The Homeowners Column

The Homeowners Column

Growing Asparagus - durable, easy to grow and even pretty

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator
slmason@illinois.edu

What vegetable grows wild along railroad tracks in Illinois? Except for the occasional "wild" tomato plant in my compost pile, asparagus is one of the few traditional vegetables found in the wild.

Once established asparagus is a hardy, durable perennial. A well-prepared garden patch will last 20 to 30 years. Well worth waiting three years for the first harvest. All it needs is a sunny spot with well-drained soil. As an attractive perennial the ferny foliage turns from green to a golden yellow in fall. Plant mums in front of your asparagus patch and you have a beautiful late season flower bed.

Asparagus should be planted as soon as the soil can be properly prepared in the spring. Even with our unusually warm spring, asparagus can still be planted now. Generally asparagus is started from one-year-old crowns or plants and not seeds. The crowns resemble an octopus with their crown of buds and pencil sized roots radiating from the crown. Asparagus can be started from seed, but who wants to wait an extra year for production.

Asparagus plants are naturally male or female plants. They can be purchased as female plants, male plants or predominately male plants. Male plants can be 3-5 times more productive than females. Males also do not produce potentially weedy seeds.

With asparagus varieties the "Jersey Boys" have superseded the "Washingtonians". Older asparagus varieties (Mary Washington, Martha Washington, and Waltham Washington) are ok, but don't yield as well as the male hybrids of 'Jersey Giant', 'Jersey Supreme', 'Jersey Knight' and 'Jersey King'.

I planted a variety called 'Purple Passion' that proved to be pretty and sweet tasting. White asparagus is not a particular variety but a special production technique that eliminates light as the spears emerge.

To plant asparagus, place crowns in a trench 12 to 18 inches wide and 6 inches deep. Crowns should be spaced 9 to 12 inches apart in the trench. Spread the roots outward with the buds of the crown facing up. Cover the crown with 2 inches of soil. As the stems lengthen through the season, fill the remaining portion of the trench with soil. This planting process gets the crown deeper into the soil without forcing the plant to push through 6 inches of soil all at once.

Asparagus should be fertilized in the spring for new plantings (first 3 years) and right after the last harvest in June or July for older plantings. Apply 10-10-10 or similar fertilizer at the rate of 2 to 2.5 pounds per 100 square feet.

Asparagus is one of the earliest vegetables to harvest in spring. It can be harvested the third year after planting crowns, but harvest for only a month then let the ferny stems grow. After the third year the spears can be harvested through May or June. To harvest, grasp 5 to 8 inch long spears at the base and bend them toward the ground. The spear will snap where it is free of fiber. Spears may also be cut with a knife, but make sure not to damage any of the emerging spears. Quality deteriorates rapidly after harvesting so any asparagus that is not eaten immediately should be processed or refrigerated.

Weeds and especially grasses can be a problem in asparagus bed. In early spring do a shallow hoe cultivation so as not to damage the emerging spears but to remove weed seedlings. Apply compost mulch after harvest.

An old gardener's tale is to apply rock salt to the asparagus patch to keep grass seedlings from germinating. It may work, but it is not a healthy practice for the growth of the asparagus. A sure case of dying from the cure. If you want to use salt on your asparagus, wait until it is on your dinner plate.

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