To grow Peanuts or Herring, you'll need to upgrade your fields:
On a level 1 field, you can plant basic crops like Oranges (Tropical Island) or Flax (Nordland Farm).
Once you upgrade the field, additional crops become available, such as Peanuts or Herring, depending on which farm you're on.
Where can I find all available seeds?
Tap the blue information ("i") button in the bottom-left corner when selecting a field. There, you’ll see a complete list of which seeds unlock at which field level.