Before cuttings are inserted, it is best to sterilize the medium first; whether raising seedlings in containers or in seedbeds, the medium thickness should be more than 10 cm to facilitate rooting and sprouting of the cuttings. After insertion, water thoroughly and cover tightly with nylon film; after 2 weeks the cuttings begin to root and sprout. Trials have found that cuttings treated with rooting agent can reach a rooting rate of 100%. About 3 weeks after insertion, the roots and new shoots of the goji have grown well and the plants can be transplanted.
2 Cultivation Techniques
2.1 Field planting: In general, both seedling-grown and cutting-grown goji plants can be planted in the same year they are propagated. Seedling-grown plants take slightly longer to raise and grow more slowly in the early stage than cutting-grown plants, so in production seedling-grown plants can also be planted in the spring of the second year. Leafy goji is suitable for wide-row, dense planting in spring or autumn, with a row spacing of 30 cm and a plant spacing of 10-15 cm. Before transplanting, apply fertilizer well and remove old leaves and dead branches. When transplanting, carry soil with the plants as much as possible and damage the roots as little as possible to help the seedlings survive. Under general conditions, goji seedlings with a well-developed root system can reach a transplanting survival rate of 100%. About 1 month after field planting, cutting-grown goji plants can be harvested for tender leaves and tender shoots.
2.2 Fertilizer and water management: The yield and quality of leafy goji are greatly affected by fertilizer and water. In production, fertilizer and water management should be strengthened according to the growth characteristics of goji to increase its yield and tenderness. This plant needs a lot of fertilizer during the growing period and requires continuous supplementation of nitrogen, phosphorus and potassium. After the goji seedlings develop new roots and new shoots, apply light topdressing in a timely manner. In addition to manure water, a foliar spray of 0.2% urea plus 0.3% potassium dihydrogen phosphate can also be applied once every 15 d (days). In dry seasons, pay attention to irrigation to keep the soil moist.
2.3 Pruning and trimming: During the growth of goji seedlings, attention should be paid to timely pest and disease control and weeding. In the Shanghai area, goji has relatively few pests and diseases; the main pest is aphids. If aphids occur severely, 40% dimethoate 1000-fold solution or 50% pirimicarb 2000-fold solution can be used for control. Weeds in the goji field should be pulled out promptly so they do not compete with the goji for nutrients. In the later stage of goji growth, the plants should be heavily pruned, maintaining a height of about 50 cm. By pruning the plants, lateral buds and latent buds can be forced to sprout, forming clump-like, multi-stemmed dwarfed plants, so that the tender tips are concentrated on one horizontal plane, making harvesting easier, and the tender stems are thick, the tender leaves large, and the quality excellent.
3 Development and Utilization Value
3.1 Solving the supply shortage in the vegetable off-season and enriching the variety of products: Leafy goji can clear heat and detoxify, brighten the eyes and clear the liver, and has anti-aging effects; it is a very good health-care vegetable. The production and supply of leafy goji can ease the contradiction between market supply and demand and has a positive effect. In the process of adjusting the structure of the planting industry in suburban areas, developing and utilizing leafy goji with its natural flavor is of great significance for increasing farmers' income and promoting the sustainable development of agriculture and forestry.
3.2 Leafy goji has strong stress resistance and is pollution-free: Goji was originally a wild vegetable; it tolerates poor soil and has strong stress resistance, and during its growth it suffers relatively little damage from pests and diseases. Leafy goji has a special delicate fragrance and strong resistance to stress, pests and diseases, and relatively little pesticide is applied in production, which plays a positive role in producing pollution-free vegetables and green food and safeguarding the public's food safety.
3.3 Low planting cost and high output value: Artificial cultivation and management of goji is simple; it can be planted in front of and behind farmers' houses, by riversides, or as a fence, and it can be harvested over the long term without special cultivation. If grown under protected cultivation, it can be produced and harvested year-round, achieving a higher output value.
3.4 Greening courtyards and beautifying the environment: Perennially cultivated goji, besides being used as a vegetable, also has a certain ornamental value. Goji has a fairly long ornamental period each year with green leaves, white flowers and red fruits, and has the effect of greening courtyards and beautifying the environment. In the past, people often planted goji in front of and behind their houses to green their courtyards; in recent years, some residents have also grown goji as bonsai on balconies, so it can be used both as a vegetable and for ornament, achieving two goals at once.