Once you have bought your crops, use a hoe to make the ground plantable. Then, go to the menu a select a crop to plant. Once planted, water them twice a day (when the ground looks dry).
When they have grown, pick them off the ground to sell or to duplicate. If you want the grade of one to go up, use fertilizer (bought from Vesta) on them regularly. Also, if you use the Seed Maker, you can duplicate your seeds.
Do not plant crops within 8 squares of a tree otherwise they will die. Trees are bought from Vesta and can be planted at any time of the year. Trees only need watering twice a day for a year then they will mature. They may be planted at any time but they will only produce fruit in the set season after they have fully grown. Here is the way to plant them:
Enter Takakura’s house at around 6.00AM to meet Tartan. Tartan is a two headed plant that can mix to different types of crops to make a whole new type. When you first meet him you will need to talk to him a lot before he offers you the chance to hybrid. When you do get the option, mix two different types of plant and see what comes out. Hybrid plants sell for a bit more g than normal ones. There are a lot of different Hybrids so you will have to experiment.