Grow your own asparagus; here's how
Question: I’d like to plant asparagus. How many years until it bears? When do you plant it?
Answer: February is the time to order asparagus crowns, which mature a year or two faster than seed. And our relatively dry weather we’ve been having will allow you to work up a new bed.
Choose a sunny site, and amend the soil deeply with plenty of organic matter. Asparagus will not grow well in heavy, poorly drained soils, such as clay.
Be sure to add plenty of compost. Then, around mid-March, plant crowns.
Planting a new asparagus bed is a great example of delayed gratification, as the crowns need a couple of years to mature into a fully harvestable patch.
Fortunately, asparagus is a perennial vegetable, so your efforts will pay off for many years to come. A healthy asparagus patch may yield luscious green (or purple) spears for decades.
An added incentive is that homegrown asparagus is way less expensive and much better quality than store-bought spears, which sometimes tend to be woody and tough.
Asparagus crowns are for sale in early spring. Territorial Seed Company offers them beginning in mid-March. The company has a variety called Pacific Purple that I love. Its dark purple spears are so tender they can be eaten raw or cooked. Pacific Purple supposedly outperforms and yields more than most other green varieties, with thicker, tender stringless spears that are higher in sugars and anthocyanins. The purple color fades with cooking.
Once you get the crowns, plant them into the ground as soon as possible. The crowns that you purchase for planting often are the roots gleaned from 1-year-old plants. Crowns offered for planting have long fleshy roots extending from a central axis.
Oregon State University Extension horticulturists recommend planting asparagus in a trench about 6 inches deep, planting crowns about 12 inches apart. Spread roots, and cover the crowns with 2 inches of soil amended with compost or slow-release fertilizer. Add lime if soil is acidic. As the spears lengthen, fill the trench with soil.
Male plants usually are more productive than females, which produce seed that tend to sprout all over. Reputable companies, such as Territorial Seed, offer predominantly male plants.
The OSU Extension Master Gardeners recommend refraining from harvesting spears their first spring. Their “ferns” provide food for the plant. The second spring after planting, a few shoots can be harvested, but only for a week or two, then the rest should be left to feed developing roots. The third spring and thereafter, spears can be harvested until mid-June, then allow the fern to grow and keep the root crowns healthy. Thereafter, fertilize asparagus as the spears emerge each spring and after the last harvest in June.
Carol Savonen is a naturalist and writer. She is an associate professor emeritus at OSU and tends a large garden in the Coast Range Hills west of Philomath with her husband and dogs. She can be reached at Carol.Savonen@oregonstate.edu or c/o: EESC, 422 Kerr Admin. Bldg., OSU, Corvallis, OR 97331.
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