Some advice to fellow garden lovers whose outdoor space is similarly contained to a few square feet of concrete way up in the air:
Keep a small compost bucket on the balcony. This serves a dual purpose- collects food scraps from the kitchen (while preventing the inside from smelling like death and decay and attracting flies), and also collecting your plant trimmings/dead flowers/etc. Then just empty it once a week or whenever it’s full (my building has a compost bin alongside the garbage/recycling). Or if you don’t care about the environment just wrap all your scraps in plastic, light them on fire and throw them into your nearest drinking reservoir. (those are the only options).
Water at anti-social times. For example, do not water all your pots on a sunny weekend evening when the neighbours below you might also be out enjoying their balcony. Cause they might not appreciate that dirty stream of water flowing down onto their barbecue (hypothetical situation…). So just try and stalk their movements enough so you can figure out their work schedules, and water around that.
Skip the watering can. Unless you live in a fancy foreign-investor penthouse or have an extra bedroom dedicated to your gardening tools, it is an unnecessary waste of space when you’ve only got a few plants. I’ve been using a big old glass bottle that was lying around, that also gets used as a vase sometimes.
Pay more attention to those little sun/shade symbols at the nursery. Being up in the air seems to magnify the sunlight (science alert), so it’s harder to get away with mixing plant types. Because of the direction we face and lack of any nearby ten-story leafy trees providing shady relief, my plants get direct sun all morning and afternoon. If I know it’s going to be particularly hot I will sometimes move the more delicate plants (like my basil) just inside the door in the shade for the day.
Consider your view. As we are lucky enough to look out onto the water (and city if you look left and mountains if you look right), I didn’t want to grow anything too high that might block it (I’ve stuck to herbs, flowers and strawberries). However if you look onto a rat infested back alley or directly into the nudist seniors societies Zumba practice room, may I suggest some tomatoes or peas (or binoculars, should you be so inclined).
That’s all for now. Google will tell you all the other practical/boring info you might need to know (“Check your buildings rules!” “Get creative with your space!”). And remember, while you may covet the three acre mini farmland of your (fictional) neighbours, just appreciate your lack of bugs, weeds, and medical bills for your aching bendy back.