These are the steps:
  1. First open PvZ
  2. open Zombotany or Zombotany 2 minigame.
  3. pick the plants ( you can pick anything wihout sun producting plants, dont chose upgrade plant)
  4. return to the main menu
  5. open the userdata folder (Plants VS Zombies userdata)
  6. find a DAT file named game1_16 or game1_32
  7. Rename it into game1_17 or game_33 (before renaming if you notice there is alredy a game1_17 or game1_33 delete it)
  8. open the wall nut bowling
  9. the plants seem to be free, plant them. They even can be planted in one same square.
  10. wait for the zombies coming and plant your wall-nut ,Crush them.

Tested and worked!

If it not work leave a message to my talk Page.

Be Careful the PvZ sometime Eror when you edit a user data game file.