After completing the Lanayru Mining Facility, return to Skyloft. At night, enter Fledge’s room in the Knight Academy to learn that he wants to become stronger. He can currently only do a few push-ups, but he thinks that if there was some sort of potion that could give him stamina, he would be able to improve rapidly.
Head over to the Bazaar during the day to buy a bottle of the newly concocted Stamina Potion from the Potion Shop for 50 rupees.
Go back to Fledge’s room at night, and give him your bottle of Stamina Potion. He thanks you and continues to train, encouraged by your support.
Return to Fledge’s room after finishing the Ancient Cistern, and you will see that he has made great improvement. He has gone from under 10 push-ups to over 50. However, he still is not satisfied.
Buy a second Stamina Potion at the Bazaar, and bring it to Fledge at night so that he can become even stronger. He continues to train, and asks you to return soon so that you can see his success.
Receiving the Gratitude Crystals
After finishing the Sandship, visit Fledge’s room once more to witness his incredible transformation. He is doing nearly 4000 push-ups as a warm up! He might be stronger than Link! Fledge will then thank you for your encouragement and reward you with 5 Gratitude Crystals. In addition, the Pumpkin Pull minigame is now unlocked.