Planting season and methods for Platycodon grandiflorus (balloon flower): spring sowing and winter sowing are both options

AbstractPlatycodon grandiflorus can be spring-sown in March-April, or winter-sown from November to January of the following year. For spring sowing, the seeds need to be hot-water treated, and they can be sown once the seeds begin to sprout. For planting Platycodon grandiflorus, winter sowing is more suitable: first mix fine sandy soil and seeds in a certain ratio, then spread it evenly over the seedbed surface by broadcast sowing.

I. Planting season for Platycodon grandiflorus

1. Spring sowing

(1) Carry out in March-April; when sowing, the seeds need hot-water treatment, soaking the seeds in 30°C warm water for 8 hours.

(2) Then wrap the seeds in a wet cloth and place them in a 25-30°C location, cover them with a wet hemp piece on top for germination, and rinse with warm water once a day.

(3) After about 5 days, once the seeds begin to sprout, they can be sown; after sowing, the soil moisture must be kept up long-term, and seedlings will emerge after about 15 days.

2. Winter sowing

(1) Carry out from November to January of the following year; for Platycodon grandiflorus, winter sowing is preferable, using the broadcast sowing method.

(2) Mix fine sandy soil with the seeds; the ratio of seeds to soil is 0.3:1; after mixing, spread evenly over the seedbed surface.

(3) Sweep the seedbed surface with a broom until the seeds on the surface can no longer be seen; seedlings will emerge the following spring.

II. Planting methods for Platycodon grandiflorus

1. Site selection and land preparation

(1) Platycodon grandiflorus is a perennial herbaceous plant and a deep-rooted crop; when selecting a site, try to choose sloping land or open flat areas with fertile soil, easy rooting and good drainage.

(2) Before winter arrives, the soil can be deep-plowed and left to mature.

(3) In the spring of the following year, prepare the land: apply about 2500-3000 kg of farmyard manure per mu, about 25 kg of potassium sulfate, about 25 kg of urea, about 35-40 kg of diammonium phosphate, and about 100 kg of superphosphate as base fertilizer, then level the land with a harrow.

(4) Finally, make beds about 6 cm high and 1.3-1.7 m wide.

2. Variety selection

For the Platycodon grandiflorus variety, generally choose the purple-flowered Platycodon grandiflorus, which has higher medicinal properties than other varieties.

3. Standardized sowing

(1) Platycodon grandiflorus is generally sown by broadcast sowing, using 2.5 kg of seed per mu.

(2) When sowing, mix the Platycodon grandiflorus seeds evenly at a ratio of 0.3 kg of seeds to one basin of fine sandy soil, then spread over the seedbed and press lightly so the seeds make full contact with the seedbed surface.

(3) By the spring of the following year, the seedlings emerge early. When spring sowing, artificially treating the seeds will make the resulting seedlings uniform; you can also choose the method of covering with grass after sowing to retain moisture.

(4) The grass-covering moisture-retention method is to soak all the seeds in about 30°C warm water for eight hours, then after soaking wrap them in a water-moistened cotton cloth, place them in a suitable 25-30°C location, and cover with a layer of wet hemp piece on top for germination.

(5) Rinse continuously with warm water for five days. The sowing method for winter sowing is the same as for spring sowing; be careful to maintain soil moisture long-term, and seedlings can emerge in about half a month.

4. Field management

① Thinning and filling in seedlings

The Platycodon grandiflorus beds should be appropriately thinned and set; when seedlings are 2 cm, thin them to a spacing of 10-13 cm, and when they are 3-4 cm, set the seedlings. When filling in seedlings, do not forget to transplant with soil, and do it at the same time as thinning.

② Cultivation and weeding

Cultivation and weeding can be done at the time of thinning; choose to loosen the soil after watering when the soil is slightly moist, to remove weeds for the seedlings. Once the Platycodon grandiflorus plants have grown and developed, cultivation and weeding are no longer needed.

③ Fertilization

Fertilize the seedlings after thinning, setting and irrigation; fertilization can promote the growth and development of the seedlings. When the seedlings reach about 6-7 cm in height, apply 20 kg of superphosphate and 10 kg of urea per mu.

④ Topping

When the seedlings grow a bit taller, to 10 cm in height, carry out topping. Necessary topping can improve seed quality, and affects the number of seeds in the fruit and seed plumpness.

⑤ Earthing up

After fertilizing and topping the seedlings, remove excess weeds and earth up, which can prevent the plants from being blown over or torn apart when the wind is too strong.

⑥ Bud removal

At full bloom, spray once with 1000 ml of ethephon to remove excess flower buds. Compared with no spraying, the yield increases by 45%; removing buds and picking flowers can increase the yield of Platycodon grandiflorus.

5. Pest and disease control

① Fusarium wilt

In the early stage of Fusarium wilt, the lower root part and stem base turn brown and become dry and sunken. In the early stage of the disease, spray 50% carbendazim 800-1000 times dilution, or 50% thiophanate-methyl 1000 times dilution for control.

② Violet root rot

In Platycodon grandiflorus affected by violet root rot, the root epidermis turns red and is covered with mycelium; in severe cases the color gradually turns reddish-brown or purplish-brown, and the mycelium gradually transforms into a sclerotium the size of a mung bean. In the late stage of the disease, the plant rots and dies, causing severe yield reduction.

③ Ring rot and leaf spot

Ring rot and leaf spot mainly damage the leaves; they can be controlled by spraying 50% carbendazim 1000 times dilution or 1:100 Bordeaux mixture.

④ Pests

Mainly cutworms, false wireworms, mole crickets, aphids and other pests, which eat the roots, stems and seedlings. (Control methods: for aphids, spray 40% dimethoate 500 times dilution; for underground pests, drench with 50% phoxim 500 times dilution or 90% trichlorfon 800 times dilution, or make into poisoned bait and feed.)