Now he that planteth and he that watereth are one: and every man shall receive his own reward according to his own labour. 1 Corinthians 3:6,8
In Palestine and Syria plowing, planting and watering are each done by different people. The country is mountainous and fields are difficult to plow, especially in Judea where the fields are merely small terraces on slopes and on the mountain sides. Plowing is done with oxen. It takes an expert to handle the plow and direct the oxen. Generally this type of work is done by elderly and experienced men.
And it is only the older men who know how to scatter the scanty seed and plant the crops. Indeed, this type of work cannot be entrusted to the care of young men.
Watering is not considered a difficult task. It is done by younger men and women. The crops are watered once a week. Planters receive higher wages than those who water the crops.
Paul had planted the seed of the Christian gospel in many cities in Asia Minor and Macedonia, and Apollos had watered it. But then the seed was entrusted to God, who guards it and causes it to grow.
Paul denounces the idea that he and Apollos and Peter were building on different foundations and that they were at variance with each other. They were entrusted with different tasks, but they were building on the foundation which was laid down by Jesus Christ, who is the builder of the House of God.
(Lamsa, George M. 1945. New Testament Commentary. Philadelphia: A.J. Holman Company., p. 239-240)