At one time, canned food items were packaged in tin cans. Today, although the term "tin can" remains, most food cans are actually aluminum. Regardless of metal used, plants can be grown in cans but a few caveats exist.
The tin can holds soil for the plant. The rigid walls and rather small size of cans used for food containers can limit what size plant grows in it. Plants must be removed and transplanted from a tin can before the roots become cramped or encircle the base, making the plant difficult to remove.
An important modification is needed before a can is filled with soil and a plant added. At least one drainage hole in the can's bottom ensures water evacuates the soil and plant roots do not suffocate or rot.
Metal cans conduct heat and cold well and don't provide much insulation to the soil or plant roots. Metal placed in sun heats up quickly, and that heat is transferred to the soil and causes soil and roots to dry out more quickly. Conversely, freezing temperatures chill the metal and cause the soil to chill or freeze more quickly as compared to a wood or thick polyurethane container.
If the container is truly made of tin, traces of this toxic element may be absorbed by plant roots. Avoid planting edible plants such as vegetables in tin cans.