Ease of Use

• Worm beds can be kept indoors in a warm area that encourages worms to breed and create fertilizer. Compost heaps require a larger area in a garden. You can create a compost heap using a bin with a lid to contain odors and repel rodents, or just as a pile on the ground to encourage worms to enter the heap.
  
  

Turning

• Compost heaps require turning every two to three weeks. Usually a garden fork is used to move the material from the center of the pile to the edges and back. Worm beds require very little attention apart from the regular addition of food waste and the introduction soil, limestone or crushed eggshells every two months to provide grit and moisture.
  
  

Size

• For a worm bed to generate fertilizer, it must have 2 square feet of surface area for each person whose organic food waste is used in the bed. Only 1 square foot of food waste per person can be introduced each week for worms to create fertilizer. A compost heap can be any size and can receive an unlimited amount of food.
  
  

Nitrogen

• Adding green, plant-like material to a compost heap introduces much-needed nitrogen that keeps the heap generating fertilizer. Nitrogen-adding materials include rinds, fruit and vegetable peels, and grass cuttings. Worm beds generate fertilizer as long as the worms have sufficient food, soil and bedding.
  
  

Worms

• When creating a worm bed, you can choose the kind of worms introduced to the bed. Red worms are the most common because they can eat more than their own body weight in waste and reproduce quickly. Dampness in a compost heap encourages worms to enter, but the majority of worms that enter compost heaps do not provide fertilizer as quickly as red worms.
  
  

Construction

• A compost heap requires a layer of brown material followed by a layer of green material followed by a layer of soil. To create a worm bed, you need a bin, a layer of bedding, worms and food for the worms.