Asparagus
Dates below are counted from the average last spring frost or the average first fall frost. Enter a ZIP in the calendar for NOAA 1991–2020 station averages, or pick a zone and use the zone table.
When to plant
Soil and site
Choose a permanent bed with full sun, deep loose soil, and sharp drainage. Cornell prefers a pH near 7 and says to avoid frost pockets, because a late frost can kill emerged spears. Clemson prepares the bed with compost and aims for pH 6.0–6.5.
Seedlings
Plant disease-free 1-year-old crowns. Cornell's window is 4–6 weeks before the average last frost; the calendar uses the middle of that range. Set crowns 18–24 inches apart in a trench about 8 inches deep (5 inches for Jersey series), spread the roots, and cover with 1–2 inches of soil. Fill the trench in gradually as the ferns grow.
In the garden
Clemson sets crowns 15–18 inches apart and 6–8 inches deep, a bit tighter and sometimes shallower than Cornell. Do not harvest the planting year. Let the ferns die back on their own before you cut them.
Picking
Clemson says to wait until the third or fourth year for a light harvest of 3–4 weeks, and to take spears at 6–8 inches before the tips open. Cut or snap at the soil surface. A Cornell Cooperative Extension summary counts about 2 years from planting crowns to a crop, so the two extensions do not agree on the first picking year.
Harvest
Cornell Cooperative Extension counts about 2 years from planting crowns to a crop. Clemson says to wait until the third or fourth year, then harvest lightly for three to four weeks. Those year counts are not converted into days here.
Take spears at 6–8 inches, before the tips open. Cut or snap them at the soil surface. Stop when spears shrink to pencil size and let the ferns grow. Do not harvest the planting year.
Preserving
Plain asparagus is a low-acid vegetable. The tested method is pressure canning. Do not can it in a boiling-water canner.
USDA's tested method for asparagus spears or pieces is pressure canning. Use the linked tables for jar size, time, and altitude. This page does not repeat those numbers.
National Center for Home Food Preservation: Asparagus, spears or pieces →Freeze young spears with the NCHFP method, including the blanch on that page.
National Center for Home Food Preservation: Freezing asparagus →A home freeze-dryer can dry this crop, but USDA has not published a canning-style time for it. Follow the appliance manual for load and cycle length, then store the dry food sealed. Freeze-drying is not a substitute for a tested canning process.
Appliance manual (no USDA process time)
Canning, pickling, and fermenting notes here are summaries of tested USDA and National Center for Home Food Preservation methods. Times, pressures, and amounts live only on those pages. This site does not publish home-invented processing times.
Gear placeholders
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- Placeholder: seeds for Asparagus
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- Placeholder: home freeze dryer
Dates by zone
These pages turn the same frost offsets into calendar dates for each zone the calendar covers.