Secret Pinatas
Unlock the game's secret piñatas in one of two ways: feed a piñata specific items or tap a pinata's egg with your Nintendo DS stylus. Feed a gooseberry to a Quackberry piñata to unlock a Juicygoose. Feed a Horstachio a blackberry to unlock a Zumbug. For a Salamango, feed a chili to a Newtgat. Tap a Syrupent egg repeatedly with the stylus to unlock a Twingersnap.
Birthday Trick
Set the date on the Nintendo DS to match your birthday. Play the game and you will be given a birthday cake. You won't be eating it though; smash it up using the shovel and pick up what fell out: Happy Candy, Romance Candy and an egg.
Rare Item Stall
Speak to Ivor Beggar, and when he asks you for money, offer him 1,000 chocolate coins. Supply him with a carrot, bread, corn and Moozipan when he asks for food and drink. His final request is for a jack-o'-lantern and wool; provide a pumpkin and Goobaa. Thanks to your generosity, the beggar will set up a rare item stall in Costalot's store, selling items like One-Pour Wonder.
Other Cheats
If you build at night time instead of through the day, Willy Builder will drop off to sleep halfway through his work. This isn't a bad thing, though -- if you catch him in the act you can poke him with the stylus and he will work faster than before.
Put your taffy on a lit Firebrand and water it straight away to change it into a Reddhott. Taffys are only worth 600 coins and Reddhotts cost 2,100 coins, so this secret is worth doing for the financial benefit alone.
Complete the entire game and finish every task so your completion total stands at 100 percent. You will now have a new title screen.