Powerberries (GBC)

From Harvest Moon - Wiki on Neoseeker

Whenever you find and eat a Powerberry your overall stamina will increase. There are ten in all. Check your flower box to see how many you have. You have one flower for each berry you've eaten.

1. Given by the Harvest Sprites after you give them some mushrooms.
2. Till the soil behind your woodbox.
3. Till by the watering pond.
4. Till by the watering pond.
5. Till the south-east area of your farm before you get a field upgrade.
6. Till south-east area after field upgrade.
7. Till the north-east area after field upgrade.
8. Use the pick axe on the stone room in the cave.
9. Hit the wall between the lights six times. This is in the pick axe room. Afterwards, look under the rocks to find two Powerberries.