ROSELLE PLANT (Hibiscus sabdariffa) By Hellen Omondi Introduction The roselle plant is a member of the hibiscus family, Malvaceae often referred to as "Ribena plant”. The shrub can grow up to 2.25m high and produces white to yellow flowers which sit on a stout fleshy red coloured calyx. In Kenya, it is an emerging herbal crop of economic importance the herb and is mainly grown in Western and Nyanza regions. It is produced without the use of chemical fertilizers and insecticides. Roselle is mainly grown mainly for the calyx which is high in Vitamin C and dietary fibre. They are also a useful source of calcium, iron, vitamins B2 and B3. The drink possesses anti-hypertensive, diuretic and mild laxative properties, and contains abundant amounts of natural antioxidants such as vitamin C and anthocyanins. Uses in Kenya · The calyx is used to prepare herbal drinks, beverages, jams and jellies, paste, sweets, syrup, ice cream, flavouring and for wine preparation; its manufacturing residues can also produce vinegar of very good quality. Roselle plant The young leaves and tender stems of roselle are eaten raw in salads or cooked as vegetables alone or in combination with other vegetables, meat or fish. They are also added to curries as seasoning. Other uses Roselle seeds contain 17% oil. The seed oil is used in soap and cosmetics industries. In addition, the seed oil is extracted and used for cooking and as an ingredient in paints · The plant can also be used as an alternative cut-flower material for flower arrangements, after the removal of its leaves. · The stems of the roselle plant also produce fibre that can be used as a substitute for jute in making bugs · The seeds are roasted as snacks or ground into meal to make cakes. Prospects for Roselle In Kenya Roselle is multipurpose crop which can provide food and cash income as a vegetables and processing of domestic and industrial products. Dried calyces have high market potential for both export and local market. Demand for roselle products is likely to increase as a result of the rising interest in natural herbal products that are caffeine free like the roselle tea. Currently, Malaysia supplies much of the Roselle raw material globally. In Kenya the herbal tea and beverage are sold in the super markets and other shops with specialized herbal products. Variety There are two main types of cultivated roselle Sabdariffa with a bushy, strongly branching habit Altissima Wester with taller, usually unbranched habit. This variety is grown for its fibre, and not common in Africa. Ecological Requirements Altitude An altitude 900 m above sea level is suitable for production Rainfall Annual rainfall between 400 -500 mm is required throughout the growing season. Heavy rains or high humidity during the harvest time and drying can downgrade the quality of the calyces and reduce the yield. Temperature The temperature range within which the plant performs well is between 18 -35ºC, with an optimum of 25ºC. Growth of the plant ceases at 14ºC. Soil Roselle plants prefer well-drained, fertile soils with high organic matter and pH of 4.5 - 8.0. Plants can tolerate floods and heavy winds. Photoperiod Roselle is a short-day plant that is very sensitive to the photoperiod. In the first 4-5 months of its growth, Roselle requires a daily light phase of 13hours. Flowers do not develop if there is more than 13 hours of sunlight in a day, while flowering is excellent when daylight is shorter than 12 hours. Planning Production Ensure the area meets the production requirements Get clean seeds from a recommended source Plan for marketing of the produce. The dried calyx is sold to companies that make Herbal products: herbal teas, fruit based products: beverages, soft drinks, jam and wines. Propagation and production systems The roselle plant can easily be raised from seeds or stem-cuttings. The seeds germinate easily so can be planted directly in the field Seedlings can also be raised in the nursery, and transplant into the field after about 4 weeks. Plant can be planted outdoors on the ground or in containers as long as the plant receives direct sunshine for at least 6 hours daily. It is also grown as a hedge crop, or intercropped with other crops. Commercially it is grown as a pure stand crop. Roselle is can be intercropped with other crops such as pearl millet, sorghum, groundnut, sweet potato and cowpea. Land Preparation Roselle is a deep rooted crop and hence it requires deep ploughing. Seeds rate is 6-8 kg/ha and. Planting Direct planting is done in the field at beginning of rainy season. Plant 2 seeds per hole at about 2.5 cm depth Spacing The spacing of 80–100 cm within the rows and 60–80 cm apart between the plants is recommended. Manure Manure -500-1000kgs per acre can be applied during planting Weeding Timely weeding should be done to reduce pest damage and competition with the plants Diseases and Pests Major diseases of hibiscus are stem rot and root rot. Prevention techniques include monitoring the water content in an irrigated field, and avoiding the planting of other crops that are also prone to these diseases. Insect damage is minor; pests include stem borer, flea beetles, cotton bollworm and cutworm. Mealy bugs and leafhoppers are minor concerns, as is the cotton stainer. Use of natural enemies is recommended. Harvesting · The calyces are ready for harvesting 20 days after flowering. The inner seedpod should be still green when fruit is picked, although fruit can remain on the plant until the pods mature and seeds disperse. Harvesting method · Calyces are harvested manually 2–3 weeks after flowering, usually 4–6 months after sowing, before the fruit has dried and opened up. Regular picking prolongs flowering. · Young shoots and leaves are harvested when required. · The calyx is separated from the seed pod by hand, or by pushing a sharp edged metal tool through the fleshy tissue of the calyx separating it from the seed pod. Care should be taken during harvesting to avoid contamination by extraneous material. · The more time the capsule remains on the plant after the seeds begin to ripen, the more susceptible the calyx is to sores, sun cracking, and general deterioration in quality. (When harvested for fibre, stems are cut before flowering, 4–5 months after planting. Fibre quality declines rapidly after the start of flowering). Yield · Fresh calyx yields range from 4–6.5 t/ha, or about 800–1200 kg/ha when dried to 12% moisture content. · A single roselle plant may yield as many as 250 calyces, or 1–1.5 kg fresh weight depending on environmental conditions and management. · Yield for leaves, is about 10 t/ha. Drying Roselle withers rapidly when fresh and hence cannot be kept for long time or exported over long distances. In Kenya roselle calyces are air dried prior to marketing. It is recommended to dry in the shade with adequate ventilation since drying in the sun can lead to reduced quality. Plastic sheets are placed on the ground to avoid contamination with soil, which also strongly reduces the value. If heat drying methods are used, care must be taken so that the temperature does not exceed 430C. High temperatures degrade the phyto-chemicals Challenges in production The price is determined by quality of calyx hence care should be taken during harvesting and when drying the calyces to avoid contamination by extraneous material. Intensive labour is required for harvesting which increases the total cost of production. Advice to growers Roselle can be grown as a supplementary crop on the farm to boost income; it is drought tolerant and requires minimal attention and inputs once established. Farmers are advised to grow and market the produce collectively in order to get better prices. Value addition of the produce at farm level is also encouraged in order to get high returns.