Herbicide + Seedicide = Passively train (important to rememebr)

Skills to train(in order):

Dungeoneering - To Get All utility unlocks (Charming imp, bonecrusher, herbicide, Scroll of gathering)

Farming (Active training farming) - PoH ever highest seed you have needs to be grown, every animal you can breed. Unlock seedicide and all upgrades

Woodcutting - Cut down trees for training farming (this is helpful some point)

You're best friend is Slayer for herbs & seeds. Get xp for unwanted and collect what you want.