During the course of The Legend of Zelda: Skyward Sword HD, Link will have to not only save the world from a great evil, but also help the common people solve their problems. These small side quests are not mandatory to complete the game, but the rewards you can get by completing them make it worth the effort.
Here’s how to complete the Plow Needed side quest and what you get for doing so.
How to Complete the Plow Needed Side Quest in The Legend of Zelda: Skyward Sword HD
The Plow Needed side quest becomes available right after finding Kukiel and defeating the Imprisoned for the second time. Once this has been accomplished, talk with Kina near the Lumpy Pumpkin to start the side quest.
After learning from Kina that she needs some help tending to the pumpkin field, you need to head over to Eldin Volcano. Land on the East Bird Statue, turn left down the path, jump on the geyser, and then dive inside the volcano. Here you will find Guld on the highest platform: speak with him and pick the I know the place! option. Fi will transport Guld to the pumpkin field near the Lumpy Pumpkin: head over there yourself, speak with Kina to receive 5 Gratitude Crystals, and complete the side quest.