Geographical Distribution of Moringa in Africa
General Information and Agronomic Aspects
Moringa is a slender, fast growing, deciduous shrub or small tree reaching 9 to 15 m in height, with an umbrella shaped, open crown. It is an exceptionally nutritious tree with a variety of potential uses.
Almost every part of plant is of value for food. Seed is said to be eaten like a peanut in Malaysia. The thickened root is used as a substitute for horseradish. Foliage is eaten as greens, in salads, in vegetable curries, as pickles and for seasoning. Seeds yield 38 to 40% of a non-drying oil, known as "ben oil", used in arts and for lubricating watches and other delicate machinery. Ben oil is clear and odourless, has an unusually long shelf life, never becoming rancid. It is edible (with a sweet, mild pleasant taste) and useful in the manufacture of perfumes and hairdressings.
Climatic conditions, soil and water management
It grows best in direct sunlight below 500 metres altitude, but it can grow in altitudes up to 1200 m in the tropics. It grows best between 25 to 35degC, but will tolerate up to 48degC in the shade and can survive a light frost. It tolerates a wide range of soil conditions, but prefers a neutral to slightly acidic (pH. 6.3 to 7.0), well-drained sandy or loamy soil. Minimum annual rainfall requirements are estimated at 250 mm with maximum at over 3,000 mm, but in waterlogged soil the roots have a tendency to rot. (In areas with heavy rainfall, trees can be planted on small hills to encourage water run-off). Presence of a long taproot makes it resistant to periods of drought. It readily colonises stream banks and savannah areas where the soils are well drained and the water table remains fairly high all the year round (EcoPort; AVRDC; Fuglie; Moringa Farms)
Propagation and planting
- Moringa trees grow easily from seeds or hard-stem cuttings. When using seeds they can be directly sown in the field or used for raising seedlings in nursery beds and transplanted. Direct seeding is preferred when plenty of seed is available and labour is limited, and when enough water is available. Thus, direct seeding can be done in the backyard garden, when there is enough water available for irrigation. In a large field, trees can be seeded directly at the beginning of the wet season. Transplanting allows flexibility in field planting but requires extra labour and cost in raising seedlings. Stem cuttings are used when the availability of seed is limited but labour is plentiful.
Moringa seeds have wings and are about the size of a large pea. Seeds do not need sunlight in order to germinate. Moringa seeds have no dormancy period, so they can be planted as soon as they are mature and they will retain the ability to germinate for up to one year (Fuglie, Trees for Life, AVRDC). To encourage rapid germination, one of three pre-seeding treatments can be employed:
- Soak the seeds in water overnight before planting.
- Crack the shells before planting.
- Remove shells and plant kernels only.
- Choose an area with light and sandy soil, not heavy with clay or water-logged.
- If planting a large plot it is recommended to first plough the land.
- Prior to planting a seed or seedling, prepare a planting pit by digging holes 30 to 50 cm wide and deep, water, and then fill in the pit with topsoil mixed with compost or manure (at the rate of 5 kg per pit ) before planting seeds. This planting hole serves to loosen the soil and helps retain moisture in the root zone. This will enable the roots of the seedlings to develop rapidly. Compost or manure will help the tree grow better, even though Moringa trees can grow in poor soils. Avoid using the soil taken out of the pit for this purpose: fresh topsoil contains beneficial microbes that can promote more effective root growth.
- Moringa can also be planted on 30-cm-high raised beds to facilitate drainage (AVRDC).
To plant seeds directly in the ground:
- Plant 2 or 3 seeds in each hole, 5 cm apart. Plant the seeds at a depth of 2 cm (approximately the size of one's thumbnail).
- Do not water heavily for the first few days. Keep the soil moist enough so that the top soil will not dry and choke the emerging saplings, but not too wet or else the seeds can drown and rot.
- Two weeks after germination, or when the seedlings are 10 to 15 cm tall, keep the healthiest seedling in the ground and remove the rest.
(Fuglie, Trees for Life, AVRDC)
In the nursery:
Seedlings for transplanting can be grown in divided trays, individual pots, plastic bags, or seedbeds. Use of divided trays and individual containers such as poly bags is recommended because there is less damage to seedlings when they are transplanted. Grow seedlings under shade or in a screenhouse.
Use poly-bags with dimensions of about 18 cm in height and 12 cm in diameter. The soil mixture for the bags should be light, i.e. 3 parts soil to 1 part sand. Plant 2 or 3 seeds in each bag, 1 to 2 centimetres deep. Keep moist but not too wet. Germination will occur within 5 to 12 days, depending on the age of the seed and pre-treatment method used. Remove extra seedlings, leaving the strongest seedling in each bag. Seedlings can be transplanted in the field when they are 60 to 90 cm high. When transplanting, cut a hole in the bottom of the bag big enough to allow the roots to emerge. Be sure to retain the soil around the roots of the seedling (AVRDC).
Transplanting to the field
- The day before transplanting, water the filled pits (see land preparation) or wait until a good rain before out-planting seedlings. Fill in the hole before transplanting the seedling. In areas of heavy rainfall, the soil can be shaped in the form of a mound to encourage drainage
- Do not water heavily for the first few days. Keep the soil moist enough so that the topsoil will not dry and choke the emerging saplings, but not too wet or else the seeds can drown and rot.
- If the seedlings fall over, tie them to stick 40 cm high for support.
Growing from cuttings
To grow trees from cuttings use hard wood, avoid using young green stem tissue. Cut off the branches after the trees have stopped producing fruits. This will promote fresh growth and the cut branches provide excellent cuttings for growing new trees. Compared to trees planted from seed, trees from stem cuttings grow faster but develop a shallow root system that makes them more susceptible to moisture stress and wind damage.
Cuttings can be planted directly or planted in sacks in the nursery. When the cuttings are planted in the nursery, the root system is slow to develop. Cuttings planted in a nursery can be transplanted after 2 or 3 months. Cuttings can be 45 to 180 cm long with diameters of 4 to 16 cm. Cuttings can be dried in the shade for 3 days before planting in the nursery or in the field.
When planting direct in the field:
- Dig a hole 1m x 1m wide and 1 m deep
- Place cutting in this hole and fill with a mixture of soil, sand and composted manure. Pack firmly around base of the cutting. This will facilitate drainage. It is not desirable that water touches the stem of the new tree
- Water generously, but do not drown the cutting in water. If the soil is too heavy or wet, the roots may rot.
In India, some cow dung is put on top of the open end of the cutting to protect the cutting from pests (Trees for Life)
For intensive moringa production, plant the tree every 3 metres in rows 3 metres apart. When the trees are part of an alley-cropping system, there should be 10 metres between the rows. The area between trees should be kept free of weeds (Fuglie and Sreeja).
The Asian Vegetable Research and Development Center (AVRDC) recommends, if using raised beds, to form beds with 2-m-wide tops, and space plants 3 to 5 metres apart in a single row. For production of leaves only, space plants 50 cm within rows 1 metre apart. For intensive production of leaves, space plants 10 to 20 cm within rows 30 to 50 cm apart. Closer spacing allows harvest of young edible shoots every 2 to 3 weeks.
Trees are often spaced in a line 1 metre apart or closer to establish living fence posts.
Moringa trees are planted in gardens to provide support for climbing crops such as pole beans, although only mature trees should be used for this purpose since the vine growth can choke off the young tree. Moringa trees can be planted in gardens to provide shade to vegetables less tolerant to direct sunlight. Trees are planted in hedgerows forming wide alleys where vegetables are planted within. Choose vegetables that are adapted to alley cropping, such as shade-tolerant leafy vegetables and herbs, since moringa hedgerows are highly competitive and can reduce yields of companion plants significantly. From the second year onwards, moringa can be intercropped with maize, sunflower and other field crops. Sunflower is particularly recommended for helping to control weed growth. However, moringa trees are reported to be highly competitive with eggplant and sweet maize and can reduce their yields by up to 50% (Fuglie and Sreeja; AVRDC).
Moringa trees do not need much watering. In very dry conditions, water regularly for the first two months and afterwards only when the tree is obviously suffering. moringa trees will flower and produce pods whenever there is sufficient water available. If rainfall is continuous throughout the year, moringa trees will have a nearly continuous yield. In arid conditions, flowering can be induced through irrigation.
Pinching the terminal tips: When the seedlings reach a height of 60 cm in the main field, pinch (trim) the terminal growing tip 10 cm from the top. This can be done using fingers since the terminal growth is tender, devoid of bark fibre and brittle, and therefore breaks easily. A knife blade can also be used. Secondary branches will begin appearing on the main stem below the cut about a week later. When they reach a length of 20 cm, cut these back to 10 cm. Use a sharp blade and make a slanting cut. Tertiary branches will appear, and these are also to be pinched in the same manner. This pinching, done four times before the flowers appear (when the tree is about three months old), will encourage the tree to become bushy and produce many pods within easy reach. Pinching helps the tree develop a strong production frame for maximising the yield. If the pinching is not done, the tree has a tendency to shoot up vertically and grow tall, like a mast, with sparse flowers and few fruits found only at the very top. During its first year, a moringa tree will grow up to five meters in height and produce flowers and fruit. Left alone, the tree can eventually reach 12 meters in height with a trunk 30 cm wide; however, the tree can be annually cut back to 1 metre from the ground. The tree will quickly recover and produce leaves and pods within easy reach (Fuglie).
When harvesting pods for human consumption, harvest when the pods are still young (about 1 cm in diameter) and snap easily. Older pods develop a tough exterior, but the white seeds and flesh remain edible until the ripening process begins.
When producing seed for planting or for oil extraction, allow the pods to dry and turn brown on the tree. In some cases, it may be necessary to prop up a branch that holds many pods to prevent it breaking off. Harvest the pods before they split open and seeds fall to the ground. Seeds can be stored in well-ventilated sacks in dry, shady places.
For making leaf sauces, harvest seedlings, growing tips or young leaves. Older leaves must be stripped from the tough and wiry stems. Older leaves are more suited for making dried leaf powder since the stems are removed in the pounding and sifting process (Fuglie).