غَرَسَ ... وَسَقَاهُ ... حَتَّى أَثْمَرَتْ أَعْمَالُهُمْ.
He planted, watered, and their deeds bore fruit.
Subsequent references to watering and fruiting reinforce the agricultural source domain. These source-associated details illustrate the effect commonly discussed under reinforcement of an istiʿārah (tarshīḥ).
Do not automatically count each later word as an independent instance of tarshīḥ. Ask whether it elaborates the initial borrowing, creates another figurative predication, or does both within an extended picture.