Let's get one idea into our heads.

We are going to have this chap writing books one of these days." Ideas are never born; they are suggested; they are planted seeds.
Ruth did not reply, but stared past the doctor, her eyes misty.

The doctor had sown a seed, carelessly.

All that he had sown that afternoon with such infinite care was as nothing compared to this seed, cast without forethought.

Ruth's mind was fertile soil; for a long time to come it would be something of a hothouse: green things would spring up and blossom overnight.