On your balcony, a bucket of water that you throw kitchen scraps in and make liquid compost

Looks like people do it with weeds as well

https://youtu.be/4Wo8XfCIvu8

Another thing is bokashi that involves fermenting kitchen scraps and you can make liquid fertilizer from that too

Another thing I just thought of is a worm farm.

This will depend on climate and space however, so do your research.

Some red wrigglers in an old bin with kitchen scraps will go a long way.

With 2 boxes you can harvest the worm compost easier and with a tap (you can install yourself) on the bottom to durian and extra juice would be ideal

The grass clippings are a good idea and easy - find something porous to hold them in (cheese cloth? a hairnet would work) and a large bucket of water. soak for a week(?) like making tea and you’ll have a great nutrient plant water.

If you have any banana peels grind em throw some in the bucket, they have great phosphates and potassium. Probably keep the bucket covered in case mosquitoes. Dispose of the solid matter as appropriate, you don’t want algae or mold so make it use it clean it cycles.

20:1 diluted urine is my first idea, but I’ve never tested it on house plants (because the salt accumulates and the water does not run off it may be riskier). But it works great for garden plants, tomatoes, cucumbers.

PS: I guss you can shower the plants until water runs if you suspect salt accumulation…

Coffee grounds and eggshells will go a long way, but they aren’t a substitute for any other augmentation.

I wouldn’t even consider composting in an apartment - the logistics are just too painful in such a small space (and with long composting timelines).

So about the watering - the cheapest thing you could do is get a faucet aerator-to-hose adapter. It screws into the aerator on your sink and lets you screw on any regular garden hose fitting. The down side is that many faucets don’t like seeing back pressure when the faucet is on, so you could damage your faucet if you turn a valve off at the end of the hose. One option is just “don’t turn it off”, or look at a waterbed filling/draining kit. It’s got a sink adapter very similar to the metal one but it lets some water hiss through under pressure.

Another possible fertilizer source would be an all purpose chemical fertilizer from a dollar store. You don’t get much but you also don’t need much. Definitely not as natural as rolling your own compost, but a lot more practical in a small space.

Mixing in uncomposted material will actually reduce nutrient availability to your plants so I wouldn’t recommend it. I also strongly recommend against indoor composting.

Alternative get a large watering can and carry that, many times, but fewer times. A family member had a huge balcony garden and never ended up with a tap.

If your starting soil is decent, and you don’t over plant, your need for fertilizer is not that high.

Some municipalities will have programs where you can get free or low cost compost; I’d ask around there, as well as look for local gardening clubs and mutual aid groups to see if anyone has some to spare.

Also, both rabbit and Guinea pig droppings can be pretty good soil additions, if you know anyone who keeps either as companions/fosters or a rescue organization for either.

Also also, if you have any friends who keep fish, the water left over from when they change the water out in their tanks is also nutrient rich

Spent mushroom grow media should help with adding nutrients to your dirt (With a nice mushroom bonus).

You can look into farming some oyster mushrooms and then after the second flush add that to your soil.

You might need to have a decent size mushroom operation if it is your main source for nutrients however.

I think a sneaky micro worm farm is the primo solution personally. Landlord be damned.

Maybe just use cheap synthetic fertiliser if you want?
It’s used for potted plants, so there’s basically no runoff.

I personally love Masterblend, which is what plants crave ® /s (contains all essential nutrients and you don’t need much of it). You need to weight and dissolve it tho, but that’s not much extra effort for me.

But any cheap all purpose fertilizer with micronutrients will do.

Maybe bokashi. If you dont make too much at a time you can do the soil part indoors without smell. And the fermentation is closed lid

the most i use for container gardening is the same tomato feed for every plant, tbh. you might be able to find a bottle within your budget, and since it’ll need to be diluted a lot, it should last a while.

if you want to really go above & beyond, plant-scraps-tea & crushed eggshells etc will top up their nutrients. if you’re ever boiling veggies etc in unsalted water, consider letting it cool down & watering your plants with that too.

overall, i try not to go overboard with feeding various nutrients, unless it looks like the plant needs a pick-me-up. it’s a lot easier to give them more nutrients when they’re too low, than to try to flush out nutrients if they’re getting too much of something.

Have you tried bokashi? If anyone asks, you just say the container is your trash bin

I mean… for the truly free solution you could potentially use your own urine. It’s a little much for most people but historically it was used.