Jesus does not only emphasize the difference between the small beginning and the great result (from seed to tree), but also the fact that the seed is sown, put into the ground. Thus, God’s kingdom begins with something you do not expect, namely, a seed in the ground. That seed itself is already very tiny and is also tucked away in the ground. The seed must die. The seed is like Jesus himself who is first humiliated, despised, and given up to the earth (buried) before any fruits come to his work.
32 yet when it is sown it grows up and becomes larger than all the garden plants and puts out large branches, so that the birds of the air can make nests in its shade.”