Seeds in the lives of people are crucial for the opportunity of major, positive change later on in life. If there is not a word of encouragement, a gesture of consideration or act of love toward anybody, especially unbelievers - how can anyone water each of those? How can someone come along and continue that seed of encouragement? How can anyone build upon that gesture of consideration? How can anyone maintain the abundance of God's love? The seed(s) must be planted first.
Paul writes to the believers at the church in Corinth, "the Lord has assigned to each his task. I planted the seed, Apollos watered it, but God has been making it grow." (Corinthians 3:5-6)
I personally believe every Christian is a Planter and every Christian is a Water-er. Which one God desires you to be is situational. Each priceless opportunity God places in front of us, we must diagnose quickly with sensitive, spiritual ears and then either Plant or Water. After our part is done, we continue to pray for them and God takes it from there - God makes it to grow. He is the one who nurtures the seed. He is the one who anoints the water with life-giving meaning and application.
Let me share Matthew 9:37-38 in reverse for the both of us -
"Ask the Lord of the harvest, to send out workers into his harvest field. [Why?] The harvest is plentiful but the workers are few." An issue in The Church right now is what to do about the few harvest workers or those willing to testify and share God's love in the hope of gaining another soul for God and His Heaven. The answer is right here in the same breath that is used in describing the problem - "Ask the Lord of the harvest to send out workers into His harvest field." The "field" is "His". What are we waiting for? I say we enlist as workers, if we have not already, as we ask the Lord to send out more workers.
I used to think there was some Denominational Formula for witnessing on the highways and in the hedges. In the right environment those have their places. However, many times I observe God's kindness, love, consideration and compassion flowing through me to others - to be an effective Seed. In addition, these Seeds are not only for unbelievers but Christians as well. Galatians 6:10 states, "Therefore, as we have opportunity, let us do good to all people, especially to those who belong to the family of believers."
One more important point is this cannot be seasonal. Just as Jesus has a heart for people and relationships everyday, so should we. Christians should actually pray for opportunities everyday to be The Planter Or The Water-er, God will do the rest.