Mastery Sign

When a farmer reaches level 3 Crop Mastery for a certain crop, they will receive a Crop Mastery Sign. The sign depicts the crop that they have mastered and can be placed on their farm. The sign reads, "PREMIUM [crop name] (+XP) grown here!".

Once a farmer achieves Level 3 mastery of a crop, there is a chance that any crop of that type planted in the future will become a “Premium” Crop. Initial reports show that the amount of premium crops is anywhere from 15 to 50%.

A premium crop looks bigger (like a fertilized crop) and provides more experience. depending on the crop type: Acorn Squash, Aloe Vera, Asparagus, Black Berries, Blueberries, Carrots, Coffee, Cranberries, Ghost Chili, Green Tea, Onion, Pattypan Squash, Pumpkin, Raspberries, Rice, Sugar Cane, Strawberries, Tomatoes. Grapes, Peas, Peppers, Soybeans, Sunflowers. Bell Peppers, Broccoli, Cabbage, Eggplant, Pineapples, Squash. Corn, Cotton, Daffodils, Lavender, Lilies, Pink Roses, Potatoes, Red Tulips, Red Wheat, Wheat. Artichokes, Watermelon, Yellow Melon.
 * 1 XP harvest :
 * 2 XP harvest :
 * 4 XP harvest :
 * 6 XP harvest :
 * 8 XP harvest :

The requirements to obtain a crop mastery sign depends on the amount of crops you need to harvest.

Check this Crop Mastery Level Requirement for more information.