Take a look in your kitchen trash. Coffee grounds, onion skins, the ends of carrots, that bag of spinach that went slimy. According to the EPA, food scraps and yard waste together make up more than 30% of what Americans throw away.
Most of that could be feeding your plants instead.
Compost is about the best organic plant food there is, and it’s free. The good news is you don’t need a backyard or a big wooden bin to make it. Plenty of people compost in studio apartments. It mostly comes down to choosing the right method for your space.
Why compost matters for container plants
Potting mix doesn’t stay rich forever. Every time you water, a bit of nutrition washes out of the bottom of the pot. After a few months, your herbs are basically growing in an empty sponge.
Compost puts that life back. It feeds plants slowly and gently, helps soil hold water without getting soggy, and brings in helpful microbes. For an organic grower, it replaces most bottled fertilizer.
Pick the method that fits your space
There’s no single right way. Here are the four options that actually work in small spaces:
| Method | Best for | Space | Takes meat and dairy? |
|---|---|---|---|
| Collect and drop off | Zero effort, zero mess | A countertop bin | Depends on the program |
| Worm bin | Apartments, steady plant food | Under a sink or in a closet | No |
| Bokashi bucket | Small kitchens, all food scraps | A 5-gallon bucket | Yes |
| Small outdoor bin or tumbler | Balconies and patios | A corner outside | No |
Collect and drop off. Keep a lidded container on the counter (or in the freezer, which stops smells completely) and take it to a city drop-off point, a community garden, or a farmers market. Search your city name plus “food scrap drop off”. You don’t make compost yourself, but many programs will let you take some finished compost home.
Worm bin (vermicomposting). Red wiggler worms eat your scraps and turn them into worm castings, one of the best plant foods you can get. It sounds odd, but a healthy worm bin doesn’t smell, and the worms stay put. This is our favorite option for apartments, so we walk through it step by step below.
Bokashi. A sealed bucket where you layer scraps with a special bran that ferments them. It handles meat, dairy and cooked food, which worm bins can’t. The catch is that the result isn’t finished compost yet. You bury it in a pot of soil or a planter for a few weeks to finish breaking down.
Small outdoor bin or tumbler. If you have a balcony or patio, a small tumbler works like a regular compost pile. Turn it every few days and it breaks down faster.
A quick word on countertop electric “composters”: they dry and grind your scraps into a crumbly material. It’s handy for cutting down trash, but it isn’t true compost, so mix it into soil and let it sit a few weeks before feeding plants with it.
What goes in: greens and browns
Every compost system needs two kinds of material:
- Greens (wet, rich in nitrogen): fruit and vegetable scraps, coffee grounds, tea leaves, fresh plant trimmings.
- Browns (dry, rich in carbon): shredded cardboard, paper egg cartons, plain newspaper, dry leaves.
A good rule for bins is roughly two to three handfuls of browns for every handful of greens. Most smells and fly problems come from too many greens and not enough browns.
Leave out meat, fish, dairy, oily or greasy food, pet waste, and glossy or shiny paper. (Bokashi is the exception for food.) In small indoor systems, go easy on citrus peels and onions too, since worms don’t love them.
How to start a worm bin, step by step
- Get two stackable plastic tubs about 10 to 14 gallons each. Drill a few small holes in the bottom of one tub and some air holes near its top. The second tub goes underneath to catch any liquid.
- Add bedding. Fill the top tub about halfway with shredded cardboard or newspaper, dampened until it feels like a wrung-out sponge. Toss in a handful of potting soil.
- Add worms. You want red wigglers (Eisenia fetida), not garden earthworms. About a pound is a good start. You can find them online or at many garden centers and bait shops.
- Feed small amounts. Start with a cup or two of chopped scraps a week. Bury the food under the bedding instead of leaving it on top. Chopped scraps break down much faster.
- Keep it damp and dark. Store the bin somewhere between about 55 and 77°F (13 and 25°C), like under the sink or in a closet.
- Harvest. After three to six months, the bottom will be dark and crumbly. Push everything to one side, add fresh bedding and food to the other side, and the worms will move over in a couple of weeks. Then scoop out the finished castings.
Fixing common problems
- It smells bad: too wet or too much food. Add dry shredded cardboard and skip feeding for a week.
- Fruit flies: bury food deeper and lay a sheet of damp newspaper or cardboard over the top. Freezing scraps before adding them also helps.
- Worms trying to escape: the bin is too wet or too acidic. Add browns and cut back on citrus.
- Nothing is breaking down: the bin is too dry or the pieces are too big. Mist it and chop scraps smaller.
How to use compost in your pots
- When planting: mix about one part compost into three or four parts potting mix.
- As a top-up: every couple of months, spread a thin layer, about half an inch (1 cm), on top of the soil of your herbs and vegetables.
- As a quick liquid feed: soak a handful of compost or worm castings in water overnight, then use the water on your plants. Pale, yellowing leaves are often a sign of a hungry plant. Here’s how to tell why leaves are turning yellow.
Start with one bin
You don’t have to change everything at once. Put a container on your counter this week and start saving scraps. Whether you drop them off or feed them to worms, you’ll throw away less and have better food for your plants.
Just getting started with plants too? Take a look at what to plant this month.
Want your plants to thrive once you’ve got great soil? UrbanLeaf gives you one simple organic care task a day for your plant, including when to feed and when to water, so nothing goes to waste. 🌱