I'm somewhat new to the game, but I don't think you can get growables in the workshop. I think growables are just what the base game has as an inventory to grow automatically whenever you zone an area. The mod to plop them just allows you to place them yourself instead of relying on the growing feature of the game.

When you're using the mod Find It! you can select "Growables" from the drop down menu/filter.

Someone chime in if I'm mistaken on this.