A good substitute for cardamom is a mixture of equal parts of cinnamon and nutmeg. Another option is to use equal parts of cinnamon and ginger or cinnamon and ground cloves.
There are two varieties of cardamom: brown and green. The most commonly used variety in Indian and Middle Eastern cuisine is green cardamom, and recipes that use cardamom usually require the green variety. It can be substituted with brown cardamom, which is known as black cardamom, as well.
Ground cardamom can be used as a substitute in a recipe that calls for whole cardamom. Six pods of cardamom can be used in place of 1 teaspoon of ground cardamom, and 18 seeds is equal to six pods of cardamom.