Wall-nut First Aid

Wall-nut First Aid is an item that can be purchased from Crazy Dave's Twiddydinkies for $2000 after the player has beaten Adventure Mode at least once.

Overview
Wall-nut First Aid allows the player to plant new Wall-nuts, Tall-nuts and Pumpkins on top of damaged plants of the same kind without having to dig them up first. This allows the player to replace a defensive plant when a Zombie is chewing on it without digging it up and giving the Zombie a chance to escape. Wall-nut First Aid does not work on other plants, including Garlic.

Tall-nuts still cannot replace Wall-nuts without first digging up the Wall-nut, so keep this in mind if your strategy is to start off with cheaper Wall-nuts before replacing them with stronger Tall-nuts. Planting a Pumpkin around the Wall-nut before digging it up would keep the space protected during the swap, but this would be a waste of Sun, so it would make more sense to wait until there are no zombies nearby.

Sunny Days Achievement
For the achievement Sunny Days, it is wise to have Wall-nut First Aid purchased, so you can easily replace the Wall-nuts or Tall-nuts the zombies are chewing on, while collecting Sun as you can.

Trivia

 * Store_FirstAidWallnutIcon.png can't plant a new Wall-nut, Tall-nut or Pumpkin over an undamaged one. They're undamaged until they lose at least one-third of their health after getting 24, 48, and 24 bites, respectively.
 * Even though the Garlic is a Defensive Plant, the Wall-nut First Aid does not work on it.
 * There is a bug with first aid while linking on the DS version. (Citation needed).