Holodrum
Horon Village
1. Burn down the sapling west of the Maku Tree.

Eastern Suburbs
1. Change the season to winter to reach the upper-level Windmill entrance.

Woods of Winter
1. Once you have the Power Bracelet (or flippers), you can reach the Piece of Heart southeast of the Snake's Remains.

Eyeglass Lake
1. Change the season to summer to dry out the large pool of water just east of the lake. Pick up a rock, then go down the stairs to find a Piece of Heart.

Ruined Keep (Moblin's Keep)
1. Defeat the Moblin King.

Mt. Cucco
1. In spring, use a Blast Bloom to reach a Piece of Heart right in front of Dancing Dragon Dungeon.

Spool Swamp
1. Change the season to spring, then jump in the water. The current will lead you to a Piece of Heart.

Graveyard
1. After you've gotten Roc's Cape, go through the cave at the Western Coast in autumn. You can now pick up the mushrooms blocking the way to the Piece of Heart next to Explorer's Crypt.

Temple Remains
1. After you've changed the layout of the Temple Remains, you can reach a cracked wall. Bomb it and go inside to get a Piece of Heart.

1. Maple will drop a Piece of Heart at Random, so run into her as often as possible.
2. Eventually, you will get a Piece of Heart from a Gasha Nut.

Subrosia
1. Go to the Market and trade 20 pieces of ore and 10 Ember Seeds for a Piece of Heart.