A. officinalis

Preserving Asparagus

Asparagus freezes well if special care is taken to assure that the young, tender spears are treated properly before freezing. If using the traditional method, make sure that the time spent in the blanching boiling water bath is not too long. Small spears should not be blanched for more than two minutes and larger spears should not be blanched for more than three minutes, tops.

Vacuum sealing the asparagus spears allows you to freeze the spears without the blanching, keeping the texture fresh and the color at optimum green.

Drying asparagus is also a good way to preserve asparagus. This method is great for use in soups and can be taken camping, to use in stews and campfire cooking.

The History of Asparagus

Asparagus was first grown around the Mediterranean Sea and has been used by the Greeks and Romans for both food and medicine for over 2,000 years. Since the 1600's, it has been grown in the United States, and is a popular early Spring treat throughout the world.

Asparagus is rather difficult to grow and requires a little more work to bring to harvest than some of the other vegetables. Most gardeners plant one or two year old root stock, placed into a trench dug 12 to 15 inches deep and 10 to 12 inches wide. The bottom of the trench should be mounded with 8 to 10 inches of mature compost. In order to give the roots the best start, soak them in water overnight and plant them into the trench, spreading out the roots evenly over the mature compost. Cover the roots with two or three inches of soil and water. This allows the roots to be watered thoroughly during their first growing season. As the growing season progresses, GENTLY pile more garden soil over the roots and around the stalks, so that, by the end of the growing season the soil level in the trenches is even with the surrounding garden. Allow the foliage to die back in the Fall and then cut to the ground.

Asparagus does not like to compete with weeds, so a mulch layer should be applied to help keep the weeds at bay.

One year old root stock will produce a crop within two years instead of the three that it will take if you grow the asparagus from seeds. By the third season, you should be harvesting your asparagus crop, and, with any luck the roots will produce asparagus spears for fifteen to twenty years before you will need to replant root stock.

The tender, new spears are usually collected when they are six to eight inches long, way before the bud heads open to reveal the beautiful, feathery foliage. This foliage is a popular "filler" for flower arrangements.

Edible asparagus should not be confused with Asparagus fern (A. plumosus), a delicate house plant that has fine, narrow leaves and looks similar to edible asparagus (A. officinalis).

Culinary Uses of Asparagus

Because Asparagus looses its nutritional value quickly after cutting, it is best to use it within a few days of harvesting the spears.

Asparagus can be steamed, boiled, cooked into sauces and casseroles, and eaten raw. Be careful not to cook too long, as the spears will become limp and loose some of the delicate flavor. Cook only the amount needed for the meal, as cooked asparagus does not keep well at all!

Harvesting Asparagus

Asparagus starts out slowly and should be harvested in limited amounts until the plants are mature. This means that, if you are planting seeds of asparagus, the full harvest will be mature in three years. One Year Old roots can be harvested after two years of growth and Two Year Old roots can be harvested after one year of growth.

During the first harvest season harvest for two weeks, the second harvest season, three weeks and, when the plants are mature after three seasons, the spears can be harvested for four to six weeks.

Harvest spears that are about the thickness of a wooden pencil and about 6 to 8 inches long, cutting just above the soil line.

To produce white asparagus, as the spears start to grow, mound soil over them, gently, to cover 8 inches or so. As the tops of the spears break the surface, remove the soil and harvest the spears just above the original soil level. The soil keeps the spears from using the sun to manufacture chlorophyll, which turns the spears green. Do not try to harvest white asparagus spears until the root stock is at least 4 years old.

Preserving Asparagus

Asparagus is a delicate vegetable that looses nutritional value quickly, so preserving asparagus must be done as soon as possible after harvest.

Asparagus Math:

Asparagus Spears prepared by removing the tough lower stems:

16 to 20 Medium Stalks = 1 Pound = 500 Grams = 3 Cups = 750 mL

Freezing Asparagus

Drying Asparagus:

Asparagus can be dried for long term storage for use in soups and stews, sauces and casseroles. It is a great way to prepare asparagus for use when going camping.


Wash the Asparagus spears and cut the larger stalks either in half or small pieces (1" or so).


Water Blanching: Choose the natural pretreatment of your choice from the chapter on Drying Basics, such as lemon juice, vinegar and salt, or a saline water solution, and dip the Asparagus Spears and or pieces into the boiling water bath for 30 to 40 seconds and remove to cool.

Steam Blanching: Choose the natural pretreatment of your choice and steam blanch the Asparagus for 40 to 60 seconds, then remove and let cool slightly.


Using a Commercial Dehydrator: Usually 6 to 8 hours.

Using your Oven: Usually 3 to 4 hours

Solar Drying: Usually 8 to 10 hours


The Asparagus is thoroughly dry when the spears feel leathery and are brittle to the touch.


Soak the Asparagus in unsalted water for 30 minutes or so to re-constitute the vegetable. The usual proportions for soaking the Asparagus is two (2) cups of water to one (1) cup of dehydrated vegetable and soak until tender.

Home Canning of Asparagus

Because Asparagus has a low acidic content, any home canning of this vegetable will require the use of a pressure cooker. The temperature required to kill off all of the microorganisms that accumulate on the food product needs to be higher than the temperatures achieved by a boiling water bath process.


Wash the Asparagus spears and remove the tough woody portion of the stem. The easiest way to do this is to hold the spear gently with both hands...one at the tough end and the other at the top of the spear. Gently bend the stalk until it snaps. The portion that breaks off will be the toughest portion, which can either be discarded or chopped up to be dried. Save the tender top portions for the canning process.

Two ways to process the produce in jars include:


Pack the washed, trimmed spears tightly into the sterilized, hot jars with the top of the spear pointing up and add 1 teaspoon of canning salt per quart and cover the spears with boiling water, leaving 1/4" head space. Secure the lids and screw bands onto the top of the jar and process in the pressure cooker canner. Process pints for 25 minutes and quarts for 30 minutes


Blanch the Asparagus spears in a boiling water bath for 30 to 40 seconds. Pack the spears as hot as possible into the sterilized, hot jars and add 1 teaspoon of canning salt per quart. Always pack the Asparagus into the jars with the tough bottoms down and the tender spear tips pointed up. Pour the hot canning liquid used to blanch the spears, or, use fresh, hot boiling water into the jars, leaving 1/2" head space and secure the lids and screw bands. Process the pints for 25 minutes and the quarts for 30 minutes in a pressure cooker canner.