Is there a harvest of crops before the main harvest? I was thinking that some seeds might mature prematurely?

Question

I seem to remember that the very first output was of a lesser quality or was not enough to sell.

Answer 1

There is such a variety of "crops" that your question is imprecise. Fruits and vegetables are commonly "picked over" more than once with only the ripe being taken.
For seed crops like wheat, maize, barley, etc., it is likely that anything maturing early is going to be sparse and trying to get it out of the field is going to damage the rest of the crop. So seeds are breed to mature at the same time.