Pumpkin (Revised)

Introduction

Pumpkin refers to certain varieties of Cucurbita moschata, C. maxima, and C. argyrosperma. The native range of these species are: C. moschata – Mexico south to Guatemala (middle Central America); Cucurbita maxima: North Argentina, Peru and Bolivia; C. argyrosperma: Mexico to Nicaragua. These and other related cucurbits provide pumpkins and butternuts (Cucurbita moschata), squashes (C. maxima), gourds (C. argyrosperma), and zucchini or courgettes and ornamental gourds (C. pepo). Distinguishing them is often difficult. Pumpkins have long-running, bristled stems, large deeply-lobed leaves often containing white blotches and yellow or orange flowers separated into male and female types on the same plant. The fruit is variable in shape and colour but is often white, cream or green, containing about 70% flesh and several large white seeds.
Fruits, leaves and flowers of these cucurbits are used as vegetables, and their seeds are consumed roasted as a snack food. Pumpkin fruit contains 1% protein and 8% carbohydrates, and the dried seeds contain 23% protein, 21% carbohydrates and up to 50% oil, but little information is available about the nutritional characteristics of cooked leaves.

There are numerous types and cultivars, which differ greatly in composition and therefore in their suitability for certain culinary uses. The younger leaves are collected and the outer tough skin of petioles (stalk of leaf) removed (together with the large leaf veins) then washed, chopped and boiled. 
Immature and mature fruits of C. moschata are used as a blanched, steamed or fried vegetable and as an ingredient of soups. Various desserts are made from the fruits: steamed flesh with grated coconut and sugar, crisps made from steamed mashed flesh mixed with cassava flour, pumpkin custard, pumpkin pudding, pumpkin in coconut milk and sweet pumpkin paste. Ornamental gourds are cultivars of C. pepo with small, bitter and inedible fruits in many shapes, sizes and colors. The potential of the seeds as a source of vegetable fat and protein has not been fully exploited. Fresh seeds have been reported to be used as a vermifuge, and seed decoctions as diuretic and to reduce fevers.
The pumpkin has been much used as a medicine in Central and North America. It is a gentle and safe remedy for a number of complaints. The seeds are widely used as an anthelmintic. The complete seed, together with the husk, is used to remove tapeworms. They are especially useful effective as tapeworm treatment for children and pregnant women for whom stronger and toxic remedies are unsuitable. The seeds are ground into fine flour, then made into an emulsion with water and eaten. It is then necessary to take a purgative afterwards in order to expel the tapeworms or other parasites from the body. The fruit and seed decoctions have been reported to be used as diuretic and to reduce fevers, and are used for curing indigestion. The pulp is applied to burns and scalds, inflammation, abscesses and boils. It is also used in the treatment of migraine and neuralgia.
(Plants for a Future 2003; CAB 2006, Woomer and Imbumi, 2005).

Species accounts

Cucurbita moschata is an annual climbing plant with stems growing to a length of up to 5 metres. These stems tend to sprawl over the ground, though they also climb into the surrounding vegetation where they support themselves by means of tendrils. Leaves: large, lobed, and covered with soft hairs, sometimes with white markings often disappearing as the leaves age. Flowers: solitary, unisexual, lemon yellow to deep orange; sepals free. Fruits: may be of varying shapes and colour - globose to ovoid to cylindrical and may weigh up to 10 kg. It may be green to dark green often covered with grey-white stripes, changing to light green or cream with age. Flesh: yellow to orange, many-seeded; fruit stalk enlarged at apex. Seed: flattened, usually white. The fruit is ideal for roasting and in soups.

Cucurbita moschata is the most heat tolerant Cucurbita species and the most widely cultivated in tropical Africa. It is most probably cultivated in all countries of tropical Africa.
Cucurbita moschata includes important cultivars like pumpkins and butternut squash. C. moschata is commonly used as a leafy vegetable, where the young leaves and shoots are cooked and eaten as a green vegetable. Its fruit can be cooked in a variety of ways, including baking, roasting, and steaming. Its flesh can be used in soups, stews, casseroles and in pies and desserts.
(Grubben & Ngwerume, 2004, Tropical Plants Database (n.d), missouribotanicalgarden.org).

C. moschata varieties 
Varieties of butternut available in Kenya
•    "Butternut 401". It has resistance to powdery mildew
•    "Bugle". It has resistance to powdery mildew.
•    "Early Butternut F1". It has resistance to powdery mildew.
•    "Ultra F1". It has resistance to Fusarium wilt and powdery mildew.
•    "Waltham". It has resistance to powdery mildew.
Seeds of the above listed varieties are available at the major seed companies in Nairobi (e.g. East African Seed Company Ltd., Amiran Kenya Ltd. and Simlaw Seeds Co. Ltd)

Curcubita maxima is an annual vine climbing by lateral, 2–5-branched tendrils, strongly branched. It is a fast-growing plant that can reach up to 10 meters in length. Stems: rounded stems that are long running and softly pubescent. Leaves: alternate ad simple lobed leaves that are rough to the touch. Flowers: yellow flowers of the plant are quite large and showy. Fruit: large, globose to ovoid or obovoid berry that weighs up to 50 kg with a wide range of colors (orange, green etc.), has a thick, hard rind enclosing the pulp and seeds. Seeds: flattened, white to pale brown, surface smooth to somewhat rough, margin prominent. Many cultivars of C. maxima that exhibit various morphological and physiological characteristics exist across in Europe and Africa. The plant prefers warm temperatures and well-drained soil and is often grown in gardens and small farms. 
C. maxima is used as a food source, the mature fruits, leaves, flowers and seeds are used as vegetables. In addition to being grown for its fruit, the species is also grown for its leaves, which are highly nutritious and have a variety of culinary uses. The leaves are regarded as a bit coarse and of lesser quality than those of Cucurbita moschata, although this disappears in cooking. They are used fresh and in some locations dried for use during the off-season. Curcubita maxima is native to South America, perhaps the area around N. Argentina, Chile and Bolivia. It has been introduced into most tropical and sub-tropical countries of the world. In Cameroon, Nigeria and other western African countries, seeds are commonly roasted and salted, or ground into a thick paste that is mixed with vegetables in cooking.
(Chigumira Ngwerume, F. & Grubben, G.J.H., 2004).

Cucurbita pepo is an annual, scandent herb, climbing by lateral, 3–4-branched tendrils, strongly branched, or with bushy habit and then often without tendrils; Stems: angular and often grooved, prickly hairy. Leaves: alternate, simple, without stipules. Flowers are yellow to orange and unisexual. Fruit: are large, globose to ovoid, obovoid, cushion-shaped or cylindrical berry, weighing up to 50 kg when mature, with a wide range of colours, with small, raised, wartlike spots or smooth, sometimes deeply grooved. Flesh: soft, whitish to yellow or orange, many-seeded. Seeds: obvoid, flattened, usually white 
Principal features distinguishing Cucurbita pepo from other cultivated Cucurbita species are more deeply lobed leaves with silvery markings, prickly hairy stems and leaves and fruit stalk hard and pentagonal in cross-section. Cucurbita pepo tolerates monthly average day temperatures of 18–28°C, but growth is best when day temperatures are between 24°C and 29°C and night temperatures between 16°C and 24°C, as found at high altitudes in East Africa or at higher latitudes. Production is mostly restricted to the beginning of the dry season, when temperatures are relatively low and the pressure of aphids less intense. C. pepo is less adapted to tropical lowlands than C. moschata, especially during the rainy season. The young leaves and shoots are used as a potherb e.g. in south-western Nigeria, but in general the leaves of Cucurbita moschata are preferred, being less coarse. C. pepo included important vegetables such as Zucchini (courgettes), pumpkins, acorn squash, yellow squash, pattypan squash (scallop squash), etc.
Male flowers of courgette are sometimes used to make fritters. ‘Vegetable spaghetti’ cultivars are a speciality; when cooked the flesh of mature fruits resolves into thin strands which look like spaghetti. Cucurbita pepo seeds are edible in the same way as those of other cucurbits, either raw or roasted. Cucurbita pepo is less heat resistant than Cucurbita moschata and for that reason less appropriate for tropical Africa, yet it is grown on a limited scale in all countries (Messiaen & Fagbayide, 2004).

Ecological conditions

Pumpkins and squashes (various Cucurbita spp.) are grown in the tropics from the lowlands up to 2500 m altitude. They are warm-season crops adapted to monthly mean temperatures of 18-27°C. C. maxima is the most tolerant of low temperatures, C. moschata and C. argyrosperma the least, with C. pepo intermediate. C. maxima and C. pepo have long been cultivated in temperate regions. Butternut appreciates part shade in very hot conditions, such as can be obtained when intercropped with other crops or grown under fruit trees. 

Pumpkins and squashes respond very well to medium to heavy applications of compost or well- decomposed manure. They can be cultivated on almost any fertile, well-drained soil with a neutral or slightly acid reaction (pH 5.5 to 7). They are drought-tolerant, requiring relatively little water, and are sensitive to waterlogging. Excessive humidity is harmful because of the development of leaf diseases, so none of the species do well in the humid tropics. 

Agronomic aspects

Pumpkins and squashes are grown from seed. Seeds may be sown in containers and transplanted to the field when they are 10 cm high. Direct seeding of 2 to 3 seeds per hill is commonly practised. Trailing types are planted at distances of 2-3 m either way; the seed requirement is 2 to 3 kg/ha. The bushy types (mainly C. pepo) are planted closer, for example, plants spaced 60 to 120 cm in rows 1 to 1.5 m apart; the seed requirement is 3 kg/ha for pumpkin and 7 kg/ha for summer squash (C. pepo). Do not use seeds from plants where edible pumpkins and ornamental gourds are grown close together. Offspring will be bitter or even inedible.  

Husbandry
Sole cropping is sometimes used for commercial production. Pumpkins and squashes are also planted in home gardens or mixed with field crops such as maize. Cultural practices to improve growth and development include the removal of growing tips (in trailing varieties) to check growth, and the bagging of fruits in paper to protect against fruit fly and other pests. Fruit setting may be stimulated by manual pollination. The fruit may rot when in contact with moist soil, so often cut grass or leaves are placed beneath the fruit. 

Harvest, post-harvest practices and markets

Harvest
Winter squashes and pumpkins are picked when mature in a once-over harvest or in several rounds, about 90 to 120 days after planting depending on variety. When grown as leaf vegetable, usually the third and fourth leaves are harvested, while the tip and second leaves are left to grow. Young leaves and shoots are picked when needed. Pumpkins are considered to be among the most efficient of vegetable crops when evaluated on nutritional yield in relation to land area and labour needed. Indicative figures for seed yield of C. pepo are 400 to 1500 kg/ha. A valuable source of oil and protein is thus neglected if the seeds are left unutilised. In seed production, isolation between fields of different Cucurbita species is recommended, not only for reason of purity but also for obtaining maximum yields (pollen of other species may cause reduced fruit set).
Post-harvest practices
After harvesting pumpkins should be handled carefully to avoid bruising or damaging the skin. Use soft padding or cloth when transporting them to prevent scratches. Gently wipe off any dirt or debris using a soft cloth or brush. Avoid using water, as excess moisture can lead to decay. Mature pumpkin fruits can be cured in the sun, or under controlled conditions of 27-29 °C and 80-85% relative humidity for 10 days. This helps toughen the skin, extend shelf life, and enhance flavor.
Store pumpkins in a cool, dry, and well-ventilated area. The ideal temperature is around 10-13°C. Avoid direct sunlight, as it can cause them to deteriorate quickly. Ensure that pumpkins are not touching each other during storage to prevent potential rot from spreading. If harvested and stored properly, pumpkins can last for up to 3 months and in some cases 7 months. The pumpkin flesh can be dried in strips and reserved for soups and stews. While eating the fruits, people usually remove seeds; some are kept for planting later, and others are used as food.
(PROSEA, 2016, Chigumira Ngwerume, F. & Grubben, G.J.H., 2004)

Markets

Pumpkins have a vast market, both locally and internationally. Qualities sought after in the markets include: Size and color consistency, along with a healthy appearance, Blemish-free skins, vibrant colors, and uniformity in shape contribute to a pumpkin's marketability. Moreover, taste, texture, and overall freshness play a crucial role in consumer preferences.
The countries with the highest volumes of production in 2021 were China, India and Ukraine, with a combined 50% share of global production. 
Countries with the highest volumes of consumption in 2021 were China, India and the United States, together comprising 51% of global consumption. Ukraine, Russia, Bangladesh, Italy, Turkey, Indonesia and Algeria lagged somewhat behind, together accounting for a further 19
Pumpkins are grown for processing and fresh for ornamental sales. Local farmers' markets, grocery stores, and supermarkets are common retail outlets. Online marketplaces have also gained popularity, offering convenience to consumers seeking fresh produce. Additionally, food processing companies purchase pumpkins for canned products like purees and soups.

Further reading: https://www.indexbox.io/store/world-pumpkin-squash-and-gourds-market-report-analysis-and-forecast-to-2020/

© S. Kahumbu, Kenya

Nutritional value and recipes

Pumpkin is a healthy, versatile vegetable loaded with a variety of nutrients, including fiber, vitamins, minerals, and antioxidants. The fruits are low in calories but rich in vitamins and minerals, which are found in its seeds, leaves, and Flesh. 
Pumpkins are a good source of dietary fiber, supporting digestive health by promoting regular bowel movements and preventing constipation. Pumpkins contain potassium, which is important for maintaining fluid balance, muscle function, and blood pressure regulation. They also provide smaller amounts of other minerals like calcium, magnesium, and iron.
Pumpkins are a good source of vitamins A and C. Vitamin A is essential for maintaining good vision, a healthy immune system, and skin health. Vitamin C is an antioxidant that supports the immune system and skin health as well.
Pumpkins are loaded with antioxidants like beta-carotene, which gives them their vibrant orange color. Beta-carotene is converted into vitamin A in the body and is known for its potential to protect cells from oxidative stress and reduce the risk of chronic diseases. The high levels of beta-carotene in pumpkins are beneficial for maintaining good vision. Beta-carotene is a precursor to vitamin A, which is essential for the health of the retina and overall eye health.
 (Healthline (n.d), WebMD (n.d)
Table 1: Proximate nutritional value 100g edible portion

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.

*The specific Pumpkin species is unknown.

^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.