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.

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.

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

$30 is "you need to steal it" territory. Buy a shovel and a bag from a thrift store. Dig up soil near office buildings, ideally mega corps that are assholes.

You can get mulch from the same place. Some munipalities will also drop off free mulch from the tree cleanup they do around power lines. Check your local area to see if they have a program.

You can use this for fertilizer:

https://www.costco.com/p/-/miracle-gro-shake-n-feed-all-purpose-plant-food-8-lb/100411468

Its all purpose and will last years in a balcony garden. Its not tuned to each plants needs, but I can vouch for it working across hundreds of different plants without issue. Shake out the pellets every 3 months of the growing seasons and that's that.

For water, do rain catchment if possible with any old container you have. A large cistern is best, but any container you can seal will do.

Composting is basically not realistic inside. Its rotting food/soil on purpose over sustained periods. Lots of bugs, can be very smelly. Don't recommend.

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.

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.

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

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

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.

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...

If you have local free groups (Freecycle, Buy Nothing, Everything is Free) this isn't even that weird an item for an In Search Of post. Someone in town will have something they'll be happy to share.

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

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.

Everyone likes to claim that eggshells are some kind of a amazing fertilizer, but they aren't. They are calcium carbonate, which is not really water soluble (in other words, not available to plants). You can improve solubility by baking and then pulverizing them to a powder. They are basic, though, so it's possible to rise the pH too much for some plants. I wouldn't just do it willy-nilly.

It would be awesome if balcony gardeners could just scrounge all the fertilizer their plants need, but it's not easy. If you are on a budget, you can just buy a canister of miracle grow that will last indefinitely for $12.

Our city will compost mountains of compost then every May they will give them out 5 bucket per car and it's great as planter soil or just to top off the yard. If you keep checking Kijiji or Facebook some people will give out top soil or extra planter soil for free to get rid of it from renovation or too much order. You can try those.

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.

You don't really need fertiliser. Plants fixate nutrients in the soil by feeding bacteria from the roots who then break organic matter down. Fertiliser is just a shortcut.

You also don't need a hose pipe for a balcony garden.

I'd focus your budget on some decent soil for which there's no real alternative. The dirt around office blocks will be crap. The top soil from the woods will be mostly leaf mold which dries out really quickly.

If you can find some olds pallets (make sure they're heat treated by checking for an HT stamp) you can build a raised bed. You can fill the bottom of that with compostables and put the soil on top. The composting process generates heat which can help extend the growing season. Once you've harvested you can turn the earth before loading it up for the next year. It's a lot of work but it fits your requirements.

If you know another gardener they'll probably have spare pots and seeds to give away. If you have enough left in your budget you might invest in seedlings (little plants) - a headstart will improve your chances of actually harvesting some veg this year if you're just starting out.

Some have mentionned pee, which is good but unfortunately provides only nitrogen.

Well, I have another good source of nitrogen to suggest: legumes. Grow legumes and they will naturally add nitrogen to your soil, without adding any sodium

I just stumbled across this video on DIY compost-free fertilizer today and immediately thought of this post, so I'm sharing it here. https://m.youtube.com/watch?v=s1q7NonSlEU

Quick summary if you would rather not watch: bloom yeast in warm water with sugar, add in what you have of powdered eggshells, wood ash, and Epsom salt. Ratio from the comments that I can't double-check against the video is:

Metric:

• Mix 1 Tbsp of dry yeast into 950 ml of warm water with 2 Tbsp of sugar. Let bloom for 10 minutes, then place into fridge overnight.
• Mix yeast mixture into 19 litres of room temperature water.
• Add 1 Tbsp of wood ash, if you have it
• Add 1 Tbsp of ground eggshells, if you have that.
• Add 1/2 tsp Epsom salt, if you have that.
• Add about 236 milliliters at the base of plant you're fertilizing every two weeks.

'Merican:

• Mix 1 Tbsp of dry yeast into 1 quart of warm water with 2 Tbsp of sugar. Let bloom for 10 minutes, then place into fridge overnight.
• Mix yeast mixture into 5 gals of room temperature water.
• Add 1 Tbsp of wood ash, if you have it
• Add 1 Tbsp of ground eggshells, if you have that.
• Add 1/2 tsp Epsom salt, if you have that.
• Add about 1 cup at the base of plant you're fertilizing every two weeks.

Anecdotal evidence supports this. I cannot find any studies or articles about this because when I try to Duck around and find out, I cannot tell which of the top results are AI slop and it's all over the place. We are in Hell. So my advice is to try it, maybe omitting different ingredients for comparison, and test it out. I'm currently trying to find a good vegan alternative to add calcium in place of eggshells that's cheap, available and which I would actually have on hand regularly as someone who does not use eggs.

Maybe try a lombricompost, it's several buckets with holes between them, with compost worms in (some local community could provide it for free if asked nicely), just put fruit and veggies peeling in with paper or cardboard (60% green matter like cardboard for 40% peelings, like compost) and you will have very good fertilizer, good compost and no trip to bin anymore.

You can build it with old packaging, or buy it used.

I have one in my kitchen, no odors, only a little fruit flies when I'm not paying attention.

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