Golden Seeds are special items that allow you to increase the number of charges of your sacred flasks (Flasks of Crimson Tears / Flasks of Cerulean Tears). With a few exceptions, you'll find seeds near small golden erdtrees.
The number of seeds needed for subsequent upgrades gradually increases, starting with 1 and ending with 5 seeds. In total, to upgrade your flasks to the maximum level (14 flasks), you need 30 seeds. You can find a few more seeds so you don't need to collect them all.
After finding a golden seed, go to any "Site of Grace", then in the "Flask" menu choose "Add charge to flask".
