Select freshly-harvested asparagus. Ideally, freeze your stock when the seasonal demand of the asparagus nears its peak, i.e. from early to mid-spring.

Wash each spear with cold water to remove any dirt or impurities. Keep washing thoroughly until it becomes entirely clean.

Trim the woody ends of your spears. The bottom end of the asparagus hardens with time. Therefore, you have to slice off the bottom third of your spears. 

Next, snap the spears into two. If not, cut with a sharp paring knife. Repeat this step for all the spears. 

Chop the asparagus into pieces that are about two inches in length. Althoughyou can freeze the whole spears, cutting it is necessary for the next process: blanching.

Use a pot that is big enough to hold the asparagus pieces. Fill two-thirds of the pot with water. Bring the water to a boil.

Pour water and ice cubes in another large bowl.

After boiling the water for three minutes, drop your asparagus spears or pieces into the water. Set a timer for three minutes to cook the asparagus.

Immerse all the boiled asparagus into the icy bowl immediately after taking it out of the pot. Set another timer for three minutes. 

Use a dry towel and dry off the damp asparagus. If you are careless during drying, then your asparagus will be frosty in the freezer and could become freezer burnt.

Lay down a baking sheet and distribute your asparagus pieces evenly. Use a plastic wrap as a covering for the sheet.

Add the baking sheet to your freezer so it can be flash-frozen in an hour.

Use plastic bags that are considered reliable for extended use (around a year). Stick labels with dates on your containers so that you can determine the condition of your asparagus.

Make sure that you pack asparagus tightly, eliminating any air from the container. To do this, you can apply vacuum packaging. 

Lastly, freeze the asparagus for a year or longer.