This one isn't for balconies, but it is for apartments, so I hope it makes sense that I am posting this here.

With window hydroponics, you take:

• used water bottles
• a pump kit (with tubing and joints)
• a bucket of water
• growing substrate
• a hanging anchor kit
• silicone steel tube
• chain (for hanging)
• tools (electric drill, plier, hole punch)

... and convert them into a tiny food garden that hangs by your window.
This gives food options for those who live in apartment’s that might not have had the choice before.

You'll of course need plants that do not get too big (such as dwarf tomato plants instead of full-sized). If your window does not get enough sunlight, you may also have to supplement that with grow lights and a plug timer.

You do not need to buy an expensive kit. There are DIY sources everywhere, including this video explaining to use a pool noodle to create a growing substrate(an option to save an old pool noodle from the trash) instead of rockwool or pebbles.

I have not tried this myself, but thought I would share it in case it helps someone.

More Info:

• https://youtu.be/igWJ_8uq_y4
• https://www.instructables.com/DIY-Vertical-Window-Garden/