Dietitian's tip: To ensure food safety, be sure to sterilize the jars and lids by simmering them in water for 5 minutes and then letting them cool to room temperature. Then fill with asparagus mixture.
Trim off the woody ends of the asparagus and cut spears into lengths that will fit into the jars. Place spears in colander, wash well and drain. Trim onions. Combine all ingredients in air tight containers. Refrigerate up to 4 weeks.