CORVALLIS, Ore. – 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.
In a trench about six inches deep, plant crowns about 12 inches apart. Spread the roots and cover the crowns with two 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.
To harvest, grasp five- to eight-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.
Information on how to pickle asparagus is in the online OSU publication, PNW 355 "Pickling Vegetables."
Varieties recommended for Oregon by OSU include: Mary Washington, Jersey Knight, Jersey Giant, UC 157 and Purple Passion.