ROSELLE PLANT PRODUCTION

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

1. Sabdariffa with a bushy, strongly branching habit
2. 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.

TREE TOMATO (TAMARILLO)

By Hellen Omondi

Introduction

Tree tomato also known as Tamarillo is an egg-shaped edible fruit. The fruit contains high levels of fiber, vitamin A, B, C E and K and minerals, specifically iron, calcium, magnesium, potassium, phosphorous and is low in calories. It is an important source of pectin, carotene, and protein. Vitamin C, E and B-carotene (pro-vitamin A) are regarded as major nutritional antioxidants.

Utilization: The tree tomato flesh can be added to stews to make unique flavour. Fruit can be eaten fresh, cooked, made into jam chutneys or blended with other fruit juices e.g. orange juice to make refreshing juice or added to vegetable salads. The yellow variety is preferred for processing. The fruits should not be cut on wooden or other permeable surface as the juice will make an indelible mark. The fruits are high in pectin and therefore have good properties for preserves. The unripe fruit contains high level of tannin, thus bitterness.

Potential for production

There is high demand for the fruit especially in the urban market in hotels, supermarkets, local markets and with food vendors. Consumers are increasingly becoming aware of the nutritional and medicinal properties of the fruit hence the current supply cannot meet the demand due to limited production at commercial level within the country. The fruit can be grown in a wide range of climatic zones, it requires minimal input and is easy to manage once established.

Varieties: The colour of fruits varies from yellow and orange to red and almost purple. Sometimes they have dark, longitudinal stripes. Red fruits are more acidic, yellow and orange fruits are sweeter. Some varieties grown include: Ecuadorian orange, Gold mine, Inca gold, Red oratia , Rothame, Ruby red,  Solid Gold, Yellow.

Ecological Requirement

Altitude: The favourable production altitude in Kenya is 1000-2000m above sea level. However it can be grown up to 3000m above sea level. The fruit is slow to ripen in higher altitudes.

Rainfall: It requires rainfall 1200 - 2100 mm and cannot tolerate drought.  

Soils: Tamarillos requires well drained fertile soils that are rich in organic matter. The tree does not tolerate water logging because of the shallow root system. Soil pH of 5-8.5 are suitable for production.

Temperatures: Tamarillos prefer warm conditions as long as the plants are also provided with sufficient moisture. Temperatures should be above 10°C throughout the year. Persistent heavy frosts can kill even well-established trees.

Planning for production

• Selection of suitable site with required condition
• Selection of species depending on market requirement
• Organizing for planting material from a registered nursery

Note: The area under production should be set aside and expanded gradually so that production is increased according to market demand.

Tree tomato can be grown in the open field and also in the green house.

Land Preparation

Land should be prepared to a fine tilth and manure incorporated into the soil. This reduces or eliminates the need to apply fertilizer. In poorly drained soils ridges prepare for planting.

Propagation: Seeds and cuttings may be used for propagation.

Seeds: Seeds produce high-branched, erect tree. The tree does not always come true to type from seed, but is possible if seed is taken from red fruits with black seed pulp or yellow fruits with yellow seed pulp. Seed should be separated from pulp, washed and dried in the shade. Germination is accelerated by placing washed and dried seed in a freezer for 24 hours before planting out. Seeds- produce a high–branched erect tree ideal for sheltered locations; seeds germinate in 3-5 weeks.

Cuttings: Cuttings develop into a shorter, bushy plant with low–lying branches suitable for exposed windy sites. Cuttings should be from 1-2 years-old wood, 10-30 mm thick and 45-100 cm long.

Planting: The spacing in the field varies depending on the management practices, soil fertility and environmental conditions. The spacing is 2.5 -3 m apart between plants and 3 m between the row or 1.0-1.5m between plants and 4.5-5.0m between rows. Closer spacing is recommended in windy unprotected locations.

Manure and Fertilizer

A compound fertilizer such as NPK may be applied at planting time if necessary; however a good supply of compost is normally adequate.

Wind break: Tree tomato is fragile and is shallow rooted hence requires protection from wind because branches can easily break. Staking can be done to prevent swaying and to minimize root disturbance.

Pruning: The tree should be pruned back the first year after planting to a height of 0.9-1.2 m to encourage branching. Pruning helps to control fruit size, plant size and harvesting. If timed properly pruning can extend the total bearing period. Yearly pruning is therefore recommended to eliminate old branches that have already fruited because fruits are normally produced on new growth. Light pruning leads to medium sized while heavy pruning leads to large sized fruits. Basal shoots should be removed. In the green house pruning prevents excessive vegetative growth.

Weeding

Tamarillo is shallow rooted hence care should be taken when weeding the plant to avoid damaging the roots. Deep cultivation around the plants should also be avoided

Irrigation

The plant cannot tolerate prolonged drought and should have sufficient water during dry periods.  Supplement irrigate during dry periods especially at peak growth. Mulching is very beneficial in conserving moisture and also suppressing weeds.

Pests and Diseases

The plant belongs to solanaceae family and is related to potatoes, tomatoes, brinjals. These tend to suffer from the same pests and diseases, however tree tomatoes are generally pest and disease tolerant but occasional attacks of green aphids thrips and red spider mites and fruits flies.

The principal disease is powdery mildew which may cause serious defoliation if not controlled. Other diseases during growth include potato virus, cucumber mosaic virus and downy mildew. The fungal diseases (powdery mildew, downy mildew) can be controlled using suitable fungicides. Viral diseases can be prevented by controlling vectors e.g. aphids and fields sited away from host plants such as cucumber, potatoes

Harvesting

Tree tomatoes are ready to harvest when they develop red or yellow colour. The tree is a fast-growing, starts bearing fruits from 1.5-2 years after planting and bears fruits all year round. Fruiting should be discouraged at one year since this retards growth. Peak production is reached after 4 years and it continues for 5-6 years with good management.  The economical life span of the tree is about 11-12 years.

Yields: The average yield is15-20 kg per tree annually or 15-17 tons per hectare.

Storage: At room temperature the fruit can be stored for about 1 week, but under controlled storage it lasts for more than 2 months. The fruits ripens over a period of 6-7 weeks depending on environmental conditions hence can be left on the tree without rotting as the grower organizes for better market.

Challenges: Lack of adequate clean planting material is a serious challenge in production. Propagation is by use of cuttings or seeds from the locally planted trees. This may lead to disease transfer if cuttings or seed are obtained from unhealthy plants. Care should be taken while sourcing for planting material.

Note: Planting material should be obtained from registered tree nurseries.

Advice to potential growers

This enterprise is growing with high prospects due to increased demand for the fruits. Market supply is low hence the price of fruits is very high. Growers can organize for collective production within an area to ensure consistence supply and production for the targeted market. Value addition through juice making is an added advantage in marketing.  The relatively costs of orchard establishment is low, however it requires careful management to ensure high quality yields.