rough lemon or sour orange to obtain strong root stocks (see also fruit tree propagation). It is often advisable to graft the plants onto rootstocks with low susceptibility to gummosis because seedlings generally are highly vulnerable to the disease. Useful rootstocks include wild grapefruit, cleopatra mandarin and tahiti limes. C. macrophylla is also sometimes used as a rootstock in Florida to add vigor. Climatic conditions and fruit maturation are crucial in cultivation of the lime tree. Under consistently warm conditions potted trees can be planted at any season, whereas in cooler temperate regions it is best to wait for the late winter or early spring. The Key lime tree does best in sunny sites, well-drained soils, good air circulation, and protection from cold wind. Because its root system is shallow, the Key lime is planted in trenches or into prepared and broken rocky soil to give the roots a better anchorage and improve the trees' wind resistance. Pruning and topping should be planned to maximise the circulation of air and provide plenty of sunlight. This keeps the crown healthily dry, improves accessibility for harvesting, and discourages the organisms that cause gummosis. Harvesting The method of cultivation greatly affects the size and quality of the harvest. Trees cultivated from seedlings take 4–8 years before producing a harvest. They attain their maximal yield at about 10 years of age. Trees produced from cuttings and air layering bear fruit much sooner, sometimes producing fruit (though not a serious harvest) a year after planting. It takes approximately 9 months from the blossom to the fruit. When the fruit have grown to harvesting size and begin to turn yellow they are picked and not clipped. To achieve produce of the highest market value, it is important not to pick the fruit too early in the morning; the turgor is high then, and handling turgid fruit releases the peel oils and may cause spoilage. Postharvest process Shelf life of Key limes is an important consideration in marketing. The lime still ripens for a considerable time after harvesting, and it is usually stored between at a relative humidity of 75–85%. Special procedures are employed to control the shelf life; for example, applications of growth regulators, fruit wax, fungicides, precise cooling, calcium compounds, silver nitrate, and special packing material. The preferred storage conditions are temperatures of and a humidity over 85%, but even in ideal conditions post-harvesting losses