How Can You Tell The Difference Between Worm Castings and Soil?

Can't really tell if I'm getting soil or worm castings, they both look the same.

Earthworm castings are generally dark and crumbly, resembling coffee grounds. But what do you mean you're not sure what you're getting... where are you getting it from?

Soil is a mixture of clay, silt, sand and humus (thoroughly decayed organic matter). Earthworm castings are basically a form of humus (as is compost). If you take a sample of soil, add water, shake it up and let it sit for a while it will separate visibly into its constituents: sand, silt, clay\humus. They are all of different particle sizes, sand being the largest on the scale and clay\humus the smallest. The sand should sink to the bottom.

Here are more in-depth instructions on how to do this: http://www.ext.colostate.edu/mg/gardennotes/214.html

taste it! if it taste like shit its dirt...if it tastes like soil its worm crap

Buy direct and you wont have a problem wiggly worm makes great castings and black gold makes great soil.