Most of the best citrus commercial varieties do not reproduce true by seed; they must be propagated through grafting.
These commercial varieties are grafted onto rootstock of a specie known to give good results in terms of high growth vigour, compatibility with other varieties and adaptable to various soil conditions. The seed commonly used for raising citrus rootstock is the rough lemon (sour lemon). Budding is the most preferred method of citrus grafting.
When the rootstock plants of the selected rootstock are one year old or come to a buddable stage, the bud of a desired scion variety is budded at a height of about 25–30cm from the ground level. To ensure good budding success, the budding is done during the months of active growth or when there is good sap flow in the plants. Thus, budded plant should be immediately irrigated. Bud wood of the scion must be taken from virus free indexed plants so that healthy, productive and true-to-the-type are produced.
The season A is the best time for transplanting. Planting holes of 0,8 x 0,8 x 0,8 m are prepared and the soil mixed well with 50 kg of organic manure.
The young trees are planted to the same depth as they were in the nursery. Once the tree has been planted, the soil must be firmly tramped down. A basin for irrigation is made around the tree which must be thoroughly irrigated immediately after planting. Irrigate again the following day to seal any cracks in the soil.
Spacing is chosen in relation to several factors: rootstock, climate, soil, cultural practices. Citrus trees can be planted at 4m x 4m or 3m x 5m spacing to accommodate as many plants as possible per unit area.
Planting depth is critical to the survival of citrus trees. The rootstock is somewhat resistant to foot rot disease, but the top is quite susceptible. If the bud union is too low with respect to surrounding ground, the tree could contract foot rot and die. The practice of scooping out grass and soil to form a large depression for ease of watering almost guarantees the death of a citrus tree.