A juicer will extract the juice from fruits and vegetables, separating them from the pulp by crushing, grinding or squeezing the liquid out, leaving behind just the thin juice without any of the fiber. Blenders don't separate your ingredients, instead they blend them together for a thicker consistency. So it's really as simple as it sounds: Add veggies/fruit to your blender with some water and blend together. You need to add the water to get the veggies going. You'll then strain the mixture through some cheesecloth to remove the pulp and then BAM you've got green juice.