Spider plant (revised)

In East Africa, fresh leaves are used as ingredients in other mashed foods, and the dried leaves are ground and incorporated in weaning foods. Spider plant is believed to replenish blood and therefore referred to as a "traditional meat" by some Kenyan communities (Chweya and Mnzava, 1997; Savala et al, 2003). 

Related species

1. Cleome gynandra is likely to have originated in tropical Africa and Southeast Asia and is widely distributed in drier areas of the tropics and Subtropics. The vegetable is found mainly near human settlements in Africa. It occurs probably in all the countries of tropical Africa. 
2.  Cleome hirta occurs from Ethiopia and Somalis through Eastern and Central Africa to Southern Africa and has occasionally been introduced in Western tropical Africa and Madagascar. 
3. Cleome monophylla is widespread in tropical and subtropical Africa, including Madagascar and other Indian Ocean Islands, and is also found in India and Sri Lanka.
4.  Cleome rutidosperma is a pantropical weed of coastal regions and is widely distributed from Senegal to Angola, particularly in the coastal areas, but often extending deeply into the interior. Occasionally it has been found as a weed in East Africa (Uganda and Tanzania). In Nigeria, it occurs as a weed in rice fields. In West Africa, it is occasionally cultivated as a potherb.
5.    Cleome viscosa occurs in Northern Tropical Africa, from Cape Verde and Senegal to Egypt, Ethiopia, and Zanzibar; It is absent in Southern Africa but present in Madagascar and other Indian Ocean islands. Outside Africa, it is widespread in Peninsular Arabia, Tropical Africa, Australia, and tropical and subtropical America.
6. Cleome allamanii, locally called Mwangani muthithe (meaning small spiderplant) is found in East African coast.
7.  Cleome usambarica, occurs in Sudan, Ethiopia, Kenya, and Tanzania.(Grubben, G.J.H. & Denton, O.A, 2004, Chweya J.A. & Mnzava N.A, 1997, Nana, P. & Foyet, H.S, 2013)

Species accounts

Cleome gynandra is an erect herb to 1.3 m high (usually 0.5-1.0 m). Stems hairy, rather oily. Leaves: On long stalks, usually divided into 3, 5, and 7 leaflets, to 7 cm long. Flowers: White or pink borne on a long much-branched inflorescence. Fruit: A long-stalked capsule splitting to release small rough, greyish-black seeds. It is a fast-growing plant ready for harvest in as few as three weeks. The leaves are eaten as a cooked green vegetable, have a mildly bitter taste. (Maundu et al, 1999, Savala et al., 2003, Mnzava et al., 2004)

Cleome hirta is a bushy annual to short-lived perennial plant with an erect, much-branched stem growing up to 1.5 m. The stem is covered with glandular hairs, which can also be found in other parts of the plant, and is sticky to the touch.
The plant can be found in various habitats, such as deciduous woodland, dry savanna grassland, and sandy plains. As a weed, the plant can be found on the roadside, in disturbed soils, and in farmland. It is used as a vegetable in Tanzania, Uganda, DRC Congo, and Zimbabwe. The leaves are taken to reduce hypertension, and the boiled roots are used to cure measles in various parts of Africa. (Grubben, G.J.H. & Denton, O.A, 2004, Fern, 2021)

Cleome monophylla (spindle pod) is an annual herb that can grow up to 1 meter in height. It is found in various habitats, including savannah grasslands, deciduous woodlands, bushlands, lakeshores, disturbed land, and cultivated areas. The plant has simple leaves and a spindle pod that lacks robust branching, distinguishing it from C. gynandra and C. hirta. It is less bitter than C. gynandra, making it a preferred choice, and can be identified by its pink petals, slightly hairy oblong leaves, and stamens not much longer than the corolla. C. monophylla, despite its unpleasant odor, is a highly versatile plant that has found numerous uses in Africa. The pounded seeds of this plant are often used as a substitute for mustard, while the young leaves and shoots are employed as a flavorful addition to various dishes. Medicinally. In Nigeria, crushed leaves are used against headaches, and finely ground leaves are used to remove irritating particles from the eyes. In Tanzania, the dried ground leaves are used for sores, and the roots are chewed to treat cough. The entire plant is used externally to treat swelling. The essential oil extracted from C. monophylla has been found to repel the tick (Riphicephalus appendiculatus) and the maize weevil (Stophilus zeamais). (Ndungu et al., 1994, Grubben, G.J.H. & Denton, O.A, 2004, Schippers, R. R, 2000)
Cleome rutidosperma is an erect annual herb growing up to 0.5 m tall and branched from the base. The stem is green with a purplish tinge and is covered in fine hairs or glandular pubescence. It is adapted to thrive in humid and hot conditions, primarily in low attitudes. Typically, it is found in areas with an annual rainfall of 1700-3000 mm and can grow up to 400m Latitude. The leaves of this plant are collected from the wild and can be cooked as a vegetable or added to soup. The leaves have a bitter taste, similar to mustard, and in Uganda, butter is added to enhance the vegetable's flavor. In Ghana, Gabon, and DRC Congo, the leaf sap is used to cure earaches and deafness. In Ghana, the leaf extract treats skin irritation, while in Nigeria, it treats convulsions. In Malaysia, the plant is used to control insects, particularly by diverting diamondback moths' oviposition from cultivated plants. (Grubben, G.J.H. & Denton, O.A, 2004).

Cleome viscosa is an annual sticky herb growing up to 1 meter tall. The plant has a robust penetrating odor when bruised and is clothed with yellowish glandular hairs; the plant occurs in woodland and grassland and is a weed of fallow land fields, roadside, and wasteland, often occurring in sandy soils. It is found under seasonal dry and humid conditions, from sea level up to 1000 m altitude. In tropical Africa, C. viscosa is occasionally used as a leafy vegetable. The bitter leaves are locally popular and eaten fresh, dried, or cooked. The picked young fruits are also eaten. The plant is used as an essential covers crop and green manure in areas where it occurs in abundance. The whole herb is rubbed on the body against rheumatism. The seeds and their oil have anthelminthic properties but are ineffective in treating roundworm infections. The roots remedy scurvy and rheumatism (Grubben, G.J.H. & Denton, O.A, 2004, Ravindra G. Mali., 2010).

Cleome usambarica occurs in Sudan, Ethiopia, Kenya, and Tanzania. A cold water infusion of the roots, together with the roots of Macaranga capensis is taken in Kenya before a meal twice a day as an aphrodisiac. (Nana, P. & Foyet, H.S., 2013). Young leaves of spiderplants are widely used as spinach in Africa. These leaves can be dried and stored for later use, usually as a relish eaten with maize meal. This food is rich in magnesium and iron, as well as nicotinic acid.
(EcoPort (http://www.ecoport.org): Roger P. Ellis)

Variation in spiderplant 
Spiderplant exhibits immense variation, especially in East Africa. Various morphological characteristics such as leaflets and the pod shape, stem and petal color, the texture of the pods, and stem and leaf hairiness display significant variation.
Although the spiderplant species is found throughout Africa and Asia, little is known about its genetic diversity. Recent studies conducted in Kenya and Zimbabwe have identified variations in physical characteristics among different plant populations, including differences in plant type, stem, petiole pigmentation, petiole length, plant height, number, size, and shape of leaflets, as well as stem and leaf pubescence. Other variations include differences in day-to-flowering, stem diameter, branching habit, number of primary branches, leaf color, days to seedling emergence and vigor, flowering tendency, fruit position, fruit length, disease susceptibility, and plant lodging. 
The extent to which environmental factors, such as soil fertility and climatic conditions, contribute to these variations requires further investigation. Germplasm collections are maintained in various African countries, including Botswana, Kenya, Namibia, Tanzania, Zambia, and Zimbabwe.
(Mnzava, N.A. & Chigumira Ngwerume, F., 2004; Chweya J.A. & Mnzava N.A, 1997; Schippers, R. R, 2000).

Ecological information

Climatic conditions, soil and water management

Spider plant is commonly found throughout East and Southern Africa during the rainy season. (AVRDC). In Kenya, it grows from sea level to 2400 metres (Savala et al, 2013). The crop grows well during the warm season under irrigation. Spider plant is sensitive to cold and does not grow well when temperatures drop below 15 °C. It thrives on sandy loam soils but does not perform well on wet, marshy and heavy clay soils. It requires exposure to sunlight and does not do well in the shade. Although the plants are able to tolerate short-term drought, periods of drought will hasten development of flowers and lower the yields (AVRDC).

Seeds should be sown at the onset of rainfall. This ensures availability of adequate soil moisture throughout the growth period. When rainfall is inadequate, frequent watering is necessary during the vegetative growth period (Chweya and Mnzava,1997; Savala et al, 2003).  

Agronomic aspects

Propagation and planting

Propagation is done by seed.

Seeds are sown directly in a well prepared seedbed. Transplanting has proved unsuccessful. (EcoPort) Seeds can be extracted when the pods are fully ripe (yellow or black), but before they open naturally. Seeds should be kept in a dry, closed container for at least three months to reduce dormancy (AVRDC). It requires a well-prepared seedbed without weeds and dug to a depth of about 15 cm followed by a light harrowing. It may be planted on traditional raised or flat beds. After digging, the soil is harrowed to a fine tilth. Organic manure is applied and worked into the soil. The seedbed is then levelled before planting. Plants can be grown on flat beds or on traditional raised beds, which are normally one m wide. The appropriate bed length depends on the amount of the crop to be grown, but may not exceed three metres. There are usually narrow pathways between the beds to facilitate weeding and harvesting. These pathways also act as drainage channels during the very wet season, as plants do not withstand waterlogging. When raised beds are used, application of organic manure is delayed until the beds have been dug (Chweya and Mnzava,1997). Shallow planting at one cm depth and with 30 cm between rows or broadcasting followed by raking on prepared seedbeds is recommended. Some farmers mix the seeds with sand when broadcasting them. About four g of seed per m² or 40 kg per ha are required. Emergence is normally from 6 to 8 days after sowing. Thinning is done three weeks after emergence to leave 10 to 15 cm between plants (EcoPort).  

Planting
To prepare a suitable seedbed for planting, start by digging to a depth of 15cm and remove weeds. After digging, the soil should be harrowed to a fine tilth. Raised beds are preferable in wet, humid areas, while sunken beds are recommended in dry regions. Mix farmyard manure or compost thoroughly into the soil, and level the seedbed before planting. Divide the prepared land into beds not wider than one meter, with pathways between them to facilitate weeding and harvesting. These pathways also act as drainage channels during the wet season, as plants do not withstand waterlogging. The appropriate bed length depends on the amount of the crop to be grown but may not exceed three metres. When raised beds are used, the application of organic manure is delayed until the beds have been dug. Shallow planting at a depth of 1 cm and a spacing of 30 cm between rows or broadcasting followed by raking on prepared seedbeds is recommended. Some farmers mix the seeds with sand when broadcasting them. About 4 g of seed per m2 or 40 kg per ha are required. After sowing, the bed should be covered with a thin layer of soil to prevent ants from carrying the seeds away or birds from picking them. Emergence typically occurs 6 to 8 days after sowing. Thinning should be done 3 weeks after emergence to leave 10 to 15 cm between plants.
(Schippers, R. R, 2000; Chweya J.A. & Mnzava N.A., 1997, EcoPort)
 

Plants do not have dense foliage, and as such are unable to compete with weeds. It is therefore essential that seedbeds are kept weed-free at all times, but especially during the first six weeks. Shallow cultivation or hand-pulling of weeds should be practised (Chweya and Mnzava, 1997) Spider plant responds well to well-decomposed manure. Flowering is delayed when adequate manure is available, allowing more, larger leaves to be harvested.

Optimum yields could be obtained with an application of 20 to 30 tons of manure per hectare. Topping and removing inflorescences as soon as they appear are other practices that increase leaf production for harvesting. This crop grows rapidly and requires weeding only in the open space between the rows. Plants require water two or three times a week. Periods of drought will hasten development of flowers and lower the yields. Pests and diseases are not usually serious and spraying with insecticides is not recommended even when aphids appear to become problematic. (AVRDC; Chweya and Mnzava, 1997).

Harvest, post-harvest practices and markets

Harvesting
The seedlings are thinned when the plants reach a height of 15 cm, which constitutes the first harvest. When adequate space has been created, the top shoot from the remaining plants will be picked, allowing new side shoots to develop. Some farmers pick the tender leaves and young shoots while others wait for the shoots to grow and harvest them when they are about 25 cm long 
Plants are brought to the market with their roots attached; roots are removed just before selling to maintain freshness. Where possible, roots should be placed in water overnight to absorb moisture. In the case of mixed cultivation with amaranths or nightshades, spiderplant are uprooted to make more space for the companion crop. In the case of monocropping, which is more common, the tops are removed 10 cm from the ground. This encourages the development of side shoots. Harvesting is repeated several times, depending on the soil fertility and moisture conditions. After several successive leaf harvestings, the plants are left to flower and produce seeds. Growers harvest the ripe capsules at the end of the rainy season to save seeds for the next crop (AVRDC &IPGRI, 2006, Chweya J.A. & Mnzava N.A., 1997).

Post-harvest practices 
Spiderplant is a delicate plant that tends to wilt readily when exposed to the sun. Once harvested the leaves should be stored in a very airy environment; otherwise, it will begin to 'cook,' yellow, and produce a foul smell. It has a very short shelf life, and thus, care should be taken right from the harvesting time. Harvesting should be in the evening if the plants are being marketed the following day or early in the morning if sold on the same day.
Thinned plants that are uprooted and whole have their roots chopped off, and the stems are then washed to clean off the remaining soil. Plants are then tied up into bunches and placed on a wire mesh; care is taken not to stack the plants. Sun drying of leaves provides an additional marketing opportunity for use during the dry season. For the sun drying, the leaves are allowed to wilt a bit before being blanched and spread to dry in the sun. In Botswana and Namibia, the fresh leaves are cooked for 2 hours with salt added to remove the bitter flavor. The boiled leaves are kneaded into small balls, which are then sun-dried. These balls can be stored until the next rainy season; soaking them in water reconstitutes the leaves, after which they can be prepared for a meal in the same way as the fresh produce. In Namibia, the processed leaves are marketed as "Omuvanda cakes" (Grubben, G.J.H. & Denton, O.A, 2004, AVRDC & IPGRI, 2006, Mnzava, N.A. & Chigumira Ngwerume, F., 2004)

Markets
Spiderplant is now a common vegetable in markets in countries where it is grown. In Southern African countries, the dried form is common in local open-air markets. In Kenya, the vegetable is now dried, packaged and exported for the diaspora market.