Upgrading Soil Level

[BD5 Racoon]

So I bought the book, and bought the upgrades... Is lvl 20 the max you can buy with gold?

[Iyasenu]

Yes, you can't buy any more than Lv20 with Gold Bars.

Any more is going to have to come from resident work/hobby boosting the Soil skill, such as Farming or Gardening.

[Liq]

My Meadow is 24 but It reads base 20 +4
I'm guessing that's coming from either the farmers or the fertility trait, not sure which or because I made a maid out of Loytel as soon as I got the gold bars and spent gold on expanding the map tiles before I did any serious work on the map.

Vernis on the other hand says 0 +10 but it's tiny compared to meadow and it's a mining town ( t's still my crim drug farm). IIt has no fertility trait, no expanded land and only a couple of farmers that are not actually farmers , just people with the farming as work.

So in the end I have no idea. other than yes, it seems 20 is the max base value

[Helios]

If you make someone a maid you can also ask them to expand the land giving even more fertility.