A typical harvest of grain in the time of Jesus would be a sevenfold to eightfold yield. A hundredfold yield of grain could not possibly be attributed to the skill of the farmer or the fertility of the land. Jesus' hearers would have understood that only the sheer grace of God could produce a hundredfold harvest.
Our approach to our daily reading of Scripture can resemble that of the Israelites who gathered the manna that God provided for decades in the desert (Ex 16:14ff). Many Israelites surely gathered it routinely year after year, seeing the miraculous food appear without perceiving, hearing others around them in the desert picking up their daily miracle from heaven without understanding (Lk 8:10). A normal routine of Scripture reading may not produce a hundredfold harvest, but rather the typical sevenfold or eightfold harvest that the word of God automatically produces "of itself" (see Mk 4:28). If, by our own efforts, we are truly open in our daily Scripture reading (Lk 8;15), perhaps we can jack up the harvest to thirty or sixtyfold (Mt 13:8).
We at Presentation Ministries write One Bread, One Body to encourage you to read the daily eucharistic readings while attending daily Mass. At Mass, we are in the environment of miracles. Day by day, let's place ourselves thankfully in the eucharistic presence of Jesus, open our Bibles, and expectantly ask Him to open our ears (Is 50:4). God will transform us into miraculously good ground, and we will see an astounding, miraculous, hundredfold or greater harvest.