If you fail with Gold protector, your item gets reverted to maximum 2 lvls lower than you had, sometimes even stays at same lvl. With Green protector it reverts your item to lvl 0.
Btw, you need lot of Seeds in game, so it is actually cheaper to buy them than get them by exchanging the seeds...
Also as far as I can tell you can get as many green as you want but only one gold protector per character from npc Jack then the option disappears. (1450 seeds required but they are tradable between your characters)
Comments
Have a taste of my Kameha-meha boom boom boom.,
Black Wizard
@ngxpmage
You can exchange "Seeds of dream" for Protector in Ardeca npc Jack - ~850 seeds for green one and 1500 for gold protector.