Late Season Fertilization
LATE SEASON FERTILIZATION
Late season fertilization is very important to deciduous fruits. In the early spring, when trees begin to flower and bloom, there is a high demand for nutrients; however, soil temperatures may still be below, so the roots may not be fully active and nutrient absorption from the soil may be slow. In this case, the supply of nutrients to developing flowers and leaves comes mainly from nutrients that were stored in the tree trunk and branches in the previous season. It is important to fill up these storages after harvest when there is no more demand for nutrients from the fruits so they can be available for the waking tree in the spring.
This is especially important in grafted deciduous trees where the scion (upper part) wakes up before the rootstock (the lower part). In these cases, the tree may go through blooming, flowering, and the fruit set before the rootstock is active and it will be completely dependent on last year’s storages in order to supply the high demand for nutrients for all these processes.
A good example can be seen in this picture from an almond orchard in Israel: an un-grafted peach rootstock wakes up and flowers long after the almond grafts around it bloomed, flowered, and set fruit.