Before starting, check with building management for legality, safety, and especially weight considerations. Lightweight alternatives to traditional materials, such as potting mix and growing containers will likely be necessary. Learn more about the weight of wet soil so get some idea about how much weight will be added to the balcony.
It is always best practice to get permission from your landlord, to avoid damage which you might have to pay for, or a mid-growing season take-down of your set up when they find out the potential implications of your garden.
The main concerns from homeowners with balcony gardening are to do with weight and water. Containers heavy with soil, water, plants and other items may weigh too much for the structural supports of the building. Once you learn more about the solidity of the structure, you can plan your garden accordingly. With a strong concrete balcony you can grow heavy root vegetables and have many containers and growing/water collecting systems. With a more flimsy balcony, you may have to grow things like herbs, lettuces and lighter produce. If your landlord says “no garden!” express how you can work together to compromise with a smaller project. They may even work with you to get a water collection barrel or compost bin going!