This one is kind of confusing:

The quest "Opening Nolbu's Gourd" has the prerequisite quest "The Lost Seed". Once you complete "The Lost Seed" you are given a magic seed to use for "Opening Nolbu's Gourd" quest. But if you accept the "Opening Nolbu's Gourd" quest from the NPC Nolbu and then forfeit it, the NPC Nolbu won't offer the quest again. Then if you throw away or lose the magic seed, you can't get another one from the Swallow NPC that gives you the seed for completing the quest "The Lost Seed" to begin with.

So now the "Opening Nolbu's Gourd" quest is just soft locked. The NPC Nolbu won't offer the quest because I don't have the magic seed, and the Swallow NPC won't offer to give me another magic seed to replace the one I lost.

Unless I'm missing something, I can't seem to figure out how to get another magic seed.