Keys are items in the Chinese version of Plants vs. Zombies 2: It's About Time but they are also present in Plants vs. Zombies Online. The player needed them to open gates to get boosts and plants, and to unlock Brain Busters. There are different variations of keys for each world, however in Plants vs. Zombies Online they are all the same.
Keys were removed from Plants vs. Zombies 2: It's About Time in the 1.7 update as a new method of unlocking plants and rewards replaced the original layout. Any keys the player had before the update were turned into coins.
Keys are found as a rare drop off of all zombies killed in a time zone. The odds of a zombie dropping a key are relatively low, around one percent off of any zombie, regardless of health or speed. Keys could also be found off of the Treasure Yeti every once in a while, and a lunchbox can carry three keys of the area the Yeti was killed in. Finally, Piñata Party piñatas had a chance to carry one key for any area, as long as they player had that area unlocked.
- Killing the Treasure Yeti was one of the best ways to get keys, as every other lunchbox has three keys.
- Playing levels with a high zombie density provided more chances for keys to drop.
- Completing Pinata Parties could have resulted in a few keys being rewarded.
- Zombie strength does not effect drop chances, so it was more practical to battle large amounts of weaker zombies for key farming.
- Completing Adventure Levels
- Each gate involved 3 to 5 keys to be unlocked, except for the Special Delivery gate in Ancient Egypt, which involved 1.
- As of update 1.7, the player's previous Keys (if any) have been turned into coins, because there is no need for them anymore.
- Keys max out at 99; any more collected will not increase the counter past the maximum.