How to Grow Chinese Toon Seedlings? A Detailed Guide to the Planting Method

I. Propagation Methods

Chinese toon propagation is divided into two types: sowing and raising seedlings, and division propagation (also called root-tiller propagation).

1. Propagation by sowing

Because the germination rate of Chinese toon seeds is relatively low, before sowing the seeds should be soaked with added (Gao Xin Zhi Mo) in warm water at 30—35℃ for 24 hours, then taken out and placed at 25℃ to germinate. Sow when the radicle protrudes to the size of a grain of rice (the minimum soil temperature at sowing is about 5℃); in the Shanghai area this is generally in early to mid-March. After emergence, thin the seedlings when they have 2—3 true leaves, and set the final spacing when they have 4—5 true leaves, with row spacing of 25x15 cm.

2. Propagation by division

In early spring, dig up young seedlings from the roots of mature plants and plant them in the seedbed; when the following year the seedlings have grown to about 2 m, transplant them to their final position. A root-cutting tiller method may also be used: in late winter and early spring, dig a circular trench 60 cm deep around a mature tree, cut off some lateral roots, then fill the trench level again. Because Chinese toon roots readily produce adventitious roots, new shoots sprout from the cut root ends and can be transplanted the following year. After transplanting, spray with Gao Xin Zhi Mo, which can effectively prevent above-ground moisture from evaporating, stop the seedling from transpiring water, isolate pests and diseases, and shorten the seedling recovery period.

After the Chinese toon seedlings have been raised, they are all transplanted in early spring before bud break. For large-scale Chinese toon plantations, the row spacing is 7x 5 m. When planted along canals or behind houses, they are in single rows with a plant spacing of about 5 m. After transplanting, water 2—3 times to increase the survival rate.

3. Harvesting Tips

Chinese toon grown by ordinary cultivation and by dwarfed high-density cultivation generally sprouts before Qingming, and around Guyu the terminal buds can be picked. This first picking is called the first-crop toon sprout; it is not only plump and tender but also richly fragrant, of top quality. Afterwards, according to growth conditions, pick the second crop after an interval of 15—20 days. Newly planted Chinese toon can be harvested at most 2 times; after 3 years it can be harvested 2—3 times each year, and the yield increases accordingly. As for protected cultivation, by adding heat it can also be harvested in winter; if not heated, the tree buds can be supplied early in spring.

II. Dwarfed Cultivation

1. Choose high-quality seeds

Choose new seeds from the current year. The seeds should be plump, fresh in color, reddish-yellow, with yellow-white kernels, a purity of over 98%, and a germination rate of over 40%.

2. Keep warm and germinate

To achieve uniform emergence, germination treatment is needed. The method is: use warm water at 40℃, soak the seeds for about 5 minutes while stirring constantly, then place them in water at 20℃~30℃ and soak for 24 hours. After the seeds have absorbed enough water, take them out, drain off excess water, put them on a clean reed mat spread 3 cm thick, cover with a clean cloth, and keep them at 20℃~25℃ with moisture to germinate. During germination, turn the seeds 1~2 times a day and rinse them 2~3 times with clean water at about 25℃, draining off excess water. When 30% of the seeds have sprouted, they can be sown.

3. Sow at the right time

Choose flat land with ample light, good drainage, sandy soil and fertile soil as the seedling bed; apply fertilizer while preparing the land, spread it evenly and dig it through. In a 1 m wide bed, open furrows at 30 cm row spacing, with furrow width 5~6 cm and furrow depth 5 cm; sow the germinated seeds evenly and cover with 2 cm of soil.

4. Seedling management

Seedlings emerge about 7 days after sowing. Before emergence, strictly control watering to prevent soil crusting from affecting emergence. When the young seedlings have emerged and grown 4~6 true leaves, thin and set the seedlings. Water before setting the seedlings, then set them at a plant spacing of 20 cm. When the plants are about 50 cm tall, carry out dwarfing treatment of the seedlings. Use 15% paclobutrazol at 200~400 times dilution, spraying once every 10~15 days for 2~3 consecutive sprays, which can control excessive growth, promote dwarfing of the seedlings, and increase matter accumulation. Combining paclobutrazol treatment with pinching can increase the number of branches.

III. Management After Transplanting

1. Land preparation and fertilization

Chinese toon grown in solar greenhouses must be given sufficient base fertilizer. Apply no less than 5000 kg of high-quality farmyard manure per mu, no less than 100 kg of superphosphate, and 25 kg of urea; spread evenly and plow deeply. Then prepare the beds and plant the seedlings; generally the bed width is 80~100 cm

2. Transplanting density

The transplanting density should be about 30,000 plants per mu, with a plant spacing of 15 cm and a row spacing of 15 cm.

3. Careful management

Temperature management: for the first few days no heating is needed; keep the temperature at 1℃~5℃ to help the seedlings recover. 8~10 days after transplanting, cover the greenhouse with straw mats, uncover them during the day and cover them well at night. Keep the temperature inside the shed at 18℃~24℃ during the day and 12℃~14℃ at night. Under these conditions, Chinese toon sprouts can grow in 40~50 days.

Hormone regulation: after transplanting and seedling recovery, treat with Chouzhibao by applying the medicine to fixed points on the upper 4~5 dormant buds of the Chinese toon seedlings; 1 gram of medicine coats 100~120 buds. Applying the medicine can make the buds plump, the young shoots robust, and can increase yield by 10%~20%.

Humidity regulation: newly planted Chinese toon seedlings in the greenhouse should maintain relatively high humidity. After transplanting, water thoroughly, then water lightly as conditions require; the relative air humidity should be kept at about 85%. During the growth period after sprouting, a relative humidity of about 70% is best.

Light regulation: solar greenhouse Chinese toon production requires good light to promote growth. Use drip-free film and keep the greenhouse film clean.

4. Harvesting toon sprouts

Under suitable temperature conditions (18℃~24℃ during the day, 12℃~14℃ at night), Chinese toon sprouts grow quickly, turn purplish-red, and have a strong fragrance. 40~50 days after the greenhouse is covered with straw mats, begin harvesting when the Chinese toon sprouts have grown to 15~20 cm and are well colored. The first crop of toon sprouts should be harvested by picking the terminal bud growing in a cluster on the sprout stalk; when picking, leave a little of the sprout stalk and take the terminal bud, so that the base of the remaining sprout stalk continues to produce leaves. Harvesting is best done in the morning and evening. In the greenhouse, Chinese toon sprouts can be harvested once every 7~10 days, for a total of 4~5 harvests; after each harvest, fertilize and water. 

IV. Planting Techniques

1. Temperature regulation

According to observation, when the shed temperature is about 25℃, the tender shoots can grow 3—4 cm in 24 hours; at 15℃, they grow only 1 cm; when the shed temperature exceeds 35℃, it affects the coloring and quality of the toon sprouts. 10—15 days after covering with film is the seedling recovery period, and efforts should be made to raise the air temperature; during the day the shed temperature can be about 30℃. After more than a month of natural light and temperature accumulation, once the buds have sprouted, control the daytime temperature at 25—30℃ and the nighttime temperature at 13—17℃; during the harvest period the temperature should be 18—25℃. As conditions require, cover with straw mats and paper quilts to increase or preserve warmth.

2. Humidity regulation

Seedlings planted in the greenhouse have a poor ability to absorb water through the roots, so at first relatively high soil humidity and air humidity should be maintained. After planting, water thoroughly, then water lightly as conditions require. Keep the relative air humidity above 85%; on sunny days also spray water on the seedlings to prevent water loss and drying out. After sprouting, a relative air humidity of 70% is suitable; if humidity is too high, not only is sprouting delayed, but the fragrance is greatly reduced, so ventilation should be provided promptly to remove moisture.

3. Light regulation

Chinese toon likes light, so drip-free film should be used as much as possible; uncover the straw mats and paper quilts promptly during the day, and frequently clean debris off the film to increase light. If the light is too strong, cover appropriately with grass for shade.

4. Pinching to promote branching

When harvesting the second crop of Chinese toon, remove the top at the same time to set the trunk height (pinch at 40 cm above the ground). After setting the trunk height, spray 15% paclobutrazol solution at a concentration of 200—500ppm to control apical dominance, promote rapid branch growth, and achieve dwarfed cultivation. Thereafter, according to the development of the tree shape, pinch and prune side shoots promptly to ensure the crown has many branches and produces many toon sprouts, achieving high yield and quality.

5. Water and fertilizer management

Chinese toon is a fast-growing woody vegetable with modest water requirements; among fertilizers it has a relatively high demand for potassium fertilizer. For every 300 sq m of greenhouse, the base fertilizer requires about 2500 kg of fully decomposed high-quality farmyard manure, 75—150 kg of plant ash or 3—6 kg of monopotassium phosphate, and 3—6 kg of diammonium carbonate. After each harvest, apply an appropriate amount of topdressing and water according to soil fertility, the growth of the Chinese toon, and leaf color.

6. Bagging with light-blocking film

After Guyu, once the soil temperature is above 18℃, the greenhouse film can be removed to let the saplings grow naturally. Afterwards, although the saplings develop quickly, they tend to age, so black-and-red two-layer, two-color polyethylene film bags should be prepared early. When the Chinese toon sprouts have grown to 5 cm, the light-blocking film bags can be put on. This can both increase yield and ensure the toon sprouts do not age. When the toon sprouts have grown to 15 cm, pick them together with the bag, then remove the bag for sale; this kind of film bag can be reused many times.