The knowledge of God is compared to a seed which must be planted in order to grow. AT: "When I preached God's word to you, I was like one who plants seeds in a garden" (See: [[rc://en/ta/man/translate/figs-metaphor]])
As seeds need water, faith needs further teaching in order for it to grow. AT: "and when Apollos continued to teach you God's word, he was like one who waters a garden" (See: [[rc://en/ta/man/translate/figs-metaphor]])
As plants grow and develop, so faith and knowledge in God also grow and become deeper and stronger. AT: "but God caused you to grow" or "but just as God causes plants to grow, he causes you to grow spiritually" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here to give growth means to cause growth. The abstract noun "growth" can be translated with a verbal phrase. AT: "it is God who causes you to grow" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])