When he converts the EC, what color does it convert to?
The default (unless it's changed in DNF) is that converts make the converted card their own Brigade. That would mean Sower converts to Gold regardless of the Enhancement's color (unless you Gold Shield him to a different Brigade, in which case you can run around Converting people to any Brigade).
So Sower can place any brigade good enhancement or does it have to be a gold brigade?It seems to me that he could place any brigade enhancement, but it still converts the EC to good gold.
Because the card with the convert ability (Sower) is gold brigade. If the brigade is not specified, then the default is to convert to the brigade on the card with the convert ability.
On an earlier draft of Sower, he converted to a brigade on the enhancement. That was removed to save space. So, it converts to the brigade of Sower.