How do I get the Harvest Ability in sun and moon?

Question

I know that harvest is a secret ability that exeggcute gets, but how do I obtain it? Same question for trevenant.

Answer 1

For hidden abillities, you need to make a sos chain. The higher the chain is, the more chance you will get a HA.

Answer 2

You can also get a harvest phantump although it is harder with it being a ghost but aside from having ghost type rather than dragon, they both share grass, but if you want a defensive wall, get exeggutor, if you want specially defensive, get trevenant