Okra (Revised)

Introduction

Okra (Abelmoschus esculentus) also known as lady's finger, is a herbaceous flowering plant that belongs to the Malvaceae (Mallow family) and the genus Abelmoschus. The mallow family also includes other economically important plants such as cotton and cocoa. The genus Abelmoschus originated in south east Asia and comprises about 15 species. There are two important species in the genus Abelmoschus in Africa. Abelmoschus esculentus, commonly known as okra can be found in tropical, subtropical, and warm temperate regions worldwide. A. caillei, known as West African okra, is primarily found in West and Central Africa, with reported sightings from Guinea to Nigeria in West Africa, and in Cameroon, Gabon, DR Congo in Central Africa, and Uganda in East Africa. 

The most common and widely known use of okra is as a culinary vegetable. Its young, tender fruits are consumed cooked or fried, often added to stews, soups, curries, or simply sautéed or fried. Okra's mucilaginous nature adds a unique texture to dishes. It is a common ingredient of soups and sauces. The pods can be conserved by drying or pickling. The leaves are sometimes used as spinach or cattle feed, the fibres from the stem for cord, the plant mucilage (thick gluey substance) for medical and industrial purposes, and the seeds as a substitute for coffee.
Okra leaves have a range of uses, such as making poultices, soothing the skin, inducing perspiration, and addressing dysuria. The mucilage from okra is employed in paper glazing and confectionery. Bark fibers are locally utilized for crafting fishing lines, game traps, ropes, paper, and cardboard. In certain areas, roasted okra seeds serve as a coffee alternative.
Additionally, okra is a nutritious vegetable with low calorie and fat content but abundant in essential nutrients. It's a valuable source of dietary fiber, which aids digestion and supports gut health. The vegetable also contains vital vitamins such as A, C, K, B6, and folate, along with minerals like calcium, magnesium, potassium, and iron.
Besides its fresh consumption, okra can undergo preservation techniques like freezing and canning. It is a global commodity traded in fresh and processed forms, with major producers including India, Nigeria, Pakistan, and Egypt.
In Africa, countries such as Nigeria, Ghana, and Burkina Faso are significant producers and consumers of okra. The vegetable carries cultural importance in African cuisine and plays a vital role in traditional dishes. (Orwa C et al.,2009, Siemonsma, J.S. & Hamon, S., 2004) .

Species accounts

Okra (Abelmoschus esculentus) is an annual, herbaceous plant that grows upright, reaching heights of 4 to 6 feet (1.2 to 1.8 meters). Stems: sturdy and covered with fine hairs, while the leaves are broad, palmate, and lobed, giving them an attractive and distinctive appearance. Flowers: large, hibiscus-like flowers that can be either white or yellow in color, with a deep red or purple center. These eye-catching flowers are about 2 to 3 inches (5 to 7.5 centimeters) in diameter and have five petals. Fruit: elongated, green, typically 4 to 8 inches (10 to 20 centimeters) long and have a ridged, tapered shape, resembling a slender finger, which is how it gets its name "Lady's Finger." The pods are edible and harvested for culinary purposes. Seeds: numerous small, round, and flat seeds within the pods. These seeds are the reproductive structures of the plant and can be saved for replanting or used for oil extraction.

Abelmoschus caillei commonly known as the West African okra is an annual or biennial herbaceous plant that can grows to a height of 1 to 3 meters. It has a bushy and upright growth habit. Stem: typically, solid, sometimes hollow, green and may have some fine hairs.
Leaves: palmately lobed and palmately veined, usually dark green and can be quite large, measuring up to 20 cm in length. Flowers: large, showy flowers that are typically yellow with a dark purple or maroon center, about 5-8 cm (2-3 inches) in diameter and have five petals. They are borne singly on axillary peduncles. Fruit: a capsule similar in appearance to the okra (Abelmoschus esculentus) but is typically smaller and has a more elongated shape. The capsules are often covered in fine hairs and contain numerous seeds. These capsules are edible, and the seeds are used for propagation.
A. caillei is a tropical plant that thrives in warm and humid climates. It is a cultivated species primarily found in West and Central Africa, with documented occurrences from Guinea to Nigeria in West Africa, Cameroon, Gabon, and the DRC in Central Africa, and Uganda in East Africa. The young unripe okra fruits are a valuable vegetable often cooked or fried. In west Africa, they are commonly boiled for slimy soups and sauces. The fruits can also be dried, either whole or sliced, and then ground into powder before sale. Occasionally the leaves are consumed as a spinach substitute. (Siemonsma & Hamon, 2004, Rojas‐Sandoval, 2022). 

Related species/ common name

1.    Abelmoschus caillei (A. Chev) Stevels- West African okra, West African okro (English), Gombo oust-africain, Gumbo oust-africain (French)

Varieties available in Kenya:
•    "Pusa sawani" High yielding variety tolerant to vein mosaic. It grows 2 to 2,5 m tall, has long pods. (18 to 20 cm), dark green, smooth and has 5 ridges. Mainly for export.
•    "Clemson spineless" 1.2 to 1.5 m tall. Pods are about 15 cm long, green and moderately ridged.
•    "Green Emerald2 This variety is about 1.5 m tall. Pods are 18 to 20 cm long slightly ridged (rounded) and green.
•    "White velvet" A medium tall variety of 1.5 to 1.8 m high. Pods are 15 to 18 cm long, slender, tapered, smooth and creamy white.
•    "Dwarf Green Long Pod" It grows up to 0.9 m high. It has several side branches. The pods are angular and green and about 18 to 20 cm long.

 
Ecological conditions

Okra is grown at elevations ranging from sea level to 1600 m. The optimum temperatures for growth and production of high quality pods range between 24 and 30degC. The crop is sensitive to frost and temperatures below 12degC. 
Okra will grow on a wide range of soils, but it prefers soils high in organic matter. When grown in sandy soils, it must be frequently fertilized, as soluble nutrients readily leach from the root zone. Its optimum range of soil pH is between 5.8 and 6.5. A soil test will indicate if lime is required to adjust the pH and the amount to apply. If lime is recommended, dolomite should be used, applied 3 to 4 months before the crop is seeded. Okra is sensitive to salinity. Okra can grow in a wide range of rainfall regimes, but needs 400 mm of water for the growing period of about 3 months.

Agronomic aspects

Land preparation 
Thorough soil preparation 2 to 3 months before planting is recommended to allow crop residues and organic matter in the soil to decompose before okra is planted. Early land preparation also permits seeds to germinate and allows early cultivation to destroy young weeds before planting. 
 
Planting 
Okra plants may be established by direct seeding in the field, by growing seedlings in nursery seedbeds or by raising seedlings in plastic trays. To facilitate speedy germination, okra seed should be soaked in water overnight before planting. In Kenya, okra is sown directly in the field. About 8 to 10 kg of seed is required per hectare. Planting depth is about 1.5 cm.
Spacing varies: 45 x 45 cm, 50 x 30 cm or 60 x 15 cm between the rows and within the rows, respectively. In some parts of Kenya, okra is planted 2 x 2 m in flood irrigation basins. The main export season in Kenya is October to May; hence planting should start from July so as to target this export season. However, with irrigation okra can be grown all year round for the local and off-season export markets. 
 

Fertilization
 It is recommended that soil be analysed before okra planting to determine fertility treatment needed. Without a soil test, the general recommendation in Kenya (issued by Horticultural Crops Development Authority) for conventional production (non-organic production) is as follows: well-composted manure should be applied at planting at the rate of 15 to 20 t/ha (17 to 20 gm/plant). It should be mixed thoroughly with the soil in the planting hole.

Sources of plant nutrients 
In organic management we have to rely on the natural sources of plant nutrients such as compost, manure teas, plant teas such as tithonia for foliar feed. Well-composted manure should be applied at planting at the rate of 15 to 20 t/ha (17 to 20 gm/plant). Additional compost or manure is needed during the vegetation period. Manure and plant teas can be fed to the plants via a drip irrigation system to avoid excessive labor. However, on acid soils agricultural lime is recommended and allowed. Also Mijingu (rock phosphate) is recommended on soils low in phosphorous (almost all soils in Kenya).
 
Irrigation
 Okra is a heavily foliaged crop, so its water requirements are high. According to the Kenya Ministry of Agriculture okra needs 400 mm of water during the growing season of three months. A general guideline for semi-arid areas, where okra is mostly grown in Kenya, is to provide about 35 mm of water per week (this equals 35 litres of water per square metre). Critical times for irrigating okra are at emergence and from flowering to pod production. Saline or chlorinated water should not be used for irrigation. 
 
Rotation
Okra should be rotated with baby corn, maize, peas, onions, potatoes, fodder grass or small grains. Being in the same family as cotton - with which it shares the same complex of pests and diseases - okra should not be grown before or after cotton. 
 
Weed control 
Okra is harvested over a long period and weed control is important throughout the cropping season. Smallholder growers in Kenya control weeds by hand hoeing.

Harvest, post-harvest practices and markets 

Harvest
Okra is ready for harvesting about 50-60 days after planting. Pods are harvested when still tender and on attaining length of 7 to 15 cm, depending on variety and market requirements. Overripe okra tends to be tough and less palatable. The crop will bear pods for several months under ideal conditions, especially when mature pods are picked regularly. Regular picking every 1 to 2 days is essential to ensure pods are within the size prescribed by the market. Okra should not be harvested when it is raining or excessively wet. Excess moisture can induce mould development on the pods and the cut petioles. Okra pods decay quickly; therefore, they should be harvested within a day to marketing. 
Harvesting is done by hand. The pods can be snapped off or cut off, leaving a small stalk not longer than one cm. The pods must be handled carefully otherwise they may be bruised and may discolor. It is best to pick pods into a waist bag to reduce skin damage and to avoid excessive bending of the pods. Wearing rubber gloves when harvesting and handling pods is recommended. This will protect the skin from irritating sap produced by okra plant.

Post-harvest practices.
During the cleaning process, it's common practice to eliminate leaves, stem fragments, and any other debris from Okra pods. It's advisable not to rinse Okra since doing so can raise the chances of post-harvest spoilage. The initial grading of freshly harvested okra should take place right in the field during the harvesting process. In this step, any pods that are unmarketable or damaged should be separated from the ones suitable for sale by field workers. Additionally, any pods that are excessively large or partially spoiled should be promptly removed from the plants and graded in the field. Despite this initial sorting during harvest, the okra pods brought in from the field usually exhibit a wide range of sizes, shapes, and colors. To meet the buyer's expectations, it's essential to ensure a consistent and uniform appearance.
Subsequently, at the packing house, the okra pods are typically graded based on their size, shape, overall appearance, and the presence of surface defects. The okra pods that are intended for the market must meet specific criteria: they should be fresh, tender, not significantly misshapen, and free from any signs of decay or damage.
Okra should be packaged in well-ventilated containers or perforated plastic bags to allow for proper air circulation. Avoid over-packing to prevent bruising and damage.
Okra is sensitive to temperature and humidity. The pods can be preserved for a long time at temperatures ranging from 15 to 280 degrees Celsius and 85 to 95 percent relative humidity 

Markets

The global okra production is estimated to be around 9.96 million tons, India leading with 6.18 million tons followed by Nigeria with 1.82 million tons (FAOSTAT, 2020)

Nutritional value and recipes

Okra, also known as lady's finger or gumbo, is a nutritional powerhouse with a wide array of health benefits. Okra particularly rich in vitamin C, which strengthens the immune system and nurtures healthy, radiant skin. Additionally, vitamin K found in okra supports blood clotting, ensuring proper wound healing, and aids in maintaining strong bones. Another crucial vitamin found in okra is folate, which plays a pivotal role in cell division and is especially important during pregnancy for the healthy development of the baby.
The mineral content of okra is equally noteworthy. It offers a generous supply of essential minerals such as magnesium, calcium, and potassium. These minerals are instrumental in maintaining bone health, supporting proper nerve function, and promoting a healthy heart.
With its high dietary fiber content, okra is an ally for digestive health. Fiber aids in digestion, preventing uncomfortable constipation, and helps maintain a healthy gut environment.
Okra also provides a good dose of antioxidants, including flavonoids and polyphenols. These powerful compounds are valuable in neutralizing harmful free radicals that can damage cells and tissues, thus reducing oxidative stress and contributing to overall health. 
(WebMD, 2020, Healthline, 2023)
 
Table 1: Proximate nutritional value of 100g of Okra.

Source (Nutrient data): FAO/Government of Kenya. 2018. Kenya Food Composition Tables. Nairobi, 254 pp. http://www.fao.org/3/I9120EN/i9120en.pdf

RE=retinol equivalents.

RAE =Retinol activity equivalents. A RAE is defined as 1μg all-trans-retinol, 12μg beta-carotene, or 24μg α-carotene or β-cryptoxanthin.

^$ Draining the water several times leaches away water soluble nutrients significantly.

^a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO

^b NHS (refers to saturated fat)

^c https://www.hsph.harvard.edu/nutritionsource/water/

^d British Heart Foundation

^e FDA

^f NIH

^g Mayo Clinic

Nutritive Value per 100 g of edible Portion

*Percent Daily Values (DV) are based on a 2000 calorie diet. Your daily values may be higher or lower, depending on your calorie needs

Recipes

1. Mlenda wa majani ya maboga na bamia
(Luguru, Morogoro, Tanzania)

Ingredients 
Pumpkin leaves
Okra 
Nyanya chungu (Eggplant, Solanum aethiopicum)
Salt 
Water 

Procedure 

1. Cut up pumpkin leaves
2. Cut up okra
3. Cut up nyanya chungu
4. Add salt
5. Boil with half water of the vegetable for 15 minutes

Served with Ugali 
(not ubwabwa – rice gruel)

Alternative cooking:
If you want you can add groundnut then let boil for one minute
Note: Pumpkin alone, without bamia can be eaten with ubwabwa
 
2. Dongodongo (Gombo in French
(Lingala, DRC)

Ingredients
2 tablespoonfuls sunflower or cooking oil
120 g tomatoes 
10 g green pepper 
60 g onions 
1 cup water
500 g okra fruits
200 g smoked fish pieces
Salt to taste

Preparation 
Pick the youngest fruits of okra and clean them
Cut them into small pieces
Heat the oil, add the chopped onions and fry them till they begin to turn golden brown
Add the chopped tomatoes, simmer and cook for 3 minutes
Add the chopped okra, mix and let cook for about 5 minutes till the green fruits turn grey-black
Add the smoked fish and salt to taste
Add water and let cook for about 20 minutes
Serve with ugali or rice
Yields 6 servings

Remarks
Although this plant is widespread in DRC, it is commonly grown in the lower part of the county (Bas-Congo). It is a favorite food of the Bakongo people. In the central part of the country, the Baluba of Kasai region serve it with fufu.
Source: Cyrille Okulungu, DRC.

3. Delele yo Vundula 
(Zambia)
Ingredients
150 g (1 cup) dried okra
2.2 liters (5 cups) water
2 ¼ teaspoonfuls bicarbonate of soda    
225 g (1 cup) raw pounded groundnuts
Salt to taste
200 g (2 medium) tomatoes

Preparation
Pound the okra and the groundnuts together then sieve
Put the water into a saucepan, add the soda and boil
Add the resultant powdered meal a little at a time to the boiling ‘soda water’
Mix and boil for 5 minutes making sure that the ‘boil’ does not overflow
Add the finely chopped tomatoes, simmer, and let it cook till the groundnut oil begins to collect at the top
Serve with Nshima, or preferred starch
(Source: Maundu et al. 2006)