When your crops are ready to harvest, you can cut them for use in your cooking or other purposes. Some crops should be harvested from the top of the plant, whereas some crops should be harvested from the base of the plant.
How do you determine if your plants should be cut from the top or from the base? If you see stems and pairs of leaves on your plant, you can cut off the topmost pairs of leaves and just be careful to leave enough leaves for the plant to survive each time.
If you see rosettes with new leaves that grow from the middle of the plant, you can cut off the outermost leaves close to the base. For plants that bear fruit such as tomatoes, you can simply cut the fruits off when they have ripened for consumption.