When to Plant Asparagus

Plant dormant crowns in early spring

Asparagus crowns, the bundled roots and buds of a one- or two-year-old plant, should go in while still dormant. The dates for your zone above run from about six weeks before the average last frost up to the frost date. University of Vermont Extension puts asparagus among the very hardy crops that can be planted 4 to 6 weeks before the frost-free date. The Rhode Island calendar plants crowns from about four weeks before the last frost through the frost date.

Timing is set by the buds, not by frost risk. Clemson warns that crowns planted too late in spring may begin sprouting before they go in, which can injure the developing buds.

The practical rule: plant as soon as the soil is dry enough to work, and don’t wait past your last frost date.

Regional timing

Cold North and the Intermountain West. Utah State plants crowns in April, and Maryland expects crowns to be shipped and planted in March or April. In the upper Midwest and northern New England, use the dates for your zone above and plant once the soil thaws and dries enough to dig a trench.

Mid-South and Southeast. Clemson gives two windows for South Carolina: February 1 to March 15 on the coastal plain, and March 1 to April 15 in the Piedmont. In Texas, Texas A&M plants 1- or 2-year-old crowns in January or February, or as soon as the ground can be worked.

Warm-winter areas (zone 9 and the low desert). Asparagus needs a dormant period, so it is marginal where winters are mild. Texas A&M says it does best in the cooler parts of North and West Texas and produces poorly where winters are mild and summers long and hot. In the Phoenix area, the University of Arizona calendar plants crowns from November to early February. UF/IFAS says asparagus is poorly suited to Florida, where spears are usually thin. Gardeners who try it there should plant one- or two-year-old crowns in the richest soil available and expect a modest crop.

Why not fall?

In cold climates, asparagus is planted only in spring. A spring crown has a full season to grow ferns and store food in its roots before its first winter. Texas A&M explains that this stored reserve supplies the energy for the next year’s spears. In fall, an established bed instead needs its ferns cut down and a layer of mulch. If you’re planning a new bed, fall is a good time to prepare it: Clemson wants any lime worked in during bed preparation at least three months before planting.

Planting from seed

Seed takes about a year longer to reach harvest than crowns, and it is slow in cold soil. Oregon State Extension found asparagus seed took about 53 days to come up at 50°F, 24 days at 59°F and 10 days at 77°F. For that reason, seed is started indoors in late winter. Utah State sows in January for April transplanting. Maryland transplants seedlings to the garden in June.

After planting: the timeline

The year you plant is year one, and there is no harvest. Maryland allows a light 3- to 4-week harvest in year two. Utah State waits until year three, and Clemson until year three or four. Harvest lengthens each year, up to about 8 weeks once the bed is mature. Whichever schedule you follow, plant in spring and let the ferns grow freely through the first full season, so the crowns go into winter well fed.

See how to grow asparagus for trench depth, spacing, fertilizer and long-term care.