Care
Citrus are a genus of flowering trees and shrubs in the Rutaceae family, native to subtropical and tropical regions of south-East Asia. Today, some species are economically important in the Mediterranean basin, India subcontinent as well as in the south of the USA, where they find optimal soil and climatic conditions. Oranges, lemons, grapefruit, grapefruit and lime are fruit of citrus trees.
Soil
Citrus trees require between 60 cm and 1 meter of well-drained topsoil to grow optimally. Loams and sandy loams are preferred, a complement of humus is optimal. In the case of very sandy soils with low water-retention capacity, there is a risk of nutrient leaching. Clay soils can cause collar and root rot and the risk of tree death. Optimal pH is between 6.0 and 6.5 and pH above 8 should be avoided. Slopes of up to 15% are suitable if soil erosion and excessive drainage are avoided. Windbreaks are recommended
Climate
The species are happiest in warm, temperate areas but have some degree of resistance to frost (variable between varieties). Citrus tolerate high temperatures provided the soil moisture is optimal. Trees have some resistance to cold temperatures but in general they are not recommended in areas with heavy regular frosts. Resistance to frosts varies with variety, tree age and health. Young tree will be damaged by even very light frosts whereas an acclimated mature tree may tolerate temperatures down to -5° C for a short time. Trees under stress are more sensitive.