How Hidden Grottos work
- Interact with suspicious paths behind trees to enter a Grotto.
- Grottos repopulate once per day. A Beckoning Bell can also refresh them (One is obtained for free in Ilex Forest from an npc, more can be farmed from Battle Factory after beating the third gym).
- A Hidden Grotto has a 60% chance to contain a Pokemon, a 32% chance to be a generic item such as Rare Candy, PP Up and such, and a 8% chance to contain a grotto specific item.
- Grotto Pokemon have two guaranteed 31 IVs and their Hidden Ability. Each of the four Pokemon in a grotto is equally likely to spawn when the grotto rolls a Pokemon spawn.
- The Grotto specific item listed below is one possible result and is not guaranteed.
Locations
Route 35 (Lv. 18)
Rookidee, 
Pikachu, 
Poltchageist, or 
Eevee.
Grotto specific item: Unremarkable Teacup.
Goldenrod Shore (Lv. 20)
Minccino, 
Shroomish, 
Own Tempo Rockruff, or 
Heracross.
Grotto specific item: Light Clay.
Route 38 (Lv. 30)
Munchlax, 
Male Meowstic, 
Female Meowstic, or 
Espathra.
Grotto specific item: Stardust.
