(copying from discord discussion)
I like your ideas for penalizing the crudely tilled ground, Red Ram.
The problem that I have with metal hoes is that it requires a skill set previously learned in other games. The race to smelting is a strategy that has to be learned and perfected. Which is fine. Once it becomes second nature, players are eager for that pickax anyway, so waiting to plant their seeds is no big deal.
Also, as Airova mentioned, tools aren't even necessary for growing crops on a small scale. For game mechanics, it makes sense to require a tool; a crude stone age farming implement would be more in keeping with the rest of the game, and more realistic too.
So here is the catch (and this is probably only a hardship for single players): a player starts a game, and unless they've already perfected the race to smelting, or already know how to keep themselves armed and know how to hunt efficiently and cook their food, they are going to starve to death. Unless they start prepping to smelt pretty quickly, it's game over. Why can't we spend some time in the stone age and maybe struggle our way to copper?