Enlightened

Difficulty: Very Hard

Enlightened is an achievement unlockable on iOS and PlayStation Vita versions of Plants vs. Zombies. In order to unlock it the player must obtain every Zen Garden plant. Although it takes a long time, it requires little talent, as the player can just buy Golden Mystery Sprouts for a while.

Strategy
This achievement is hard and very luck-based, as you need to collect all 39 plants in the Zen Garden (excluding the Flower Pot, Imitater, and Upgrade Plants), Zen Garden plants dropped by Zombies are rare. Try to repeat Adventure Mode as much as you can.

Another way to get the achievement is to buy Marigolds from Crazy Dave's shop and use the Zen Garden Editor until you have all the plants.

All the plants need to be in your Zen Garden at the same time to unlock this achievement.

You can also use a user file editor to make your Zen Garden complete.

Tips

 * Play levels with a high zombie density so that more presents can be dropped. For levels that commonly spawn plants, you can see Zen Garden.
 * Keep ten chocolates, so that zombies can't drop chocolate.
 * Playing Survival: Endless, I, Zombie Endless and Dr. Zomboss's Revenge will drop every kind of present you need for this achievement.
 * Every ten levels of Vasebreaker Endless and every three levels of I, Zombie Endless will drop a money bag, chocolate, or present. Having 10x chocolate will also lessen the chance of chocolate dropping from these.
 * In the iOS versions, you can try to get as many coins as you can, then buy all the bonus coins in the "Get more coins" section. Make sure to to have at least three GameCenter accounts, then restore all the bonus coins and buy them again. You may then have enough coins to buy a lot of Gold Mystery Sprouts, and you can get this achievement easily.
 * Turn on Cheat Engine for Unlimited Sun and 10.0 or higher Speedhack and overwhelm the plants in I, Zombie Endless for presents up to every 3 levels. This is called present farming.
 * To find out more ways to get Zen Garden plants, see Present.

Trivia

 * The fact that the achievement is called "Enlightened" implies that once one has collected all of the plants for the Zen Garden, they will have achieved a form of Zen enlightenment (considered the ultimate goal in Zen teachings).
 * In the iOS Game Center, this is the achievement that gives you the most points (40).