From GameRant: “After many long-awaited months, Nier Replicant has finally been released for fans to fans to enjoy. Aside from the main storyline, there are plenty of side quests in Nier Replicant that ask players to do all sorts of different tasks in the game.
One of these sidequests, the “Life in the Sands” mission, requires gamers to acquire ten Pink Moonflower seeds. Unfortunately, these seeds are not available for purchase in any shop, and must be earned through planting seeds in Nier Replicant.”
Source: N4G PC NieR Replicant: How to Get Pink Moonflower Seeds