How to Grow Asparagus
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If you want to know how to grow asparagus, plan on patience. Crowns need time to build their root systems before they can carry a harvest, and a well-managed bed can keep producing for more than a decade. The setup itself is straightforward: a sunny site with good drainage, healthy crowns, a trench, and a clear rule for when to start cutting.
This guide draws on four extension publications opened on 2026-10-23: Colorado State University Extension, N.C. Cooperative Extension in Pamlico County, Virginia Tech Cooperative Extension, and Montana State University Extension. They agree on site, crowns and fern care. They disagree on fertilizer rates, row spacing and when the first full harvest begins, so the table below shows each figure.
Quick answer
- Choose a sunny spot with well-drained soil, and plant one- or two-year-old crowns in early spring.
- Set crowns 12 to 18 inches apart in a trench, with rows roughly 2.5 to 5 feet apart, depending on the source. Cover them lightly and fill the trench as shoots grow.
- Do not harvest in the first year. Harvest lightly in the second year, and expect a full harvest of about 4 to 8 weeks by year three, depending on the source.
- Let the ferns grow after harvest, and cut them down only when they turn brown in fall.
Choose the site and the crowns
Asparagus wants sun and good drainage. Colorado State advises a sunny spot that gets at least eight hours a day, and it says the soil should drain well so the plants can grow undisturbed. Virginia Tech says to choose a site with good drainage and full sun, and it warns that the tall ferns can shade other plants, so plan the bed’s position with that in mind. NC State adds that the site should be relatively free of perennial broadleaf weeds and nutsedge.
Crowns are the usual start. Colorado State says the easiest route is bareroot crowns or crowns already growing in pots, and it recommends crowns with 8 to 10 large roots and one or two healthy bud clusters. Virginia Tech says to start from one- or two-year-old crowns, and it notes that crowns from a reputable nursery give the fastest results. Montana State recommends crowns that are dormant and have large, fleshy, whitish-tan roots without mold or rot.
Seed is possible, but it takes longer. Virginia Tech states that “Starting plants from seed requires an extra year before harvest.” Montana State advises buying one- or two-year-old crowns, or dividing and transplanting old crowns and leaving one bud per division.
Prepare the bed and pick a variety
Prepare the bed before you plant. NC State says to test the soil at least six months before planting, sampling to a depth of 12 inches, and to adjust it to a pH between 6.7 and 7.0. It adds that asparagus grows poorly in acidic soils. Colorado State suggests working four inches of well-composted organic material into the top twelve inches of soil before planting. Montana State recommends working 50 to 100 pounds of rotted organic matter or compost per 100 square feet into the soil, and it asks for weeds to be cleared first.
Heavy soil needs extra work. Virginia Tech says double digging is recommended in heavy soils, and that the extra work is worth the effort because a 12-inch-deep trench is usually dug anyway. Virginia Tech also suggests adding leaf mold or compost at a rate of 20 percent by volume.
Variety choice matters for yield. NC State explains the reason for all-male hybrids: “The female plants expend more energy to produce seeds; therefore, the female plants will have a much lower yield than the males.” It names Jersey Knight as an all-male hybrid. Colorado State lists Jersey Giant, Jersey Knight, Purple Passion, Millennium and the Washington series as recommended for its area of Colorado, so choose varieties that your local extension recommends.
Plant the crowns
Trench planting is the method most of these guides describe. Colorado State says to dig a trench six inches deep, set the crowns 12 to 18 inches apart with the buds facing up, and cover them with just one or two inches of soil. As the shoots grow, Colorado State advises filling the trench slowly, one or two inches a week, until it is level with the rest of the bed.
The spacing figures differ, so the table below sets them side by side.
| Source | Spacing in the row | Between rows | Trench or planting depth |
|---|---|---|---|
| Colorado State | 12 to 18 inches | Not stated | Trench 6 inches deep |
| NC State, Pamlico County | 12 to 18 inches | 5 feet | Furrow 6 inches deep |
| Virginia Tech | 18 inches | 4 to 5 feet | Trench usually 12 inches deep |
| Montana State | 18 inches (mounds) | 2.5 to 3 feet | Trench 10 inches deep |
NC State gives a planting date for its region: in eastern North Carolina, the crowns go in during February in a furrow six inches deep, with two inches of soil over the crowns. As the plants grow, pull soil around them gradually until the trench is filled. NC State says this slow fill keeps compaction low above the crowns, which aids spear emergence.
Water, feed and mulch
Water steadily while the bed establishes. Colorado State says to water one to two inches per week during the first two years. Mulch with two to three inches of organic material, which Colorado State says keeps the soil moist, stops weeds and protects the crowns in winter.
Feeding rates differ between sources. Colorado State calls asparagus a heavy feeder and recommends a 10-16-8 fertilizer in spring as growth starts, with another application in mid-summer after harvest. NC State recommends a complete fertilizer such as 5-10-10 broadcast on the bed just before the spears start to grow, with a second application at the end of the cutting season. Montana State recommends nitrogen early each spring, at 1 to 2 and a half pounds of actual nitrogen per 1,000 square feet unless the soil is rich in organic matter. Use a soil test to choose the rate for your bed.
Cultivate carefully. NC State says to cultivate to control grass and weeds, but it warns that crowns and roots can be damaged even by shallow cultivation. Virginia Tech recommends weeding each spring before the first shoots come up, so that you do not break off spears by mistake.
The first three years: when to start cutting
Patience is the rule in year one. Colorado State says not to harvest any spears for at least the first two years, so the crowns and roots can develop. NC State says not to harvest in the first growing season after planting. Virginia Tech adds that starting from seed adds a year to the wait.
Year two is for light cutting. NC State says to harvest for no more than two weeks in the second year. Virginia Tech says to harvest lightly for three to four weeks. Montana State says to harvest only lightly in the second year, with the first full harvest in the third season.
Year three is where the sources diverge, and the table below shows each one.
| Source | Year 1 | Year 2 | Year 3 | Year 4 |
|---|---|---|---|---|
| Colorado State | No harvest | No harvest for at least two years | 4 to 6 weeks, early May to mid-June, at two or three years | Not stated |
| NC State, Pamlico County | No harvest | Up to two weeks | 6 to 8 weeks | Not stated |
| Virginia Tech | No harvest | Light, three to four weeks | Not stated | 8 to 10 weeks |
| Montana State | No harvest | Light only | First full harvest, up to six weeks | Not stated |
The sources also disagree on spear size. Colorado State says to harvest only spears larger than a pencil. Montana State says to cut spears when they are eight to 10 inches tall, and Virginia Tech says the 6- to 8-inch spears are best. The sizes do not match, so pick a size and cut consistently.
Harvest the spears correctly
Harvest is a daily job during the cutting window. Virginia Tech says to harvest spears daily during the 8- to 10-week harvest period. Montana State describes the method: snap the spears off at the soil line or cut them with a sharp knife at or just below the soil line, and “Don’t cut deep enough to damage the crown.” Virginia Tech also warns that cutting too deeply can injure the crown buds that produce the next spears.
Stop on schedule. Montana State says to “Cut spears for no more than the first six weeks”, and to stop when the spears get noticeably thinner. NC State says weak plants should be harvested for less time. Virginia Tech says the bases of spears left too long become tough and need to be cut off.
Protect the crowns during the harvest. Montana State says that “No planting of asparagus will last long if all spears are removed every season.” Let the remaining spears grow into ferns, which feed the roots for the next year.
After harvest and through winter
Let the ferns grow. Colorado State says to let the ferns grow until fall and stand through winter, then trim them back in spring before new spears appear. NC State advises waiting until the ferns turn brown before cutting them down, because cutting them earlier reduces the next year’s crop. Montana State says the sugars made by the ferns return to the roots as they die back, so leaving them to brown matters.
Mulch for winter. Montana State recommends an insulating mulch of straw after the soil freezes, then removal in early spring once the danger of severe cold has passed, because mulch left on too long keeps the ground cool and delays the spears. Virginia Tech says to mulch perennial asparagus in autumn. Colorado State says the organic mulch helps protect the plants in winter.
Plan a yearly compost top dressing. Virginia Tech suggests topdressing with compost each year in late winter or early spring, and it recommends a fertilizer plan based on soil test results. Montana State says the same bed can produce for 12 to 15 years when it is managed properly.
For soil volume and bed setup, see our guide to how much soil a raised bed garden needs. Winter care for perennial beds is covered in our post on preparing raised beds for winter.
Common mistakes and how to avoid them
- Cutting in year one. Virginia Tech says plants harvested too heavily too soon often become weak and spindly, and the crowns may never recover.
- Cutting spears too deep. Montana State warns not to cut deep enough to damage the crown, and Virginia Tech says deep cuts can injure the crown buds.
- Cutting ferns before they brown. NC State says early cutting reduces the next crop of spears.
- Leaving winter mulch on too long. Montana State says the mulch keeps the ground cool and delays emergence if it is not removed.
- Skipping the soil test. NC State recommends a soil test at least six months before planting, and it says asparagus grows poorly in acidic soils.
How we chose
These sources are extension publications that describe growing asparagus from crowns step by step. Each page was opened with curl on 2026-10-23 and returned HTTP 200. Virginia Tech and Montana State give the most detailed guidance on harvest and maintenance. Colorado State is the most concise on crown selection and early care. NC State adds a regional planting window and the reasoning for all-male varieties.
The post recommends no products. Where the sources disagree on spacing, fertilizer, year-three harvest or spear size, the differences appear in the tables and the text. The sources’ pest and disease sections were read but are not used here.
What we could not verify
This section separates what the sources state from what they leave open. Where a source gives no number, this post gives none.
What the sources do not say
The sources we opened do not agree on the first year of harvest in year three. Colorado State says two or three years, NC State says year three at six to eight weeks, Montana State describes year three as the first full harvest, and Virginia Tech gives no year-three figure. The table above shows each one.
They do not agree on how long a bed will last. Colorado State says 10 to 15 years, NC State says 15 years or more, and Virginia Tech says 12 to 15 years or longer. Montana State notes that a well-managed bed can still be fairly productive after 30 years.
They do not give a yield for home beds. Montana State gives a peak yield of five pounds of spears per 100 square feet, and it does not say how that figure applies to a backyard bed. The sources we opened do not address pests or plant diseases in detail, so this post offers no guidance on either.
Frequently asked questions
How long does asparagus take to produce?
Most sources expect a wait of at least two years before cutting. Colorado State says not to harvest for at least the first two years, and some sources suggest three. Virginia Tech says seed-grown plants need an extra year.
Can you cut asparagus in the first year?
No. NC State says not to harvest in the first growing season after planting, and Colorado State and Montana State say the same. Harvesting too soon leaves plants weak.
When should the ferns be cut back?
Wait until the ferns turn brown in fall. NC State says cutting ferns before frost reduces the next crop, and Montana State says to leave them until they are browning.
How tall should spears be when cut?
The sources differ. Colorado State says spears larger than a pencil, Montana State says eight to 10 inches tall, and Virginia Tech says 6 to 8 inches is best. Choose a size, cut at the same length through the season, and stop when the spears thin out.
How far apart should crowns be planted?
Most sources give 12 to 18 inches in the row. Virginia Tech and Montana State use 18 inches, and NC State and Colorado State use 12 to 18 inches. Row spacing ranges from about 2.5 feet to 5 feet, depending on the source.
Sources
- Colorado State University Extension, Growing Asparagus in the Home Garden: https://extension.colostate.edu/resource/growing-asparagus-in-the-home-garden (opened 2026-10-23)
- N.C. Cooperative Extension, Pamlico County Center, Growing Asparagus in the Home Garden: https://pamlico.ces.ncsu.edu/2023/02/growing-asparagus-in-the-home-garden (opened 2026-10-23)
- Virginia Tech Cooperative Extension, Publication 426-401, Asparagus: https://pubs.ext.vt.edu/426/426-401/426-401.html (opened 2026-10-23)
- Montana State University Extension, MontGuide MT198365AG, Asparagus in the home garden: https://extension-store.montana.edu/montguides/asparagus-in-the-home-garden (opened 2026-10-23)
