Growing Asparagus

Planting, Growing, and Harvesting Asparagus

Asparagus is one of the first plants that greets us in springtime! It’s a perennial, which means that once it gets established, the tender spears will return year after year. In addition, its ferny foliage makes an excellent ornamental. Here’s how to grow asparagus—from planting through harvest.

Asparagus can be grown in most parts of the country but grows more robustly in cooler regions with longer winters. The edible part of the asparagus plant is the young stem shoot, which emerges as soil temperatures rise above 50 degrees Fahrenheit in spring.

The most important thing to know about asparagus is that you really should not harvest it for the first couple seasons. Plants need to be allowed to mature before you can harvest. The patience is rewarded because the asparagus bed will be productive for 15, 20, sometimes 30 years.

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

Plant in early spring as soon as the soil can be worked. Asparagus is usually grown from 1-year-old plants or “crowns” (bought at a garden center) but it can also be grown from seed. Starting with asparagus crowns, however, eliminates the year of tedious weeding that comes with starting from seed.

If you are starting asparagus for the first time, we would plant 10 to 20 asparagus plants per person (15 to 30 feet of row).

How Long Does It Take to Grow Asparagus?

As said above, newly-planted asparagus plants may take 2 to 3 years to truly get started and produce, so patience is needed! After they’re established, however, asparagus is productive for decades.

In addition, asparagus plants are fairly 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.

Planting

When to Plant Asparagus

Plant asparagus crowns in the early spring, as soon as the soil can be worked. Many gardeners plant about the same time potatoes go in the ground.
A few varieties, such as open-pollinated ‘Purple Passion’ and hybrid ‘Sweet Purple,’ can be grown from seed. Start seeds indoors in spring and set out the seedlings when they are 12 to 14 weeks old, just after your last spring frost.
1. Soak seeds in water for up to 24 hours before sowing.
2. Sow seeds in moistened peat or seed-starting soil in flats or peat cups.
3. Once plants reach 12 inches in height, harden them off outdoors for a week.
4. After the last spring frost, transplant the young plants to a temporary garden bed. Once they mature in the fall, identify the berry-less male asparagus plants and transplant them to your permanent planting site, removing the less-productive female plants.

Choosing and Preparing a Planting Site

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 has at least partial sun.
Place the aspargus bed toward the edge of your garden where it will not be disturbed by the activity of planting and re-planting other areas.
Ensure the bed will drain well and not pool water. Asparagus does not like to have its feet “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 netural 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 of 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 and place the asparagus crowns on top of the mound, spreading their roots out evenly.
Within the trench, space asparagus crowns 12 to 18 inches apart (measured from root tip to root tip).

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:

Cover the crowns with compost and topsoil, burying the crowns 2 inches deep. Water in.
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.
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.
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 result from the “all-at-once” method, either. 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:

Care

Caring for Asparagus

When the trench is filled, we would add a 4- to 6-inch layer of mulch.
The biggest issue with asparagus is managing weeds during the first two years. Asparagus can not have its roots disturbed so you’ll need to gently hand pull weeds, taking care not to disturb roots. Weeds will become less of an issue as the plants fill in. Mulch around the plant with compost or grass clippings to help soil moisture and reduce weed growth.
During the first 2 years after planting, asparagus plants need 1 to 2 inches per week. If you are not receiving adequate rainfall you will need to water. Use drip irrigation if possible.
Asparagus thrive on a steady supply of plant food. Consider an organic fertilizer during the growing season. Follow the label on the product.

Before Harvesting

Do not harvest the spears in the first 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, harvest for only 3 to 4 weeks, side-dressing with compost in spring and early fall and cutting 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.

Transplanting Asparagus

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

Pests/Diseases

One of the biggest concerns in the asparagus bed is simply weeds. Hand pulling should be done on a regular basis in spring and early summer. Cultivate lightly to avoid damaging emerging asparagus spears. The application of four to 4 to 6 inches of straw in summer also is effective in controlling weeds.

Insect Pests and Diseases

Pest/Disease	Type	Symptoms	Control/Prevention
Asparagus beetles	Insect	Spears turn brown and bend in a hook shape; defoliation; damaged fruit/seeds	Remove beetles by hand; dispose of plant matter in the fall where eggs could be housed
Cutworms	Insect	Wilting; stems of young spears severed (“cut”) just above soil line	Watch for cutworms and remove by hand; clear away weeds and other plant matter. Find more cutworm prevention tips here.
Fusarium Crown Rot	Fungus	Yellow, stunted, wilted ferns; reddish-brown spots on lower stems, crowns, or roots; rotting spears	Destroy infected plants; avoid planting new asparagus nearby infected site for 5+ years; choose resistant varieties; disinfect tools to prevent spread; avoid overharvesting
Asparagus Rust	Fungus	Pale 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 vigor	Rust 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

Asparagus is considered a deer-resistant plant, though a hungry deer will eat almost anything.

Harvest/Storage

How to Harvest Asparagus

Do not harvest the first couple seasons (see information above).
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 have foliage, it’s too tough for eating.
Harvest spears when they reach 8 to 10 inches in height and between ½ and ¾ 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 in 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 ferns 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 one or two spears.
Only 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 in field

How to Store Asparagus

Asparagus does not keep for very long after it’s picked, so be sure to eat it within two or three days from harvest.
Brush off any visible dirt or give the spears a light washing with cold water before storing. It’s very important to dry washed spears thoroughly; moisture can lead to mold.
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.

Recommended Varieties

Asparagus plants are either male or female. Female plants produce berries; males 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, 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.

White asparagus

Wit & Wisdom

A pinch of baking soda in the cooking water keeps beans, spinach, and asparagus greener.
At only 40 calories per cup, asparagus is amazingly good for you! See our list of awesome asparagus health benefits.
For more planting tips, see our page on growing asparagus from seed.

Recipes

Cooking Notes

Watch our video on how to properly clean and trim asparagus.

A simple and easy favorite when it comes to asparagus is fresh roasted asparagus. Or try this simple, delicious asparagus soup.

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Reader Comments

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Gratitude for this site!

Suburban gardener, I planted 11 feet of Mary Washington, and same of Purple Passion (boring color when cooked) about 17 years ago. It makes me VERY happy!!! Just me to feed, so occasionally my neighbors get some. I was just wondering how long I must wait until I fold down the ferns, but you've given me the answer: I can CUT is short (I don;t know why my habit has been simply to fold it down) and use it for mulch after I put down the compost I have planned for it. (Thank you for THAT tidbit!) Problem with straw is that it never rots..... Many thanks. My initial information came from the Ag department of the U of TEXAS!!! Your outline and suggestions above are better presented and clearer.

Aspargus and weeds-weeds in aspargus?

What can I use to keep weeds out of the aspargus bed?

to minimize weeds . . .

Mulch. Or hand pick the weeds.

My Asparagus Question

I am so sorry for the multiple submissions. I didn't think my question was being "saved." Again, my apologies.

Little fern-like "things" growing near asparagus crowns

I'm wondering if these ferny growths (currently around 3-4 inches high) are new future asparagus plants and if I should allow them to continue growing. Perhaps they are just weeds. Some have emerged on the pathway side of the crowns, so I have removed those. However, some of these little fern-like "things" are growing two feet on the other side of the crowns. I have not removed those yet. I have thirteen crowns in their third year. This is our first year harvesting. We have been pleased with production so far and have enjoyed asparagus side dishes at meals for about 5 weeks. I'm thinking it might be time to stop harvesting. A few stalks got ahead of me and are already 4 feet high and getting the expected ferny foliage.

little ferns

They may be future stalks; let them be. You’re right; it is about time to stop picking. You could lay on some mulch and prepare to set stake poles and string around the bed (like a simple fence) so that when the ferns become top heavy they do not fall to the ground.

Asparagus

I have a wonderful asparagus bed that is 5-6 years old. I have little fern like things coming up around each crown. Separate and very different than the spears of asparagus. Are they weeds or part of the plants ?

tiny ferns

These are part of the plant.

Asparagus

I have a half dozen plants in my garden they are doing well and we were able to harvest some this is the third year. My issues is the ferns, they are so tall they fall over and cover the path and what is growing the next row over. Can I trim them back some?

falling ferns

You would do well to leave them. Set a long sticks or bamboo poles into the dirt on the corners and a couple/few on the sides. Run string around the poles and around the asparagus bed (not the plants) at about four feet high (or higher, there is no magic formula) to keep the ferns off the ground. This is not a fancy fence; this is a temporary (annual) sort of “framework” to support the ferns. They might lay over on the string and that’s ok. When you cut the ferns later in the year, put away the poles and string for next year.

salt

can you add salt to asparague bed to help

No Salt

No, that would not be beneficial to the asparagus—in fact, it would likely harm the plant.

Question from "R"

It is early. If you added that much material you added days to the emergence calendar. I bet you will see spears within 10 days.
That being said, IMO, the time to add compost to the bed is fall, not spring.

Added soil

The Asparagus bed I have has plants of 2 and 3 years of age. We had a decent harvest last year but I felt they needed more soil. So this spring around the 1st of April we added approximately 3 to 4 inches of soil mixed with compost and also added a heavy layer of straw. It is now the last day of April and I do not see any asparagus coming up. What could I have done wrong? and at this point what can I do to correct it? Thank you

Badly bowed/bent spear; new crowns and a novice gardener

I recently planted asparagus crowns for the first time. The first spear to come up from any of them was brutalized by wind and frost (and most likely my well-intentioned, but poorly executed insulating row cover). Now it's a pitiful bent thing. I tried to support it with twine and stakes (which I've heard are recommended later in the season for ferns anyway), but it looks like it is beyond hope.

Should I snap/cut it to encourage a new spear to come up - or just let it languish?

Thanks!

Bent Spear

As long as it isn’t entirely broken, it will still develop into a fully-fledged fern and be able to soak up the sunlight, which is the sole purpose of letting the spears develop. For now, just support it with stakes and twine as best as you can. The plant should send up more spears soon enough! If the bent one starts to look like it’s rotting, then you can remove it from the plant, cutting the spear off at the soil.

Bermuda Grass in Asparagus Bed

I just took over an old garden bed in Central Texas, and learned that the garden wasn't tended last year. The raised asparagus bed is clogged with Bermuda grass, and right now the asparagus spears are beginning to come up. Since Bermuda grass chokes most anything out, how can I eventually take out the Bermuda grass without destroying the asparagus?

Asparagus bed

We planted 20 plus roots last year in a proper prepared bed, had 3 shoots last year. Thinking this year more would appear but no luck. Can it take a couple years or more before we get more shoots or do we need to replant?

harvesting asparagus

how long can you harvest asparagus in a well established bed?

Year three

This is my third spring since I planted my asparagus and I only got three shoots. Every year they seem to get bigger and bigger and I leave them all summer, but they aren't multiplying. The plants reach over six feet tall and are a solid inch thick at the base. I planted the crowns three different places around the property to determine the best spot. All locations are the same only three or four shoots.

3yr asparagus stalks

I had the same thing happen but my understanding is that year 3 after planted from seed will be a sparse crop over s 2 wk period. Each future year the crop increases in volume as plants develop.

Dead asparagus

My 30 year old carefully maintained and productive asparagus did no t come up this year. The old crowns are just doing nothing underground. Scattered volunteer babies are growing well enough around the bed edges. But the fat spears from the original plants are just gone. Do these plants finally reach an age where they just die? The patch was planted at 2 separate times so there were a couple of varieties. They all died. Any ideas?

no spears

What a disappointment! Certainly 30 years is a good run, and by most estimates near the max, but it’s hard to believe that all of the crowns would fail from age all at the same time. The plants could be diseased, with fulsarium wilt or a rust. Cornell U is a reliable source of info on this; scroll or search this site for specifics re diseases: http://vegetablemdonline.ppath.cornell.edu/factsheets/AsparagusInfo.htm You could also inquire of Cornell’s Plant Diagnostic Clinic http://plantclinic.cornell.edu/contactus.html or consult the folks at the cooperative ext nearest you: https://www.almanac.com/content/cooperative-extension-services

asparagras

have you heard of salting your beds to control weeds ?and what do you think of this practice

save the salt

This has been a question for centuries. The belief a hundred years or so ago was that it improved production or, at least, controlled weeds. Today the thinking is that salt on an asparagus bed is not beneficial. It can form a crust that impedes was absorption and can actually harm the plants. Save the salt for the dinner table. And go lightly.

Asparagus

Why do they cover the asparagus fields with foil in europe?

foiled again

No idea. Where did you see or learn of this?

Transplanting Asparagus

I planted crowns this spring and now have new ferns about two feet tall. I planted the crowns about a foot apart in my raised bed and want to remove every other plant so remaining plants will have proper room to grow and I can share plants with my neighbor. How and when can I dig up the plants and transplant? Do I go through the winter with typical cutting back dead ferns and mulching then dig up entire plant in the spring to transplant?

fall growth of asparagus

We have cutback our asparagus and have warm temps still. I now have 12 inch tall growth in my plot. Do I wait till brown or should I keep it mowed?

Mow or not?

The rule of thumb is to cut back the ferns when they turn brown. If this is new growth, it may not get to the fern, then brown stage in the remaining few weeks of the season. Our best bet would be to wait until a hard frost then cut it back to about 6 inches.