What comes first after you plant a seed — the stalk or the grain?
After a seed is planted, the stalk comes first, and then the grain follows. Paul uses this agricultural order to illustrate resurrection: the bare grain is sown, not the whole stalk, and the seed must die before it is made alive.
Les explains that Paul is talking about the mundane things of agriculture—whether sowing wheat, rye, corn, or some other grain. When you plant, you do not plant the whole stalk of wheat; you plant the seed, the bare grain, the individual kernel. It stands to reason that the seed does not suddenly come up above the ground. What comes first is the stalk, and then the grain. Paul uses that as a total illustration of our own resurrection experience: you do not sow what you expect to see, the whole stalk, but the bare grain. The context stresses that what is sown is not the body that shall be, except it die.
And that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other grain:
But God giveth it a body as it hath pleased him, and to every seed his own body.