There are 6 category of plants. Grain, fruit, vegetable, flower, Spice and Cloth.
Each catergory has 3 tier plants except spice.
So you need to research each tech that you want to grow.

Now I explain each plant category.
First is grain. Grain plant is main source of food.
1 tier Grains are Foxtail millet and Sorghum.
2 tier Grains are potato and Barley.
3 tier Grains are wheat, rice and corn.
Using these, you can make grain flour.

Second is fruit. Usally fruit is main source of dessert.
1 tier fruits are grape and peach.
2 tier fruits are orange and olive.
3 tier fruits are apple, strawberry and Melon!.
Using these, you can make dry fruit, fruit pickle and fruit juice.

Third is vegetable. It's usally used to extra ingredient.
1 tier plants are radish and mugwort.
2 tier plants are Cabbage and Lettuce.
3 tier plants are Carrot, Sweetpepper and Pumpkin.
Using these, you can make cutting vegetable.

Fourth is Spice. It is used to make tea and lavish cook.
1 tier spice is Cinnamon.
2 tier spice is chilly pepper.
3 tier spcie is black pepper.
Using these, you can make spice powder.

Five is flower. It produces sweet honey!
1tier is red flower.
2tier is purple flower.
3tier is honey flower.

Sixth is cloth
We have cotton, hemp, flax and silk. also devil.
Silk is special. Other things are just made from fiber.
But silk is made from silkworm farm!!