Key Points of Rapid Summer-Autumn Cultivation Techniques for Ceylon Spinach

Ceylon spinach (scientific name: Gynura cusimbua), also known as chan cai, luokui, tofu vegetable, or purple angle leaf, is a plant of the genus Gynura, a perennial tall herb, 1.5-2 m tall. Flowering and fruiting period is September-October. Ceylon spinach is eaten as seedlings, tender shoots, or tender leaves; its texture is tender and smooth, and its nutritional value is high. It can be used in soups, stir-fried, blanched, or served cold; it has a delicate fragrance and, when chewed, is as crisp and refreshing as eating wood ear, hence the name Ceylon spinach. It is commonly cultivated in both northern and southern regions; in the tropical regions of the south it can be grown as a perennial, while in the north it is mostly grown as an annual.

Morphological Characteristics of Ceylon Spinach Ceylon spinach is a perennial tall herb, 1.5-2 m tall. The stem is fleshy, woody at the base, 1.5-2 cm in diameter, prostrate in the lower half and erect in the upper part, with numerous corymbose branches, green or tinged with purple, with obvious grooves, hairless or more or less hairy in the upper part. Leaves are large, sessile or short-stalked; the leaf blade is obovate, oblong-elliptic, elliptic, or oblong-lanceolate, 10-30 cm long and 4-11 cm wide, with an acuminate apex, the base cuneately narrowed into a short petiole or sessile and expanded into a broad auricle clasping the stem, the margin irregularly sharply serrate, the tooth tips with small points, lateral veins 12-30 pairs, arcuately curved, green above, sometimes turning purple beneath, both surfaces hairless; the upper leaves gradually become smaller, oblong-lanceolate or lanceolate, with a long acuminate or caudate apex. Capitula are 10-12 mm in diameter, usually with 4-15 flowering stems, arranged at the branch tips in corymbose panicles; the inflorescence branches vary in length, the peduncle is slender, 1.5-3 cm long, with 2-3 filiform-linear bracts, covered with short pubescence. Involucral bracts are narrowly campanulate or cylindrical, 12-17 mm long and 8-12 mm wide, with 7-9 linear-filiform bracteoles at the base; the involucre is in 1 layer, 13-15 bracts, linear or linear-lanceolate, 13-15 mm long and 1-1.5 mm wide, with an acuminate apex, dry-membranous margins, and 3 distinct ribs on the back, hairless or nearly hairless. There are about 50 florets, orange-yellow, the corolla 11-13 mm long, the tube slender, 7-9 mm long, expanded above, the lobes triangular-ovate, the limb 3-4 mm long. Achenes are cylindrical, 4-4.5 mm long, brown, with 10 ribs, with fine hairs between the ribs. Pappus numerous, white, silky, 10-15 mm long, easily falling off. Flowering and fruiting period is September-October.

Because Ceylon spinach is heat-tolerant and grows rapidly, it is suitable for rapid cultivation in summer and autumn. Currently commonly used varieties include: red luokui, green-stem luokui, broad-leaf luokui, white-flower luokui, etc. According to the different parts harvested, it can be divided into non-trellised cultivation for harvesting tender shoots and trellised cultivation for harvesting tender leaves. Below we introduce the key points of rapid summer-autumn cultivation of Ceylon spinach.

Before sowing, apply 2500 kg of decomposed organic fertilizer and 450 kg of superphosphate per mu, deep plow, rake level, and spray 200 g per mu of no-deep-plowing soil conditioner to promote loosening and aeration of the deeper soil. Make level beds. Before sowing, first soak the seeds in warm water at 35°C for 1-2 days; for summer-autumn cultivation, there is no need to promote germination. For broadcast sowing, use 8 kg of seed per mu, with an effective standing seedling count of 30,000 plants per mu. 

After emergence, thin and then finalize the seedlings. For leaf harvesting, the plant and row spacing is 30-40 cm × 40-60 cm, with 1-5 plants per hole; for tender shoot harvesting, the plant and row spacing is 15-20 cm × 30-40 cm, with 1-3 plants per hole. 

After luokui emerges, keep the soil moist and water in a timely manner. After each harvest, promptly apply one topdressing of human and animal manure and urine, 500 kg per hectare, or 10 kg of urea; in the rainy season, drain promptly to prevent waterlogging. 

When harvesting tender shoots, when the seedlings are 30-35 cm tall, leave 3-4 leaves and cut the first shoot. Then select and retain 2 strong, vigorous lateral buds to become shoots, and remove the rest. After harvesting 2 rounds of shoots, again retain 2-4 strong lateral buds to become shoots, and remove the rest. During the vigorous growth period, 5-8 strong lateral buds may be selected and retained to become shoots. In the middle and late stages, remove flower buds at any time. At the end of the harvest period, 1-2 strong lateral buds may be retained to become shoots. 

For leaf-harvesting cultivation, trellises should be set up for the vines to climb; for the selected main vines, apart from the main vine, generally strong lateral buds at the base should be selected to become vines. When the main vines grow to the top of the trellis, pinch off the growing tip. After pinching, again select and retain strong lateral buds from the base of the main vines to become vines. 

40-50 days after sowing, harvest tender leaves; generally in the early stage, harvest once every 15-20 days; in the middle growth stage, every 10-15 days; in the late stage, every 10-17 days. When harvesting tender shoots, generally use a knife or scissors to cut, preferably at a length of 10-15 cm, harvesting once every 7-10 days. It is also possible to cut tender shoots in the early and late stages and harvest tender leaves in the middle stage. 

The disease that commonly occurs in Ceylon spinach is: brown spot disease, also known as fish-eye disease, red spot disease, snake-eye disease, sun spot, etc. In the early stage of occurrence, it can be controlled by spraying 600 times dilution of 72% Kelu wettable powder, or 1000 times dilution of 68.75% Yibao water-dispersible granules.