Traditionally, cashew crop is propagated by seed despite its high heterozygous genetic nature. Trees grown from seeds do not resemble their mother plant; they greatly vary in both agronomic and economic traits. Because of this variation some used different traditional propagation techniques in order to eliminate the agronomic and economic distinction of cashew trees. Propagation method includes air and ground (stooling) layering; side and wedge/cleft (tip) grafting; patch and chip-budding, and cutting methods.
The cashew is a strong plant that is renowned for growing in soils, especially sandy soils, that are generally unsuitable for other fruit trees. For the best production deep, well-drained sandy or sandy-loam soil is recommended. Cashew trees will not grow in poorly-drained soils.
Self-pollination and cross-pollination play an important role in the formation of cashew seed. Seedlings therefore show great variation and no "true to type" trees can be grown from seed.Selected trees should preferably be multiplied by grafting or air layering because vegetative propagation will ensure the best production and quality. Trees that are precocious bearers and grow vigorously are selected.
Fresh seeds that sink in water are planted in an upright position in a planting bag containing a loose, sterilised soil mixture. Three to four seeds can be planted directly in the planting hole. The weakest ones are thinned out later and the strongest left to develop further. The seedlings are very susceptible to Phytophthora root rot. The plant bags should be 350 to 400 mm deep, as the tap-root grows very fast and bends around as soon as it touches the bottom.
Cashew seedlings are grown under shade (45 %) and hardened off before planting in the orchard. It is very important not to disturb the root system during planting. Young trees should be supported for the first 2 to 3 years so that wind will not blow the plants over.