Growing Asparagus

Planting, Growing, and Harvesting Asparagus

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Asparagus is one of the first plants that greets us in springtime. It’s a perennial, which means that once it gets established, asparagus will return year after year. Early spring is the time to plant asparagus, so what are you waiting for?

Note: Asparagus plants may take 2 to 3 years to truly get started and produce, so patience is needed! But then again, the plant can be productive for 20 years or more, producing ½ pound of spears per foot of row in spring and early summer, so we think it’s worth the wait.

Asparagus are dioecious, which means that there are male and female plants. The key to the sex of the plant appears in the fall: Red berries form on female ferns. Inside the berries are tiny seeds—about 19,200 to a pound—and, yes, you can plant them—although it will take at least 3 years before you have a harvestable crop. Because male plants do not need to expend energy in producing berries, they have stronger root systems and can be up to three times more productive than female plants.

Regions with cool winters are best for this cool-season crop, which is planted in early spring.

Planting

Preparing for Planting

Asparagus is planted in early spring as soon as the soil can be worked.
The plant is normally grown from “crowns” (1-year-old plants).
Before you do anything, check the pH of your soil. Asparagus likes a pH of 6.0 to 8.0.
Asparagus does not like to have its feet “wet,” so be sure that your garden bed has good drainage. (For that reason, raised beds can be a good place to plant asparagus. Learn how to make a raised garden bed.)
Eliminate all weeds from the bed, digging it over and working in a 2- to 4-inch layer of compost, manure or soil mix. (Learn more about soil amendments and preparing soil for planting.)

How to Plant Asparagus

Plant crowns deeply to protect them from the deep 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.
Within the trench, space asparagus crowns 12 to 18 inches apart (measured from root tip to root tip).
The traditional method of planting asparagus goes as follows:
1. Add a 2-inch-high mound of rich soil to the bottom of the trench and place the asparagus crowns on top of the mound, spreading their roots out evenly.
2. Add about 2 inches of soil over top of the crowns.
3. As the season progresses and spears grow to be 2–3 inches tall, add 2 more inches of soil, being careful not to bury the spears completely.
4. 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 one or two more times throughout the season.
5. After you’ve filled the trench completely, mound the soil slightly to prevent water from pooling around the emerging spears.
Rather than fill in the trench little by little, some gardeners prefer to fill it in 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:

Care

How to Grow Asparagus

When the trench is filled, add a 4- to 6-inch layer of mulch and water regularly.
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 in spring and early fall and cutting down dead foliage in late fall.
During the third year, the bed should be in full production, so you can start to harvest asparagus sparingly throughout the season.

Pests/Diseases

Asparagus beetles
Cutworms
Slugs
Crown rot
Rust
Asparagus is considered a deer-resistant plant, so plant it near more susceptible crops.

Harvest/Storage

How to Harvest Asparagus

If you have young plants, the season may last 2 to 3 weeks. However, established plants produce longer—up to 8 weeks.
Asparagus can take three growing seasons to harvest, though you may be able to lightly harvest during the second year.
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 at 6 to 8 inches tall and at least ½ inch thick, cutting the spears off with a knife or scissors at the soil line.
Stop harvesting spears when the diameter of the spears decreases to the size of a pencil.
After harvest, allow the ferns to grow; this replenishes the nutrients for next year’s spear production. Always leave one or two spears.
Cut back asparagus AFTER the foliage has died back and turned brown or yellow. This is usually in the fall after frost. Cut back to the ground.

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

For highest yields, plant male hybrids such as ‘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.
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.

White 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.

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

A simple and easy favorite when it comes to asparagus is fresh roasted asparagus.

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Reader Comments

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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.

asparagus

My asparagus bed is 15 yrs. old. Because of excessive rainfall this year, a vine has grown on my asparagus ferns. The ferns are browning in early September before frost. Will this harm my asparagus plants?

brown asparagus...

Asparagus is vulnerable to a number of diseases, including rust, fulsarium wilt, and stem/crown rot. It is difficult to know which your plants might have, but excessive rainfall (or watering) on soil that does not drain well is one of the causes. At the risk of too much information, this link provide pics and info on what seems like the full panoply of possibilities, with some advice: https://www.limgroup.eu/applications/limgroup-productsite/assets/books/e... (Note: it is a European source) If you can identify your problem, you may be able to consult a local nursery for guidance.

plant info

dont have any info about once harvested ow to store it

Storing Asparagus

We have updated the page to include info on storing asparagus. Please see above!

asparagus

Didn't wait for the fronds to turn brown will this affect next year's harvest?

No growth, year 2

I planted 10 roots last spring and left them grow through the fall and then cut them back . They looked great. This spring, I see no growth from any of the plants. Should I replant or just be patient and see if they come up next yeat ?

No sign of spears yet

This is a tough one. Did you properly prepare the trenches: check the soil pH, add in a heaping helping of compost and aged manure? Are the trenches getting enough water (hand or sky delivered)? If you mulched them for the winter, have you tried moving some mulch to see if any spears are poking up? You do not say where you are; if you’re in the north country, this might be normal. (Are you seeing it growing anywhere else in your area?) It would be a shame to start all over again. Before you do anything, contact your local cooperative extension and see what they have to say about it. Being in your area they know better what you can expect/need to do. Choose your state here and contact the one nearest/for you: https://www.almanac.com/content/cooperative-extension-services

Thanks

Thanks for the suggestion, I will contact my local extension office. I am located in Minnesota and yes, I did prepare the soil properly but have not checked the pH. Will also do that.

Maintaining Asparagus soil

My asparagus plants are into their 4th year and looking ok. They are fertilized regularly and weeds kept clear of the rows. I know the soil is not the best, so I am wondering if during the fall after the ferns die I could till in some sandy loam in the rows, say 3-4 inches deep.

fall care

Asparagus is fairly tolerant to a variety of soils, but does like sandy loam. If your plants look healthy, it might not be necessary to add the loam. If you do decide to try it, however, you might set the depth at 2 to 3 inches instead, to be sure not to damage any shallow roots. Or, if you have a small enough bed, gently work the loam in at that depth with a rake or shovel. As you have indicated, the plants should be dormant when you do this. Some gardeners instead add aged manure or compost in fall, along with a layer of mulch, which will gradually improve the soil structure and health. Others might work in soil amendments in early spring, before the spears appear.

Asparagus

We planted asparagus crowns last year. This year I noticed a rabbit had eaten one of the spears, so to protect them I put a hoop frame over the bed. The spears are now about 24" long, and branching out. Do I just leave them or should I be doing something with them?

asparagus care

As they are still too young for a full harvest, and it is past harvesting stage (when spears are about 8 inches tall, and not branching), then you should, as you have suggested, just leave them to grow. Eventually they will grow tall with ferny leaf growth–too tall for the hoop frame, but at that point, perhaps the rabbits won’t be as interested in the plants. Wait until fall, after the foliage has died and browned, before cutting the ferns down to about 2 inches above the ground before winter. The leaves will help the plant make food for itself to survive over winter and grow healthy spears next year.

asparagus spears/ferns/foliage

My asparagus is in its third year this year, should I cut off last years spears/ferns? They are about 8 inches high and fallen over due to winter

cut the ferns?

If you cut down the plants’ ferns last fall, leave those that appear now. You should be seeing some spears any time now, too.

Thin Asparagus and weeds

My asparagus bed is four years old and I am having a problem with some of the spears being way too thin to harvest. Also, can't keep weeds from taking over bed. Heavy running rooted weeds,crabgrass? Any advice?

weeds in the bed

See the advice immediately below re fertilizer, pH, and compost to increase the size of the spears (for that matter, read the advice we give above, too).

As for the weeds, you need to pull out as many as you can and then mulch. Several inches is not too much. And “edge” the bed: Push a spade or edge into the edge of the bed to cut the weed roots there. (You’ll need to do this every year.)

Old asparagus bed

I have a big asparagus bed that is over 30 years old. It still produces lots of ferns, but most of the spears are pencil-thick, and some roots seem to have died off. Every year I spread on a thick layer of compost/ seaweed. All I've read says that asparagus beds last for many years (this site says 20 or more), but none suggest what to do with an old bed. Do I dig out the old roots and start again? Leave a few plants and till deeply all around them? Abandon the site? No article has told me.

old asparagus bed

Some people would love to get pencil-thin spears!

Have you checked the pH? Asparagus likes lime. Everything you’re doing sounds good…so it might be the pH (you can get an inexpensive kit at a nursery). Digging out the roots would be a lot more work than you might think; roots could be 4 to 6 feet or more!

Then there is this (a few questions below yours): you might want to fertilize: Scatter 2 pounds of 10-20-10 fertilizer (or its equivalent) per 20 feet of row before growth begins in the spring. After the last harvest, apply an additional 1 to 2 pounds of 21-0-0 (high in nitrogen) per 20 feet. Always water the fertilizer into the soil.

With this, your plot should come back to life.

old asparagus bed

Bought a ranch once with a huge asparagus bed. Previous owner forgot to tell me. No defined rows, very old. It was late October and the whole area looked like dead weeds. So I started to pull them. They didn't budge. Got heavy gloves. No luck. Finally got a shovel and dug roots all day. It was impossible to get it all. Finally gave up. After the snow melted and I had long since forgotten those weeds, I was stunned by the prolific production of fat asparagus. I don't think thinning an old bed and loosening the soil could possibly hurt. Lived there a decade, it always produced plentifully.

My only complaint about growing asparagus is that I couldn't manage to get much in the house. I ate it all raw as I picked it. Had the same problem with the peas and of course the strawberries.

Beginner at growing asparagus

We just bought a home which has a raised bed of asparagus. Right now there are dried stalks about 3-4 inches sticking out of the ground and the bed is covered with dried leaves. What am I supposed to do with this? I’m not sure if I should remove the leaves or just let it be. Thank you

Asparagus beginner

I have had asparagus beds for decades and always pull out the 3" dried stems once the ground thaws. They *could* stay, but get in the way when harvesting new spears. Asparagus hates competition, so a thick mulch of leaves is good, but loosen up any areas where the leaves are thickly packed and might bend over the new shoots. I put piles of sandy seaweed on top each fall and find the top layer can get hard and crusty by spring, interfering with the new growth. But it's easy to pull the crusty layer aside and the rest of the seaweed is well-rotted and mushy so the asparagus can get through.