Wormeries with a large surface area perform better than deeper bin-type wormeries. This is because a larger surface area, means more air so food composts down quicker helping your worms feed and breed faster. Deep dustbins style bins are hard to use, particularly for beginners as they are difficult to empty and because of the reduced airflow tend to become smelly. Stacking wormeries must have the bins which can slide down inside each other so the mesh base must stay in contact with the food below at all times. This is because as the food composts down, it looses volume, and a gap appears above the food and worms cannot jump into the next layer. After having looked carefully at a number of wormeries we have selected the Wormcity Executive wormery range as in our opinion they best take account of these performance factors and also represent excellent value for money and superior build quality