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Planting and Growing Asparagus

Organic farming asparagus in black soil gardening plants growing
Image Credit:
KarepaStock/Shutterstock
Botanical Name
Asparagus officinalis
Grown as
Perennial
USDA Zones
3a
3b
4a
4b
5a
5b
6a
6b
7a
7b
8a
8b
Toxicity
Non-toxic
Sun Exposure
Full Sun
Water Needs
Moderate
Height
3-6 feet
Spread
3-6 feet
Soil pH
Neutral
Bloom Time
Spring
Flower Color
Yellow
Special Features
Cut Flower
Low Maintenance
Attracts Songbirds
Deer-resistant
Rabbit-resistant
Resilience
Cold Hardy
Salt Tolerant
Plant Type
Vegetables
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Asparagus is the gift that keeps on giving! This spring superstar pops up early in the season and rewards your patience with crisp, green spears year after year. 

Once it’s established, it’s like planting your future meals. Here’s how to grow asparagus—from planting all the way through harvesting!

Asparagus can be grown in most temperate regions, but more robustly in cooler areas with long winters. The edible part of the asparagus plant is the young stem shoot, which emerges as soil temperatures rise above 50°F (10°C) in spring. 

If you are starting asparagus for the first time, plant 5 to 10 plants per person (15 to 30 feet per row).

How Long Does It Take to Grow Asparagus?

As mentioned above, newly planted asparagus plants may take 2 to 3 years to start producing, so patience is truly needed! Once established, however, asparagus can be productive for decades.

In addition, asparagus plants are relatively fast producers, sending up new spears every few days for a few weeks in the spring. The plant produces ½ pound of spears per foot of row in spring and early summer, so we think it’s definitely worth the wait.

The most important thing to know about asparagus is that you should not harvest it during the first couple of seasons. These plants need to be established before you can harvest sustainably. The patience is well worth it, though. Asparagus beds can be productive for 15, 20, and sometimes up to 30 years. 

Because asparagus stays productive for so long, it’s essential to plant the best variety available for your area. (See recommended varieties below.)

Planting

When to Plant Asparagus

  • Asparagus is usually grown from 1-year-old plants called “crowns,” planted about 2 to 4 weeks before your last spring frost date. Many gardeners plant them at about the same time as potatoes.
  • We do not recommend growing from seed; it takes about three years to mature enough to harvest. If you plant crowns, you can shorten the wait time by a year and eliminate one year of tedious weeding. However, if you’re truly eager to experiment and have a lot of patience and time, our colleague Robin wrote about planting asparagus by seed.

Asparagus spacing

Where to Plant Asparagus

Given that asparagus is a perennial plant that comes back year after year in the same spot, it’s important to select a proper planting site where it will thrive.

  • Choose a site that gets full sun (6 to 8 hours of direct sunlight).
  • Place the asparagus bed toward the edge of your garden, where it will not be disturbed by the activity of planting and replanting in other areas.
  • Ensure the bed will drain well and not pool with water. Asparagus does not like to have its roots get too wet. If you do not have a site with good drainage available, consider growing asparagus in raised beds instead. Learn how to make a raised garden bed here.
  • Asparagus thrives in neutral to slightly acidic soil (pH of about 6.5).
  • Eliminate all weeds from the planting site, digging it over and working in a 2- to 4-inch layer of compost, aged manure, or soil mix. (Learn more about soil amendments and preparing soil for planting.)
  • The soil should be loosened to 12 to 15 inches in depth to allow the asparagus crowns to root properly and not be disrupted by rocks or other obstacles. 

How to Plant Asparagus

  • Plant crowns deeply to protect them from the cultivation needed for annual weed control.
  • Dig a trench about 12 to 18 inches wide and 6 to 8 inches deep. If digging more than one trench, space the trenches at least 3 feet apart.
  • Soak the crowns briefly in lukewarm water before planting.
  • Make a 2-inch-high ridge of soil along the center of the trench. Place the asparagus crowns on top of the mound, spreading out their roots evenly.
  • Space asparagus crowns 12 to 18 inches apart (measured from root tip to root tip) within the trench.

Once you get to this point, you can follow one of two planting methods: the traditional “little-by-little” method or the easier “all-at-once” method.

“Little-by-Little” Method:

Once the trenches are dug and the crowns are set out:

  1. Cover the crowns with compost and topsoil, burying the crowns 2 inches deep. Water in.
  2. As the season progresses and spears grow to be 2 to 3 inches tall, add 2 more inches of soil to the trench, being careful not to bury the spears completely.
  3. Once the spears again grow through the layer of soil, add an additional 2-inch layer of soil. Repeat this process until the trench has been filled to ground level. Depending on how deep you dug your trench, you may need to add soil 1 to 2 more times throughout the season.
  4. After you’ve filled the trench completely, mound the soil slightly to prevent water from pooling around the emerging spears.

“All-at-Once” Method:

  • Some gardeners simply fill in the trench with soil and compost all at once. While it’s thought that the traditional method results in stronger plants overall, gardeners don’t typically have any issues resulting from the “all-at-once” method. As long as the soil is fairly loose, the spears won’t have a problem pushing through to the surface.

Learn how to plant and grow an asparagus bed in our video:

Growing

  • When the trench is filled, we would recommend adding a 4- to 6-inch layer of mulch.
  • The biggest issue with asparagus is managing weeds during the first 2 years. Asparagus should not have its roots disturbed, so you’ll need to gently hand-pull weeds, taking care not to disturb asparagus’ roots. Weeds will become less of an issue as the plants fill in. Mulch around the plant with compost or grass clippings to help retain soil moisture and reduce weed growth.
  • During the first 2 years after planting, asparagus plants need 1 to 2 inches of water per square foot per week. If you are not receiving adequate rainfall, you will likely need to water. Use drip irrigation if possible.
  • Asparagus thrives on a steady supply of plant food. Consider an organic fertilizer during the growing season. Follow the instructions on the label of whatever product you use.
  • Do not harvest the spears in the first or second year (the plant needs time to grow out its root system), but cut down dead foliage in late fall and side-dress with compost.
  • During the second year, side-dress with compost in spring and early fall and cut down dead ferns in late fall. Keep the bed thickly mulched.
  • During the third year, the bed should be in full production so you can start to harvest asparagus sparingly throughout the season.

How to Transplant Asparagus

  • If you must move asparagus, transplant the crowns in early spring when they are dormant or in late fall before the first fall frost (after the foliage is cut back).
  • Dig and lift crowns with a garden fork, careful not to disturb the roots.
  • Divide the clump into two or more pieces.
  • Water transplants.
  • Do not harvest heavily in the following year.

Harvesting

  • Skip the harvest in the first year and the second year, if possible. Ideally, wait three growing seasons before harvesting in order to allow the crowns to become fully established.
  • If you have young plants, the season may last 2 to 3 weeks. However, established plants produce longer—up to 8 weeks.
  • Check your plant every other day for harvest-ready spears. Spears grow quickly and may become too woody before you know it! Once an asparagus spear starts to open and has foliage, it’s too tough for eating.
  • Harvest spears when they reach 8 to 10 inches in height and between 1/2 and 3/4 inch thick. (Bear in mind that younger, thinner spears will be more tender, so harvest according to your own taste.)
  • To harvest asparagus, simply cut the spears with a sharp knife or scissors at ground level.
  • Stop harvesting spears when the diameter of the spears decreases to the size of a pencil.
  • After harvest, fertilize your asparagus patch in the early summer. You can top-dress with a balanced organic fertilizer or scatter another inch of rich, weed-free compost over the decomposing mulch.
  • Do NOT cut down the remaining ferns in summer or you will ruin your asparagus bed. Allow the ferns to grow and mature; this replenishes the nutrients for next year’s spear production. Always leave at least two or three spears on the plant through the growing season.
  • Only cut back asparagus ferns AFTER the foliage has died back and turned brown or yellow. This is usually in early winter after several hard freezes. Cut the ferns back to the ground.
  • Fertilize the bed with a 1-inch layer of rich, weed-free compost or manure topped with 3 inches of straw, rotted sawdust, or another weed-free mulch. Clean spears will push up through the mulch in spring.
Asparagus colors: purple, white, and green
Asparagus comes in few different colors: purple, white, and green! Photo credit: Picture Partners/Shutterstock

How to Store Asparagus

  • Plunge just-cut spears into cold water immediately to preserve their sugar content.
  • Asparagus does not keep for very long after it’s picked, so be sure to eat it within 2 or 3 days from harvest.
  • To store, bundle the spears together, wrap the stem ends of the spears in a moist paper towel, and place the bundle in a plastic bag. Store in the crisper drawer of your refrigerator.
  • If you have enough space in your fridge, you can also store asparagus by placing the spears in a cup of water. Keep about an inch of clean water in the cup.

Pests and Problems

One of the biggest concerns in the asparagus bed is simply weeds. Hand pulling should be done regularly in spring and early summer. Cultivate lightly to avoid damaging emerging asparagus spears. Applying 4 to 6 inches of straw in summer also effectively controls weeds.

Asparagus Pests and Diseases
Pest/DiseaseTypeSymptomsControl/Prevention
Asparagus beetlesInsectSpears turn brown and bend in a hook shape; defoliationRemove beetles by hand; dispose of plant matter in the fall where eggs could be housed
Asparagus rust FungusPale green spots on emerging spears become yellow/orange with concentric rings; reddish-brown blisters appear in summer, releasing rust-colored spores that turn black; brown ferns; defoliation; reduced vigorRust requires moisture to spread; avoid getting excess water on spears or ferns. Destroy infected plant matter; choose resistant varieties; ensure good air circulation; avoid planting new asparagus nearby
CutwormsInsectWilting; stems of young spears severed (“cut”) just above soil lineWatch for cutworms and remove by hand; clear away weeds and other plant matter. Find more cutworm prevention tips here.
Fusarium crown rotFungusYellow, stunted, wilted ferns; reddish-brown spots on lower stems, crowns, or roots; rotting spearsDestroy infected plants; avoid planting new asparagus nearby infected site for 5+ years; choose resistant varieties; disinfect tools to prevent spread; avoid overharvesting
Slugs/snailsMolluskIrregular holes in spears; slimy secretion on plants/soilHandpick; avoid thick bark mulch; use copper plant collars; lay boards on soil in evening, and in the morning dispose of “hiding” pests in hot, soapy water; drown in deep container filled with 1/2 inch of beer, or sugar water and yeast, and sunk so that top edge is slightly above ground; apply a 1-inch-wide strip of food-grade diatomaceous earth as a barrier

Asparagus is considered a deer-resistant plant, though deer may nibble on the tips of fresh shoots. A hungry deer will eat almost anything!

Types

Asparagus plants are either male or female. Female plants produce berries; male plants do not expend energy on berries, so they can be up to three times more productive than female plants. For this reason, growing male asparagus plants is often preferred. 

  • Gardeners in Zones 4 to 6 have a wider selection of varieties, including ‘Jersey Giant’, ‘Jersey King’, and ‘Jersey Knight’. Older varieties ‘Mary Washington’ and ‘Martha Washington’ may produce female plants, which are not as productive as the males.
  • In colder climates, ‘Guelph Millennium’ and other varieties that emerge late often escape damage from spring freezes.
  • In warmer climates, early and heat-tolerant varieties such as ‘Apollo’ and ‘UC-157’ produce well before the weather turns hot.

White asparagus is not a variety but simply asparagus grown in the absence of sunlight to prevent chlorophyll from developing. White asparagus is slightly sweeter but has less fiber than green asparagus.

Purple asparagus is bred to be purple in color but turns green when it is cooked. Purple varieties tend to have thicker spears, but fewer of them. ‘Purple Passion’ is tasty but is not an all-male variety.

White asparagus

Wit and Wisdom

Vegetables

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening, so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Rich</span> Thu, 04/28/2016 - 19:43
That is hilarious. I guess I'm not the only one...
<span>Linda Diane</span> Thu, 04/14/2016 - 15:59
I have shoots (fern-like) coming up all over my garden. Will they ever produce or should I just pull them all up.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 04/18/2016 - 09:04

So, we're thinking that you didn't plant asparagus, so you don't know if this is asparagus.
Do you have any spears? Spears would be making an appearance, too.

One way to see what this is, because it may not be asparagus (we have no way of knowing for certain) is to dig up an area. If there is a "crown" from which the ferns come, with long roots going deep into the ground beneath it, this may be asparagus. The crown is a fairly substantial centerpiece; the roots are numerous and deep. (You do not need to unearth all of the roots.)

If it is not asparagus, take the unearthed plant, with the fern-like top, to a local nursery. They may be able to identify it for you.

 <span>Rhonda Cox</span> Sun, 04/10/2016 - 12:25
I'm in S.C., planted asparagus last spring it grew about 3-4 ft tall. I cut it back for fall and we covered it for winter. Upon uncovering recently, the stalks are several feet long and bending over. We added fertilized soil, manure, and mulch My questions is, what do I do now with it bending over? Appreciate any further info you can give me.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 04/11/2016 - 11:59

We are thinking that by "bending over" you mean that the spears are spindly—thin, weak. This is usualy a sign that the crowns were not planted deep enough; that they are shallow. Depth should be 6 to 8 inches (we say 6 above; close enough). It also strikes us that you might have soil imbalance (did you check pH? do a soil test?); asparagus loves rich organic matter but too much of any/some nutrients—fertilizer and manure, for example—could contribute to the spindliness by "getting them going," so to speak, faster than nature would have it happen.

 <span>Rhonda</span> Tue, 04/19/2016 - 15:21
Both thick and thin are bending over. I've done soil tests in the past but, last year put in raised beds with fertilized soil and Black cow. I mulched with red mulch. can or, should I stake them or, (sadly) start over?
<span>Dee</span> Fri, 04/08/2016 - 13:45
I bought asparagus roots last Fall and was unable to get them in the ground on time. I am wondering if it is too late to plant them this Spring? The roots look dried out... should I soak them in water and "SUPERthrive" to revive them? Will that work? I really do not want to throw them away... can they be salvaged? I live in Zone 8, and I am waiting until April 15 to plant any thing. We keep getting cold spells and they burned some Asiatic Lilies that started coming up, so I think that it may have killed them. So I don't want to plant my veggies or Asparagus until then. Anyway. Please let me know ASAP, because it is now April 8, so it is getting close to that time. Can I make these roots grow? Thanks.
<span>Andrew Jenkins</span> Sat, 05/28/2016 - 12:03
Well... I have exactly the same issue. I wish someone would have answered this question, cause it would have been extremely helpful. I guess I'll just throw them in the ground, so to speak, and see what happens... :|
<span>Heidi</span> Wed, 10/12/2016 - 14:53
I was new to asparagus and knew nothing about ideal planting times. In fact I don't even like asparagus but wanted to try the purple. So, brought home some one year dried crowns from the store but didn't bother getting them in the ground immediately. Finally got around to digging the trenches and stuck a few in the ground. One or two took immediately and others didn't, so I pulled them, soaked them in water with a little rooting powder and stuck them back in the ground. BAM! I planted end of June, it's now October and I have some super fluffy 3-4' healthy ferns (even a few spears I am letting grow) - still have new ferns emerging. I'm placing all my pulled tomato and bean plants around roots now to over winter and I'm pretty sure I'll have a small harvest next year. Don't give up- two of the crowns took about 6 weeks to sprout.
<span>Kate W</span> Mon, 04/04/2016 - 08:32
I would like to improve the bed for my well established asparagus by framing the bed and building it up with soil, to enrich what is there. Will this work? Is there a danger to the plants and how they grow through the surface soil?