Make sure you have the ingredients needed to make a Perfect Garden charm, and make sure you have at least five to ten Elderberry and Grape Sprigs. Go to "Build Mode" then "Plants" and find the plant called "As The Plot Thickens". Buy ten to twenty of them, and in half of them plant Grapes, and in the other half plant Elderberries. Make a "Perfect Garden" charm, then cast Perfect Garden. This will make your grapes and berries grow to full size, and you can harvest them. After the harvest, cast Perfect Garden again to harvest them again. Repeat casting and harvesting until the charm runs out. To keep getting grapes and berries, just make another Perfect Garden charm. This saves plenty more time and money in tending to the plants and/or running to Magic Town lots to buy grapes and berries.