How to Grow Roselle? A Detailed Guide to Planting Methods

Roselle, a Chinese medicine name. It is the root and seed of the mallow family plant roselle. It has been introduced and cultivated in Fujian, Taiwan, China, Guangdong, Hainan, Guangxi and southern Yunnan in our country. So, how do you grow roselle?

1. How to grow roselle?

1. Soil requirements

Roselle is a plant that fears waterlogging but not drought. It is best to plant it in sandy loam that faces the sun, has deep soil and drains well. Apply 1000-1500 kg of farmyard manure per mu.

2. Planting density

According to the soil fertility, the plant and row spacing: 0.6-0.8 cm, and it is best to sow 1300-1500 holes per mu.

3. Sowing time

Soak the seeds for 12 hours before sowing. Sowing from mid-to-late April to early May is more suitable. For dibbling, put 3-4 seeds in each hole; when using nutrient pot seedling raising and transplanting, transplant in time when the seedlings are 12-15 cm tall.

4. Field management

(1) Timely pest control: seedlings emerge 5-7 days after sowing. Spray with 50 ml per mu of 2.5% lambda-cyhalothrin to control pests. Pesticides must be sprayed before flowering. Spraying pesticides is strictly prohibited during the flowering period, so as to avoid pesticide residue remaining in the calyx and affecting product quantity.

(2) Timely thinning, final thinning and pinching: when the seedlings grow to 10-15 cm, thinning should be carried out. Thin out weak and diseased seedlings, keep only one healthy seedling in each hole, and pull out the rest to fill gaps. Thinning should not be too late, otherwise it will affect the growth of the seedlings. When the seedlings are 80 cm tall, pinching should be carried out to promote strong branches, more flowers and plump calyces.

(3) Fertilizing and irrigation: roselle does not need large amounts of water and fertilizer, but land with poor fertility should be properly topdressed. Apply 20 kg of compound fertilizer, 8 kg of urea and 5 kg of zinc fertilizer per mu by watering to promote seedling growth; before flowering, apply 30 kg of compound fertilizer and 20 kg of potassium sulfate per mu to meet the needs of flowering.

(4) Cultivation and weeding, draining waterlogged fields: when the plant height is 30 cm, combine topdressing with earthing up, and carry out 2-3 cultivations at the right time. In summer, because there is a lot of rain and weeds grow thickly, manual weeding should be carried out to avoid competing with roselle for fertilizer and water. During the rainy season, pay attention to digging ditches to drain waterlogging and prevent seedling death and root rot.

5. Harvesting and drying

Roselle is mainly harvested for its calyces. In mid-to-late October, when the seeds inside the flower bracts become hard or brown, cut off the fruiting branches and remove the calyx together with the fruit. After they shrink from water loss, remove the calyx. When removing the calyx, a thin metal tube can be used to push out the round fruit. The calyx must be kept intact and must not be split apart and peeled off. Roselle is acidic and very easy to mold, so it must be dried in time.