When you grow twin fruits in limited space (tub / drum), you must be careful about the supply of food and water. Some fruits may be lost in hostile weather but lack of food and water will never result in proper results and excess drinking water is also a threat to the plant.
In the case of fruit bearing trees, vermicompost twice a month, two to three handfuls depending on the size of the tub and once in two months, the bone meal (in certain cases) is applied to the soil at the very edge of the tub. In case of watering, the soil in the tub should not be allowed to dry out completely, even if the amount is small.
It is better not to use chemical fertilizers directly. It can be decomposed with soil separately and then used as required.