How to Grow Soursop Trees The soursop tree can reach height of 30 feet and is soil tolerant, although it flourishes in well drained, sandy soil with a pH of 5-6.5. A tropical specimen, this low branching and bushy tree does not tolerate cold or strong sustained winds. It will, however, grow at sea level and up to elevations of 3,000 feet in tropical climes. A rapid grower, soursop trees produce their first crop three to five years from seeding. Seeds stay viable for up to six months but better success is met by planting within 30 days of harvest and seeds will germinate within 15-30 days. Propagation is usually through seeds; however, fibreless varieties can be grafted. Seeds should be washed before planting. Soursop Tree Care Soursop tree care involves copious mulching, which benefits the shallow root system. Overly high temps from 80-90 F. (27-32 C.) and low relative humidity cause pollination issues while slightly lower temps and 80 percent relative humidity improve pollination. Soursop trees should be irrigated regularly to prevent stress, which will cause leaf drop. Fertilize every quarter of the year with a 10-10-10 NPK at ½ pound per year for the first year, 1 pound the second, and 3 pounds for every year thereafter. Very little pruning is required once the initial shaping is attained. You should only need to prune out dead or diseased limbs, which should be done once harvest is over. Topping the trees at 6 feet will facilitate harvesting. 2 seeds