Long-lived asparagus plants can last decades

Growing asparagus requires patience — from planting to harvest takes two to three years, but the wait is well worth the reward.

Homegrown asparagus is one of the earliest vegetables of the spring. Its quality is much better than store-bought spears, and it is less expensive. Once established, it is easy to grow and in a well-prepared garden patch can last for decades. And asparagus is beautiful. A member of the lily family, its fern-like foliage turns from green to gold in fall, and can be a backdrop to chrysanthemums or other late season flowers.

Barb Fick, horticulturist with the Oregon State University Extension Service, said preparing an asparagus bed properly may reward you for years.

“Asparagus is a hardy perennial and should be planted as soon as the soil can be properly prepared in the spring,” Frick said. “Usually asparagus is started from one-year-old plants, rather than from seed. The plant you purchase will look like an octopus, with long fleshy roots extending from the center crown.”

Carefully choose a site to plant asparagus; a good bed of asparagus can remain prolific for many years. It’s important to dig deeply to remove weeds and amend the soil with plenty of organic matter. Asparagus will not grow well in heavy, poorly drained soils.

Itching to plant? Know when best time to plant what is

Asparagus should be planted in sunny, well-drained sites in spring, using uniformly sized crowns set 18 inches apart and in rows some 5 feet apart.

OSU Extension Service community horticulturist Neil Bell said asparagus could be planted anytime in spring as long as the ground is easily workable. He said soil drainage and perpetual wet weather is more of a problem than cold. He recommends raised beds, which drain well.

Terra Gardens in Salem is selling 1-year-old plants, which look like a crown of roots. They have the asparagus varieties ‘Sweet Purple,’ ‘Mary Washington’ and ‘Jersey Knight’ for 99 cents each. 13th Street Nursery has ‘Jersey Knight’ plants for $1.49 each. Asparagus crowns also can be purchased from Territorial Seed Company for $36.95 for 25 crowns. They are shipped beginning in mid-April depending upon your location, and it is recommended to get orders in before March 15 for best availability.

In a trench about 6 inches deep, plant crowns about 12 inches apart. Spread the roots and cover the crowns with 2 inches of rich soil, amended with compost or slow-release fertilizer. Add lime if your soil is acid. As the spears lengthen through the season, fill the trench with soil.

Do not harvest the spears the first spring of planting. They should be left to form “ferns,” which provide food for the plant. The second spring after planting, a few shoots can be harvested, but only for a week or two. Leave the rest to feed developing roots. The third spring and thereafter, harvest spears until mid-June, then allow the fern to grow and keep the root crown healthy.

Asparagus should be fertilized in the spring as spears emerge and again right after the last harvest in June for older plantings.

Each crown can produce about a half-pound of edible spears per year when fully established.

“Asparagus is very drought-tolerant and can usually grow without supplemental watering because it seeks moisture deep in the soil,” according to an Ohio State University fact sheet.

Put rose pruning and planting on the calendar

The optimal pH for asparagus is 6.5 to 7.5. Weed growing beds thoroughly, and fertilize with a 10-20-10 formulation before planting.

“You can’t completely neglect it, but asparagus isn’t a high-maintenance plant,” Aegerter said. “It is susceptible to a few serious diseases, but for the most part doesn’t have high fertilizer needs. Its roots go deep, so it also doesn’t need the kind of watering that something like tomatoes would need.”

Weed control is the most challenging part of growing asparagus, said David Trinklein, an associate professor of plant sciences at the University of Missouri.

Give seeds a test for A+ performance

“Asparagus is a poor competitor with weeds,” Trinklein said. “On small plantings, very light cultivation with a hoe may be used to remove weeds, but avoid using power rotary tillers or any other tillage implements that can damage the crown, reduce yields and promote diseases.”

Use organic mulches liberally to suppress weeds, he said.

“When spears are 7 to 9 inches tall and still have tight tips, they are ideal for harvest,” Trinklein said. “When the leaves of the spears start to unfurl or ‘fern out,’ the spear is past its prime for eating.”

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 the emerging spears. Quality deteriorates rapidly after harvest. If you can’t eat your asparagus immediately, refrigerate or process it.

Varieties recommended for Oregon by Oregon State University include: Mary Washington, Jersey Knight, Jersey Giant, UC 157 and Purple Passion.

Forsythia, flowering quince call for annual pruning

Where to get asparagus

• Terra Gardens: ‘Sweet Purple,’ ‘Mary Washington’ and ‘Jersey Knight’ for 99 cents each, 9805 River Road NE, Salem, (503) 393-2131
• 13th Street Nursery: ‘Jersey Knight’ for $1.49 each, 1298 13th St. SE, Salem, (503) 363-4670
• Territorial Seed Company: ‘Jersey Knight’ and ‘Jersey Supreme,’ $36.95 for 25 crowns, shipped beginning in mid-April depending upon your location, territorialseed.com, (800) 626-0866