The usual clove nursery consists of raised beds, 1.2-1.5 m wide, with paths 0.6 m wide, arid with semi-permanent shade raised about 2 m above the beds, which facilitates working beneath.
The average rainfalls for Zanzibar, 6 S, Pemba, 5 S, and the clove-growing areas in the Malagasy Republic on the small island of Sainte Marie at 17 S and at Tamatave on the east coast of the mainland at 18 S. Many of the clove-growing areas of Zanzibar Island have a higher rainfall than Zanzibar Town and often have 1 800 mm per annum or over, while some areas of Pemba may reach 2 000 mm per annum. The higher rainfall of Pemba, as well as the soils and configuration, are better suited to cloves than Zanzibar. The heaviest rainfall of Zanzibar, the masika season, falls during the months of March to May, during which the crop is usually planted.
Cloves are usually propagated by seeds. Under primitive conditions of culture the common practice has been to transplant self-sown seedlings, which may be found in great numbers in clove plantations which were not thoroughly harvested the previous year.
In their original home, cloves grow on small volcanic islands in the Moluccas. In Zanzibar the best soils for cloves developed in situ from limestone or mottled clays and sandy clays derived from deposits originating in the neighbouring mainland of Africa. The soils are often very acid with a pH value as low as 4.5. The fertility of the soils largely depends on the extent of leaching and on the mineral constituents of the original parent material, some of the soils being relatively rich in potash, but of low phosphate status. The soils of Pemba are, on the whole, better than those of Zanzibar.
In Madagascar the baskets are made of plaited Pandanus leaves, which can still be retained when planting into the field. Black polythene bags are likely to be more widely used in the future; they should be provided with drainage holes, filled with a good potting mixture, and removed at transplanting.
Wigg (1940) and Tidbury (1949) give full and good accounts of nursery techniques. In Zanzibar the nurseries have been maintained by the government. The nursery should have an adequate supply of permanent fresh water, be close to a road, and the area to be transplanted and with materials for construction. The soil should be a loam of good structure, which will permit a ball of earth to be removed with the seedling at transplanting.