While the gift of the Fruit of the Spirit is pure grace (the un-earned and undeserved favor of God), we can cooperate with it.
In keeping with our agricultural metaphor, we must water the landscape of our soul. “Since the beginning of the world, water, so humble and wonderful a creature, has been the source of life and fruitfulness. Sacred Scripture sees it as "overshadowed" by the Spirit of God: At the very dawn of creation your Spirit breathed on the waters, making them the wellspring of all holiness” (from Catechism No. 1217, and the blessing of water at the Easter Vigil). The way we spiritually water our lives is with the Word and Sacraments - the primary sources of the life of grace for the Christian. They are our continual source of life, refreshment, and fruitfulness. To not take advantage of every opportunity to participate in them (either directly or by witnessing them at ordinations, baptisms, anointing of the sick, etc.) is to neglect the greatest sources of life God has gifted to us.
What’s great about this reality in the spiritual realm is there is never a danger of over-watering! We are, by nature, leaky vessels. We need to continually be filled with the Holy Spirit (Ephesians 5:18)).
For more reflection on this essential key to cultivating the Fruit of the Spirit, see Ps. 1; Ps. 65:9-10; Isaiah 58:11; Jeremiah 31:11-12.
The second way we can cooperate with and cultivate the Fruit of the Spirit in our lives is by providing good soil. We are all familiar with this imagery from the Parable of the Sower in the Gospels (Matthew 13; Mark 4; Luke 8). When God (the Farmer) sows the seed of His Spirit into our lives we must provide the proper conditions for it to grow and flourish. In Jesus’ time, a farmer would broadcast (scatter) the seed across large shallowly plowed fields that would often be traveled across by people and animals and quickly eaten by birds of the air. For maximum fruitfulness, the soil must be “receptive” and welcome the seed within. I like how James puts it, “Therefore put away all filthiness and rank growth of wickedness and receive with meekness the implanted word, which is able to save your souls” (James 1:21). The word meekness is rooted in the concept of humility which takes its origins from humilis or humus which means the soil or earth. To provide the proper spiritual soil we must possess a receptive and teachable spirit. God provides the seed (2 Cor. 9:10) and we receive it with hope and expectation.
The third way that we can cultivate the Fruit of the Spirit in our lives is by carefully pruning our spiritual garden. Again, the imagery is a common one in the Bible (turn to the opening verses of John 15 to reflect more deeply on this metaphor). The Greek word for pruning is katharos which literally means to “be made clean.” God is not only asking us to clear away the works of the flesh in our lives but also to be cleansed of all the painful memories and events of our lives that may be preventing us from fully flowering as the tender planting of the Lord.