If you want to turn your old fruits and vegetables into compost but your space is limited, then build a wormery. All you need is an old aquarium or wooden, plastic or glass box. You can collect worms from outside or buy some from a feed store. Then just follow these steps to build a wormery and make compost.
Get an old aquarium or wooden box with a lid. Fill it with a shredded newspaper and moss mixture.
Wet the mixture with water so it is saturated like a sponge. You don't want the worms to swim, though, so don't overdo it.
Add fruits and vegetables that are leftover from your meals. You can provide the worms with extra calcium if you add broken eggshells. Crush the eggshells to powder and mix them in well with the fruits and vegetables.
Top off the fruits and vegetables with another layer of the newspaper and moss mixture. Add the worms.
Wait three months for the worms to turn the food into compost in the wormery. When it's ready, shine a bright light in the wormery so that the worms move to the bottom of the aquarium. You can now harvest the compost.
Use the compost to pot your plants. You can also throw the compost in your garden to enrich your flowers or vegetable plants.
If you use a wooden box to build your wormery verify that the wood isn't treated. Treated wood can kill your worms.