Jack performs well in humid regions upto an elevation of 1000m. Deep, well drained soils are ideal for jack cultivation. Any rise in water table or poor aeration of the soil is detrimental to the crop.
Jackfruit differs in size, shape and quality. It may be classified into 2 groups:
(i) soft fleshed(koozha) and (ii) firm fleshed(varikka). The firm fleshed type is highly tasty, sweet and crisp. The 2 groups are further classified depending on the taste, size of fruit, odour of flesh, nature, shape and diversity of prickles on the rind.
Seedlings or grafts can be used for planting. For grafting, raise seedlings in polythene bags and when they are 9-12 months old do inarching. One month after grafting, behead the root-stock above the graft joint.
Epicotyl grafting can be undertaken successfully in jack. 3-4 month old, 10cm long scions are grafted on 5 day old rootstocks in polythene bags by the cleft method during the month of June and kept under moist conditions. The scions should be pre-cured 10 days before grafting by clipping the leaf blades and keeping the petioles intact on the twig. The graft union is complete by 80 days after grafting operations.
It can be planted at the onset of monsoon showers. Seedlings or grafts are planted in pits of 60x60x60cm size at a spacing of 12-15 m. Refill pits with mixture of topsoil and 10kg compost or FYM per pit to a level higher than the adjoining ground. Plant the grafts in the same depth as they were in the containers, preferably in the late evening. Deep planting results in poor growth of the graft. Ensure that the graft joint is above the soil level. Stake the grafted plants to prevent snapping at the graft joints.
Excellent drainage and adequate watering need to be ensured. At no stage it should be exposed to drought and frost. It is useful to provide some protection, especially to young trees. Jack is rarely manured. Even without fertilizer application, the jack trees come up well under Kerala conditions.
Shoot borer caterpillars & Jack scale : Spray Ekalux 25% EC @ 0.05%
Mealy bug: Spray lime sulphur or dust sulphur.
Pink disease, Stem rot, Fruit rot, Budrot : Pruning of affected plants and protecting the cut- ends with Bordeaux paste are recommended.
The seedling plants generally bear after 8 yrs and the grafted plants after 3 yrs of planting. The fruiting season lasts about 4 months from Jan-Feb to May- June. The average yield from one tree is about 50-100 fruits per year.