Q:

Can "to seed" and "to sow" be used interchangeably?

I'd never heard about "to sow" until recently, and I was quite surprised that I couldn't find even a connotation about the difference in meaning from "to seed."
The German word "säen" is translated with both "to seed" and "to sow", neither of them are marked dialect or old-fashioned or anything.
Wiktionary defines them as:

to seed: To plant or sow an area with seeds.
to sow: To scatter, disperse, or plant (seeds).

As a non-native speaker, I fail to see the difference here (especially when one is defined using the other).
In this sense, can they be used interchangeably?

A:

No, they can't always be used interchangeably. To sow seeds is to put or spread them where you want them to grow, or you can speak of sowing a particular type of plant. You can seed a patch of ground (sow seeds on it), but 'seed' as a verb can also mean to produce seeds (of a plant), to remove the seeds from a fruit, as well as the various metaphorical uses mentioned by user067531. 

A:

I think that one main difference is the financial/tech usage of seed vs sow:

Transitive To seed (Wiktionary) :

To start; to provide, assign or determine the initial resources for, position of, state of.
A venture capitalist seeds young companies.
  The tournament coordinator will seed the starting lineup with the best competitors from the qualifying round.
  The programmer seeded fresh, uncorrupted data into the database before running unit tests. 

The usage in sports, especially in tennis, is also worth mentioning.

To be able to compete (especially in a quarter-final/semi-final/final).
The tennis player seeded into the quarters+tennis.   

Sporting (originally tennis) sense (1898) is from notion of spreading certain players' names so as to ensure they will not meet early in a tournament. (Etymonline)

A:

I would just point out that while you can "sow the seeds", you should not "seed the sows".

