This is a 50sqm balcony/terrace on the 2nd (3rd American) floor of a rental apartment building. I immediately knew we had to take the apartment, because having a balcony garden was my number 1 wish. In that sense, we definitely got super lucky.
This is year 4 of the garden, and it feels like we've reached "routine" with it. In the first year, we lugged about 2.5 cubic meters of soil up there to fill all the pots. From June-October, this space is enough to fill 100% of our (two people) vegetable needs.
Unsurprisingly, this is way too much to water by hand every day, not to mention when we're not home for some days/weeks. The balcony is also south-facing, and it gets hot in the summer (seriously, I have burnt my feet on the stones before).
Unfortunately, there's also no water outlet on the terrace itself, and the landlord said "no" to putting one there (which was expected, the way the house/apartment is built is not really suitable for that).
Our solution has been to put two 300l rain tanks on the balcony (atop of load bearing walls). They get filled by a hose from the kitchen tap whenever required. The barrels are connected by a second hose. In the one in the greenhouse, a rain barrel pump sucks water out, into a watering computer and optionally to a hose for manual watering.
From the watering computer, two watering circuits start; originally the plan was to distinguish between plants that constantly needed a bit of water, and ones that preferred a lot of water occasionally (e.g. the citrus plants); in practice, it turned out to be easier to just always water everything a bit. Oh well.
The watering computer itself it pretty dumb / not connected to an app or the like; it just opens the valves every 8 hours for (in the summer) 3 minutes each time. That's mostly OK. On super hot days, I sometimes start a fourth round of watering in the early afternoon.
The pump is however plugged into a Zigbee-enabled smart socket, which is controlled by an automation via HomeAssistant (so, all-locally, thankfully). The main purpose of this is an automation that disables the pump when there has been a lot of rain in the past 24hrs, or a moderate amount of rain in the past 8 hours. Not that important when we are home, but usually extends the number of days we can be away from home by 2-3 days for a full filling of the tanks.
Finally, here's some pictures and a video from the past couple of years. I think this year is the first year where no new pots were added, and we needed to buy hardly any new soil (the compost bin has really been worth it in that regard, as well!)
Happy to answer any questions!!
