A plant of the moist tropics, it can also be grown as an annual crop in the temperate zone as long as it can be given a growing season of at least 4 months. It grows best in areas where annual daytime temperatures are within the range 20 - 30°c, but can tolerate 10 - 40°c[418 ]. It is not tolerant of frosts[418 ]. It prefers a mean annual rainfall in the range 1,200 - 1,600mm, but tolerates 800 - 4,000mm[418 ]. An easily grown plant, it succeeds in most moderately fertile, well-drained soils when growing in a sunny position[1 ]. A soil too rich in nitrogen will encourage leaf growth at the expense of flowering, and so will reduce the yield of fruit[418 ]. Prefers a pH in the range 5.5 - 7, tolerating 4.3 - 8.5[418 ]. Young plants grow rapidly and flowering starts from 40 - 100 days after sowing. As the first flowers are initiated, branching and subsequent production of smaller leaves occurs[299 ]. Growth and flowering may continue indefinitely, but are suppressed once sufficient fruits have set[299 ]. The preferred weight for fruits of Gilo Group and Kumba Group is 30 - 40g. One plant may produce from 500 g to about 8 kg of fruits, depending on the cultivar and growing conditions[299 ]. Without irrigation, yields are 5 - 8 t/ha, and with irrigation 12 - 20 t/ha. Improved cultivars grown under favourable conditions may yield 50 - 80 t/ha[299 ]. Fruits of Kumba Group have mean weights of 70 - 120 g, sometimes even over 200 g; yield is 10 - 20 t/ha[299 ]. Under good management, farmers growing cultivars of Shum Group can get up to 75 leaf bundles of 30 kg each per 100 m2. This means that the crop has a yield potential of 225 t/ha. The average leaf yield during the dry season for a once-over harvest, however, is only 30 t/ha[299 ]. This is a food crop that is difficult to characterize as a whole, with a great plasticity and grown in a variety of habitats ranging from dry rocky outcrops and grasslands to forests[308 ]. Because of their morphological diversity, various cultivars of S. Aethiopicum have previously been described as many different species, and have been confused with S. Incanum and other species. Four cultivar-groups are now recognised, as follows:- S. Aethiopicum Gilo Group. The fruits, which are like hens' eggs or many other shapes and sizes, and scarlet when ripe, are eaten unripe, cooked in stews or even raw[317 ]. Plants in this group thrive in full sun in woodland savannah on fairly deep and well-drained soils with pH 5.5 - 6.8, and in temperatures of 25 - 35°c during the day and 20 - 27°c at night[299 ]. S. Aethiopicum Shum Group. Grown in tropical Africa, especially in Cameroon and Uganda. The glabrous small-leaved shoots are cooked as spinach. This group thrives under warm, humid conditions and will drop their leaves when it gets dry. In Uganda they are grown in drying swamps during the dry season[299 ]. S. Aethiopicum Kumba Group. Grown in sub-Sahelian W Africa, especially Senegal, in the wet season. The large glabrous leaves are cooked as spinach: subsequently the large, sweet, ribbed fruits are eaten raw or cooked in stews[317 ]. This group thrives in very hot conditions, with temperatures up to 45°c during the day and air humidity sometimes as low as 20%, especially if they are irrigated[299 ]. S. Aethiopicum Aculeatum Group. These prickly ornamental plants with attractive but very bitter scarlet fruits possess some disease resistance so they are used for breeding and as rootstocks for S. Melongena in Japan[317 ]. There are some named varieties in in Shum and Gilo groups[300 ]. The bitter and small-fruited, prickly and hairy ancestor, S. Anguivi occurs throughout tropical Africa[317 ]. Slugs really love the young plants and will totally destroy them if given half a chance[K ].