Prepare the asparagus spears: Rinse and pat dry. Cut off the woody ends. You may need to cut them down more so that they will fit in the jars.
Prepare the salt brine by mixing 2 TBSP of salt per 4 cups of water. Stir until dissolved.
Assemble the jars: Pour 1/2 TBSP of pickling spice in the bottom of each jar. Place asparagus in jars.
Pour the salt brine into the jars, making sure to submerse the asparagus as much as possible. Leave about 1/2 inch of space at the top of the jar.
Place the seal on and screw the lid on securely. Dont make it too tight or the seal could warp.
Place in a dark, dry cupboard for at least 4 days. DO NOT REFRIGERATE! Your asparagus will begin to bubble slightly and may smell slightly tangy. This is good. After 4 days you can start to taste it. When it reaches the tanginess you like, place the jar(s) in the fridge. The flavor will continue to develop for up to a month.