image source: iStock.com
Unlike most vegetables, asparagus plants are perennial, which means the same plants grow in your garden year after year. The spears that we enjoy as a vegetable are the new shoots that emerge in spring. The most important part of growing asparagus is to realize that it will take a couple of seasons before you taste the first bite of homegrown asparagus. Plants need to be allowed to mature before you can harvest. They will remain in the same place in your garden for many years—15, 20, sometimes 30. In fact, a productive asparagus bed is a good reason to renovate your house, rather than move!
Asparagus grows well in all parts of the country except the warmest portions, zones 8b and higher. Because of the mild winters, plants do not go completely dormant. Plants cannot gain strength and will decline.
How much your family enjoys asparagus determines how many plants you will need. A good start is 10 plants for each person. If it is a family favorite or you plan to freeze some for later, you will need more.
Soil, Planting, and Care
Asparagus should be grown in a dedicated bed where it can come back year after year and where weed competition will be low. This bed is shown in late summer.
The key to growing asparagus is to have healthy, vigorous plants that produce a lot of spears. Choose a sunny, well-drained site on the edge of your garden where it will not be disturbed by the activity of planting and re-planting other areas.
Planting asparagus is like preparing for a trip. Careful preparation makes the journey easier. It is the same with asparagus. Before you buy the plants, you need a prepared bed. Hopefully this is the only time you’ll plant asparagus. How well you prepare the bed determines the vigor of your asparagus patch for years to come.
Space plants 12 to 18 inches apart. If there are tenacious weeds or grass, treat with an herbicide for use with food crops, or cover the area with black plastic during the summer before planting to eliminate problems in the future.
After the spring harvest, asparagus plants grow tall with beautiful fern-like foliage through summer. In early fall, they begin to die back.
In autumn, prepare the soil by placing at least 3 inches of organic matter on each row. Use organic matter such as composted manures, leaf mold, anything you can use to create a rich bed. Till it in. Have your soil tested and amend it with lime if the pH is below 6.0 to 6.5. Add any other nutrients as recommended on test results. Mulch for the winter, or grow a cool season cover crop that can be turned under before planting in spring.
In spring after danger of frost has passed, dig a depression 6 to 8 inches deep running the length of the row, mounding the amended soil on each side for later use. Set seedlings into lowest part of the depression, planting about 2 inches deeper than they were originally growing. Space plants 12 to 18 inches apart.
Feed plants with Bonnie Herb & Vegetable Plant Food at planting and twice a week through the summer as directed on the label. This will give plants the best growth possible during their first season.
As plants grow taller, rake a little of the soil on the edge of the row into the depression where plants are growing. Soon the bed will be level. Mulch to prevent weeds.
Then all you need to do is be patient. The ideal is to wait at least 2 seasons and probably 3 before harvesting. It may be hard to resist tasting the first spears to emerge, but go easy on the plants until they mature. You’ll be rewarded in the long run!
Asparagus is dioecious, meaning it has male and female plants. Female plants produce seeds—the little red berries shown here—that can reduce the yield of the plant, as energy is put into seed production instead of back into the root system.
Bent spears are caused by insects feeding or damage from cutting adjacent stalks. The damaged stalk grows normally on the side away from the wound, causing the spear to bend.
A well-drained bed will have minimal disease problems. Black and red asparagus beetles can be a challenge, damaging the foliage and weakening the roots. Usually you can control them with hand picking. Just drop them into a bucket of soapy water.
Harvest and Storage
The new shoots of these asparagus stalks have already been harvested. See how they’ve been cut or snapped close to the soil line.
Once asparagus plants are strong enough to be harvested, cut all new shoots in spring when they are about 8 inches tall, snapping them off at the soil line. Many seasoned gardeners use a knife to cut below the soil line, but it is important to avoid cutting into emerging spears nearby. Also, the knife can spread any disease from one plant to the next.
Remember, if the spear has begun opening and developing foliage, it will be too tough to eat. To avoid this happening, plan to harvest at least every other day. Go ahead and pick all the spears each time you harvest. Discard those that have grown too large.
The duration of your harvest will depend on the vigor of your plants. If your plants are young, the fresh asparagus season may last a couple of weeks. However, established plants can produce much longer, as much as 8 weeks. The old rule of thumb is to harvest until the diameter of the spear decreases to the size of a pencil. Then it is time to stop and let them grow, gaining strength for next spring.
Cook cut spears immediately or refrigerate in plastic to raise the humidity and prevent tough fibers from forming at the base of the spear. These fibers form as a result of the injury of cutting. That’s why spears from the grocery store or from the refrigerator should always be trimmed to remove any tough tissue before cooking.
Fresh asparagus spears can be stored a week or more. If you want to put some aside to enjoy in the months to come, blanch them in boiling water for 3 to 5 minutes, douse in cold water, wrap, and freeze.
Cut back the 4 to 6 foot tall foliage, or the ferns as they are called, after frost has turned them brown. This is a good time to control weeds because the asparagus are dormant. Keeping the bed weed free is important to avoid competition with your asparagus plants. Because the soil is so rich, invaders can take hold quickly.
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Love all this good advice on starting asparagus…..a new experience for me. Being 80 yrs of age, I don’t have time to botch this up! I’m concerned about separating the little seedlings safely to be able to plant them individually in little peat pots. The Bonnie plants I purchased are only 3″ to 4″ tall and very frail. I live in zone “5 and plan to put them in the ground in a couple of weeks.
Water the aspargus well before gently teasing apart to replant. When the soil is wet, it is a lot easier. If you do not want to transplant them now into individual peat pots, you can wait and do it at planting time. Good Luck, let us know how it grows! -danielle, Bonnie Plants
This year my asparagus came in late and many of the spears were really thin. They got fatter as time went on, but I noticed many thin young ferns coming in like never before. I have many male plants and a few female plants. Are the females suddenly causing a problem after 15 years? Also, my plants are planted in gopher wire, which has worked for years, but now the gophers are digging around them like crazy. Any answers to this problem? Thanks ahead of time. Nora
Sounds like your aspargus patch may have become overcrowded over the years. You can thin the asparagus – and even share the wealth! Females do cause a small problem when the berries drop. Try to weed and clean the patch as much as you can – which means the seedlings produced by the berries. Hungry gophers, exclusion is the best way – which you are already doing. Fencing should be buried a bit into the ground, if they are no trying to dig under, try the buried spikes which can help deter them. Here are more recommedations from Utah’s state extension system. -danielle, Bonnie Plants
Hi. I’m new to all of this! My mother in law has been growing asparagus for 30+ years. We dug up a pretty large patch to plant into mine and my husbands new garden! Very exciting until I was told that I’m not allowed to eat the asparagus for a few years. However, is this still the case since the asparagus plant is older? I’ve got 15 or more stalks that are pretty large. Thanks!!
If you dug up and moved established crowns (didn’t dig and divide), you could harvest a few this year. Just leave most of the spears to fern so the plant will send its energy into establishment. Harvest away next year! – Danielle, Bonnie Plants
have 5 plants that are all ferns in may there very skinny been planted over 5 yrs advice. made bed followed all directions how do I fertalize them better
Hi Mrs. Duncan,
Keep the asparagus bed as free from weeds (that will compete with the asparagus) as you can. Once weeds are clear, use and organic mulch to help with soil moisture and and weeds that try to make a come back. If you have not aready, have your soil tested and amend it with lime if the pH is below 6.0 to 6.5. If you do have a soil test of the garden area tested, it will give you fertilizer recommendations based on the results. Harvest the asparagus daily during harvest period – you will get the spears before they start to put on their foliage. -danielle, Bonnie Plants
I planted three years ago, let fern the first two, and have many harvestable spears right now all around the original planting spot. Yeah! However I am also seeing a lot of very small ferns. some 12 inches or more away from an original root site. Are these new plants? i have no idea how asparagus spreads. Should I leave them or weed them. Most are small, and less than 12 inches tall. Thanks for you help
Do you have female asparagus plants or male asparagus plants? If you have female asparagus plants, you will notice berries on the ferns that may drop rom the plants – small seedlings may come up. I would remove any new seedlings – they are usually inferior to the parent. -danielle, Bonnie Plants
Thank you. We do have a few females and have thought about replacing them with males. We want to expand the bed next year. Should I dig up the families and replace for an all male bed. Are they needed for any reason? Or is all male better.
You could just expand with a male variety if that is what you wanted to do. It may hurt your feelings to dig up an established bed. You do not have to have male and female varieties 🙂 – danielle, Bonnie Plants
Last year we ordered and planted what were supposed to be all male Jersey crowns. They flourished unharvested and this spring we have had a very small harvest. When you say harvest for 3-4 weeks…do you mean harvest all the spears that come up, or pick and choose. I am afraid to harvest too many that I might damage or weaken theplants. Now I notice my carefully weeded asparagus bed is full of asparagus seedlings. Can I assume I did not get all male plants? Should I wait until fall and remove the ones that have berries? Can I transplant the seedlings? Can I assume that because the parents are bred to be wilt resistant the babies will be the same and the same variety? Are deer fond of asparagus?
Lots of questions. Thanks
I usually harvest about 75 percent of the spears for 3 – 4 weeks. By the 4th year, harvest lasts 6 weeks and longer in some areas. If you did see berries on the the asparagus plants, you do have some female plants. If you have both male and female plants, you can remove the female plants if you would like; the seedlings from the hybrid variety are usually inferior to the parents and may/may not have all the characteristics of the parent. Deer have been known to munch on the foliage 🙂 -Danielle, Bonnie Plants
Since I was the youngest of 5 kids it was my job to cut the asparagus just before dinner. We lived in upstate NY and had a very prolific asparagus bed. However that was not always the case. What made it really great, in my opinion, were 2 major factors. In 1952 my mother bought a small Planet Jr. rototiller. As soon as we could in the spring we would rototill the entire 20 ft. sq. area. Then apply 50 lbs. of rock salt. As a result not one weed would emerge. Only the perfectly healthy spears. I realize you can’t recommend this but for people who want an organic method for weed control. Here it is. Try a test spot. Thanks.
I have some asparagus plants that I bought last year and never got around to planting. I have kept them in the bottom drawer of my refrigerator since then. Do you think I will be able to plant them now; will they make it?
Odds are not in your favor….but it doesn’t hurt to try 🙂 -danielle, Bonnie Plants
We planted about 60 plants in 2008. So far we have had hardly any growth. Any suggestions?
How well was the bed established? That is really a key part of growing asparagus. Allow 12 – 18 inches between plants (in fll sun) for healthy growth – filling in around the plants with compost. Have you been harvesting the spears? Patience is also a virtue – limit any harvest the first year to allow the spears to fern out – this gives the plant energy for the following year. The second year, harvest for about 2 weeks, leaving the rest of the spears again. By the 3rd or 4th year, harvest usually lasts about 6 – 8 weeks. Have you fertilized or checked the pH of the soil? Have your soil tested and amend it with lime if the pH is below 6.0 to 6.5. You can buy a home soil testing kit or have one done at your local extension system. -Danielle, Bonnie Plants
Some asparagus is coming individually, some are as large as my thumb. Should i cut them or leave them to help grow other spears. I believe that the rest of the spears are fed by the one that comes up first or am i mistaken?.
Harvesting depends on the age of your asparagus plants. When the plant is young, you may only harvest for a couple of weeks, letting the rest of the spindly spears go on to make foliage – gaining strength for the next Spring. As your plant matures, harvest may last as long as 6 – 8 weeks. You can read all the details on when and how to harvest your asparagus, here, under the harvest and storage tab. – Danielle, Bonnie Plants
But if just one spear is coming up,even though as big as my thumb, should i harvest it or let it go to fern stage for more later?
If you only have one spear come up, you will want to let it fern out. – danielle, Bonnie Plants
I would like to add some fertilizer to my asparagus bed but need some information as to what I should add. Would lime pellets work or not?
Lime pellets will work – if you need them 🙂 Lime raises the pH. Have your soil tested and amend it with lime if the pH is below 6.0 to 6.5. You can buy a home soil testing kit or have one done at your local extension system. Asparagus thrives in organic matter, so be sure and add a couple of inches of compost, rotted leaves, or other organic matter to keep weeds at bay and the asparagus happy. – Danielle, Bonnie Plants
Could someone please tell me how much water does asparagus need? And I already fertli. when March came and I uncovered them from the straw I had around them. Now do I do another fertli. say, like now? I use Dr. Earth Organic fertil. and make a tea. Would that be ok. Appreciate and help/advice
Most garden vegetables need an average of an inch of water per week. These water needs can double if you live in the hot temperatures especially on soils that dry out quickly. This should give you ideas on getting the water to your plants when rain is not cooperating. You may need to fertilize several times during the growing season is if you are using a low analysis water soluble fertilizer. – Danielle, Bonnie Plants
My two years plants are prolifically producing this spring – however, they are immediately ferning out. Do you know how to fix this problem? Thanks.
Harvest the spears early – before they start to ‘fern out’. Plan on harvesting at least every other day to stay ahead of the foliage. – Danielle, Bonnie Plants
Are any portions of the asparagas plant poisonous to animals? Thinking of planting along fenceline and wanted to make sure.
The berries of the female asparagus plants are considered toxic and may cause stomach nausea if ingested. -Danielle, Bonnie Plants
I have not seen any spears
– it seems they come up and immediately fern out.
If the spears are coming up and ferning out while the spears are very small, your asparagus may not be mature enough for a long harvest. You said this is the second year they have been planted? This is usually the first year asparagus should be harvested, for a short time (about 2 weeks) and the rest of the spears are left for foliage. By year 3, harvest lasts about 4 – 6 weeks, and by year 4, harvest is about 6 – 8 weeks. Be sure and fertilize and take care of any weed problems in the asparagus bed to produce healthy spears! – Danielle, Bonnie Plants
I have asparagus plants that are just into their second season and reaching over 7 feet tall. Some are actually falling over. Can I cut these back a bit without harm to prevent the stalks falling?
It’s a good idea to let the asparagus foliage do their thing. This foliage provides the energy for the crop the following spring. When fall / winter frosts come and kill back the foliage, snip it off at the ground. – Danielle, Bonnie Plants
I, too, have had trouble with my tall stalks falling over. Last year was year 2 for us, and it seemed that every time we had a heavy rain or wind storm, our asparagus was all toppled over. Do you recommend staking it in some way once it is tall and fern-like? Our bed is inside our garden and the leaning and fallen stalks get in the way of our paths and other beds.
The wispy foliage of asparagus does seem to catch the wind. I really like the ‘uncontrolled’ look of the ferny foliage. If it causing you concern, you could try a couple of stakes at either end with a string between to help keep the foliage straight and in check. – danielle, Bonnie Plants
Just got my asparagus roots in the mail, can I plant them in a pot untill I get my garden worked up? Should I keep these in the carport or out side?
I am not sure of your area, but sometimes roots are shipped so they can be held a couple of days before planting. If this is so, I would get the soil ready ASAP and plant them directly.
-Danielle, Bonnie Plants
I live in south mississippi,I put the plants in pots in that a good idea? or would it be better in the ground.
Asparagus plants are better off planted in the ground…they will spread and become large plants. – Danielle, Bonnie Plants
My asparagus bed is around 23 years old. Our soil is a ph of 7. We usually put compost on the bed and sometimes some wood ashes. I live in Texas – Zone 8. This is the first year it is producing very little, and the spears are mostly female plants (I think), but there are some males that are not as big as usual. We have been picking it for about 3 weeks. Should we not pick anymore and let all the spears grow up this season, or is it time to replant?
Twenty three years is awesome! A well tended bed lasts anywhere from 20 – 30 years. You may consider replanting soon. Soil pH is high but not terribly high so be careful with the woodashes – pH will rise quickly. I would harvest as usual and think about starting another bed.
-Danielle, Bonnie Plants
Can you chop up the feather portion of the plant and put it in salad greens? Is it edible?
Sounds good, not so sure how that would taste 🙁 Parts of the foliage contain poisonous compounds and the berries should never be consumed!
-Danielle, Bonnie Plants
My father eats the whispy, feather-like portion in moderation, but never the berries because they will cause you to become sick. He thinks that the fern tips taste like the young asparagus.
cool! i love asparagus!
-Danielle, Bonnie Plants
I have read all your comments on growing and caring for asparagus and saw nothing about SALT. I have applied salt to my bed for years and it kills weeds and grass and the asparagus thrives on it. Common table salt or rock salt- whatever it all works.
Since there is not a pesticide label for salt, we can not recommend it.
-Danielle, Bonnie Plants
I think epsom salt is good for plants, not so much because it is a salt, but because of the magnesium in it. I would be careful about putting too much salt in your soil.
Answer to the black asparagus beetles; inter plant with petunias and keep the bed clean. It worked for me in zone 6b
I have greenhouse in zone 9 but want to grow asparagus as one of my favorites! Any suggestions?
This article is our best, most comprehensive tool on getting started with asparagus. Make sure you choose a site that you’ll dedicate to asparagus for years and years to come. Mulching is very important, too, as it’s a perennial crop and you won’t want to weed it constantly. Gardeners in really warm climates aren’t as successful as those in more temperature climates (Zone 7 and north), but reports show that it can be done. Take care to choose a northern-facing site or choose a spot with shaded afternoons when it’s hottest. Choose a variety that your local Cooperative Extension office has tested for hotter climates, too.
Mary Beth, Bonnie Plants
Hey Kelly & Mary Beth,
I want to grow asparagus, but after reading your helpful information, don’t think I can. I have a raised garden bed, but I want to plant other veggies in there. I do not have any space to put a bed dedicated to asparagus. Could I grow it in a pot and let it mature in there?
I think you’ll want to dedicate space — permanently — for the asparagus to spread and increase in production. A small pot won’t produce asparagus in much quantity. If you have 2 years and at least a 4×4 space, then add it to your garden plan!
Mary Beth, Bonnie Plants
I bought some asparagus plants, my question is do i plant the tassles up or down?
Have you gone through the step-by-step planting instructions above? Be sure to read all of the tabs, too, that describe Troubleshooting and Harvesting info. You will plant the crowns with roots going down into the soil and the green “fuzzy” tops (if that is what you mean by tassles) are above the soil. Give this a detailed look and let us know if you have any further questions. It’s one of the best edible investments you can make in your garden for years to come!
Mary Beth, Bonnie Plants
I have a small asparagus bed now in its 3rd year. We live in the Basque country, Spain, where the climate is more Continental than Mediterranean.
There are tall green ferns still, almost December.
Do I cut them back, leave them or what?
Many thanks in anticipation
Lucky you! Basque country is beautiful. The ferny fronds are gathering much-needed energy and storing in the roots for the next season. Don’t cut them until they turn brown. If you click the tab in this article for further information on Harvesting, Storing, and Troubleshooting, you’ll find more details on step-by-step care, such as this: “Cut back the 4 to 6 foot tall foliage, or the ferns as they are called, after frost has turned them brown. This is a good time to control weeds because the asparagus are dormant. Keeping the bed weed free is important to avoid competition with your asparagus plants. Because the soil is so rich, invaders can take hold quickly.” Happy growing and happy holidays!
Mary Beth, Bonnie Plants
I have approximately 12 asparagus plants that I just planted early spring. What should I do to prep them for winter. I understand about providing a good mulch on top of the plants. Do I cut the plants back. Not quite sure what to do
Sure, we can help. You might have missed it in the “Harvest and Storage” tab, but click there for more detail. Your plants will need to stay intact for a while after growing into frothy fronds, as they are providing energy to the roots. You’ll want as much energy to go to these roots for double the harvest and production next year. After a hard freeze, they’ll turn brown and you can cut them down to the soil level. Keep it heavily mulched, as asparagus hates competition from weeds. Happy growing. Check out our Facebook page and join the weekly fun and gardening help there, too.
Mary Beth, Bonnie Plants
I bought a 6-pak of your asparagus at a local national merchant here, in zone 9, in late August. I am planting them in an isolated 4′ diameter hill. Following your planting instructions, will they survive/thrive in Arizona, given proper fertilization, water and attention? Should I break up each of the individual six plantings?
Thanks for your help,
The only trick to growing asparagus in warmer climates is that the mild winters won’t allow the plants to go completely dormant. Plants cannot gain strength and will decline. Above, we specify these areas as zone 8b or higher. Do you know your zone. Depending on where you are in Arizona, you may be fine. Also, yes, you should separate the individual asparagus seedlings and plant them separately. Our pots are sown thickly, so you get more plants for your money. Happy growing!
Kelly, Bonnie Plants
In this post you say “Above, we specify these areas as zone 8b or higher.”, I would think that it should read zone 8b or lower as the higher count above say 9 has less of a chance for the cold that you say it needs. So which is it I am in El Paso Texas in zone 8a. I appreciate you taking time to clear this up. Jim C.
I think what Kelly was sharing with the Arizona gardener is that asparagus is less successful in zones where it is warmer and no chance for the plants to go dormant in winter–zones 8b or higher (zones 9, 10, etc). I think confusion happens with zones sometimes that those areas are usually geographically lower, or south. On the map, it’s “lower” physically but the higher number of the zone, the milder the winter and lesser number of freezing days. Also, the zone map was altered by USDA this year for a few areas, so check to see if your region was updated. 8a is great for asparagus, so get to planting!
Mary Beth, Bonnie Plants
I bought two Bonnie plants Asparagus plants… in biodegradable planters…. do I need to thin these and spread them out. if so, when. or, do they grow well in that tiny space together. also, how many should I have? we’re a family of 6 right now and we love to entertain. Do you know roughly how many seeds come in those Bonnie planters.
Our asparagus plants in biodegradable pots do come seeded rather thickly. It wouldn’t hurt to separate the plants, which you should do when planting. You can carefully separate the seedlings and plant them individually. If planted all together, they will grow but be tight for space. You can thin them out as you would if planting from seed. It will require about 20 or so crowns and several years of growing to produce enough to feed a large family. I hope this helps!
Kelly, Bonnie Plants
I have an asparagus bed that has been on my property for many years. The problem I have is the crab grass and weeds have started to take over. Does anyone have any ideas on how to get rid of the weeds without damaging my asparagus plants?
How bad are the weeds? Can you carefully hand-pull a few weeds this growing season until the asparagus plants die back for winter? In the Harvest and Storage tab above, we recommend that you weed the beds after frost, when the asparagus ferns have been cut back and the plants gone dormant. This way, you won’t disturb your precious asparagus.
Kelly, Bonnie Plants
I find it easiest to give the bed a good gentle soaking. The pull away! The water will loosen the roots and allow them to come up MUCH easier than dry soil. Just be careful to pull out weeds and not asparagus! You don’t want to use herbicides, and those weeds will just keep at it if you don’t take care of them before they go to seed.
This year l am seeing small flying insects on my asparagus plants and with that small black dots on the stalks. Any idea what this is and what l can do to rid this vermin from my beloved bed of asparagus ?
I got this answer from our Ask an Expert service. (Next time you have a problem, you can send your question directly to this link .)
Asparagus beetles are the most common pests of asparagus in North America. Read this article on them and their control. Does this look like what you saw or the damage on your plants?
I hope this helps!
Kelly, Bonnie Plants
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