Growing asparagus from seed is easy, and it’ll save you a lot of money compared to buying pricey asparagus crowns. Whether you’re saving seed from heirloom asparagus plants, or simply purchasing asparagus seed, it’s easy enough to establish a whole field of asparagus plants for just a few dollars.
Growing Asparagus from seed often starts with harvesting seed from last year’s plants. Female plants produce red “berries” full of tiny black asparagus seeds.
These days most people plant asparagus crowns or first-year bare-root plants. Starting from crowns gives you a head start on production, and you’ll be able to harvest your first asparagus spears one season earlier. But that year of growth comes at a hefty price…
Nurseries sell asparagus crowns for as much as $5 each. A potted asparagus plant will set you back $10 to $12 in the spring.
A single seed packet, on the other hand, costs about $3 for a pack of 50 to 100 seeds. That’s a tiny investment for a whole field of homegrown asparagus.
Asparagus is a flowering plant that produces seeds, just like any other garden crop. For many years I believed that Asparagus was a fern, and could only be propagated by division.
I had never seen Asparagus “go to seed” because the asparagus crowns purchased from garden centers are all males. The female asparagus plants don’t produce nearly as many edible shoots, and instead, devote their energy to making seed.
Like so many of our food crops, asparagus flowers are bee-pollinated. Male and female plants are separate, and a bee must first visit a male asparagus flower on a male plant followed by a female flower on a female plant.
Since asparagus crowns are generally sold as male-only, you’ll only ever see the bright red asparagus fruits (seed pods) if you grow asparagus from seed.
Or, in my case, get a batch of asparagus crowns that happen to contain several female plants. Something went wrong in the selection process, and roughly 1/3 of the asparagus crowns I ordered were female.
The female plants are usually culled out because they produce far fewer harvestable spears. With 1/3 of my asparagus beds planted with female plants, the harvests are pretty slim each spring. But a ready source of female plants means that I have plenty of asparagus seed to plant each year.
When you grow asparagus from seed, you’ll have a choice. Either keep the female plants or cull them out to make room for more productive male plants.
As a home grower, culling out the female plants will result in a better harvest, but then you won’t be able to save asparagus seed. You also won’t get to enjoy the beautiful bright red asparagus fruit in the fall.
(If you’re not saving seeds or keeping female plants, you can always buy asparagus seed here. It’s rather inexpensive, especially compared to crowns.)
Saving Asparagus Seed
The seeds start out as dense clusters of round green seedpods. They’ll take months to ripen to a full dark red color. While at first, it may look like a huge harvest of asparagus seed, don’t count your eggs before their hatched.
Many of those green asparagus seed pods will be knocked off by wind or rain or picked off early by birds, long before they ripen.
In that time, a dense crop of asparagus seed will be reduced to no more than a small handful of ripe asparagus seeds per plant. That handful of asparagus seed pods still yields quite a few plantable seeds.
Each asparagus fruit contains several seeds, and a single female asparagus plant can produce hundreds of seeds in a good year, even accounting for losses.
Leaving just one or two female asparagus plants in your patch is often enough to ensure a lifetime supply of seed, provided those female plants survive and thrive.
When growing asparagus from seed, if you don’t cull out the female asparagus plants, they’ll be roughly 1/2 of your total plants. Allow the plants to mature for a few years until you can identify the female plants. At that point, I’d suggest culling down to half a dozen female plants at most.
To save asparagus seeds, harvest the berries when once they’ve turned bright red in the fall. Here in Vermont (zone 4), that happens in mid to late September. Allow the berries to dry for a week or two, and then carefully break the seed pods open and extract the seeds.
Lay the seeds out to dry for at least another week before storing them to plant the following spring.
This fall I harvested about 3 cups of asparagus seed from three female plants. Enough for hundreds, if not thousands of seedlings next year.
Growing Asparagus from Seed
Planting asparagus seeds is a simple process, and it doesn’t matter whether you’ve saved your own seed, or purchased a package of asparagus seed.
Start the seeds indoors 10 to 12 weeks before the last expected frost date in your area. In my cold Vermont climate, the last frost happens the first week of June. That means I’ll need to plant asparagus seed in mid to late March.
Most locations see spring a good bit earlier than we do here, and asparagus seeds can be started sometime in February.
Plant asparagus seeds about 1/2 an inch deep in fertile potting soil.
The seeds need soil temperatures between 70 and 85 degrees F for good germination, so it’s a good idea to invest in a seedling heat mat.
Since most garden crops only need to be started 6 to 8 weeks early, you can reuse the heat mat for tomatoes and peppers later on once the asparagus has germinated.
In the best of conditions, Asparagus takes between 2 and 4 weeks to germinate. Some seeds can take as much as 8 weeks to germinate.
That’s one reason why the seeds need to be started so early in the spring. Pre-soaking the seeds in lukewarm water for a few hours before planting can help speed germination, but it’s not strictly necessary.
Transplanting Asparagus Seedlings
Unlike asparagus crowns, which have a large root mass, asparagus seedlings are just getting established. Take extra care in handling them, and avoid damaging their roots. Plant them a bit denser than you would crown to allow for some dieback.
Transplant asparagus seedlings to the garden after the risk of the last frost has passed in your area. That’s the same time you set out tomato plants.
Crowns are planted 18 to 24 inches apart, but try spacing seedlings about 6 inches apart in rows 18 inches apart. If all the plants thrive, the extra crowns can be thinned out or transplanted later.
How Long Until Harvest?
When you plant asparagus from seed, you’re one year behind schedule compared with planting asparagus crowns. Crown planted asparagus can be harvested carefully in the 2nd year and fully in the third year.
For seed planted asparagus, harvest just a few spears in the third year and then you’ll be able to harvest a full crop in the 4th year.
In the meantime, just carefully tend the asparagus spears, keeping the beds free of weeds. In a few years, they’ll fill out the beds and give you a good crop in the spring as well as showy foliage in the fall.
Lisa
I love your blog and tips!
Sara White
I am currently growing asparagus from seed. I have 2-3 seedlings in each pot that are about 5 inches tall. Do I need to remove or trim some of the seedlings so that I only have 1 per pot, or can I let a few grow together in the same pot?
Ashley Adamant
I divide them when I transplant in the spring. If you have way more than you need, you can thin them to a single plant per pot, but dividing them at planting works well enough for me. If you’re going to keep them in pots past the spring and raise them in pots for a full year for any reason though, thin them to 1 plant or divide them and then re-pot them.
Amanda Reuter
If I want to leave them in a pot for the first year and plant them in the second year how large/deep should the pot be?
Administrator
You will want them to be at least a gallon or bigger.
Gloria
I’m still a month away from last frost, and my seedlings in the house have gone crazy. Some are 12″ tall and curling and laying over. How do I harden them off to move them outdoors?
Bradley Ward
When they are about 4-5 inches start setting then outside in the sun{as long as it’s above freezing} in increasing hourly increments and when they start to lay over support them with twine or chicken wire, or whatever works for you. After you cut the stalks for the last time in the fall you can add an inch or two of dirt or compost ( I’ve found that mushroom compost works wonderfully for mine) every year; this will give them a deeper root structure which will in turn make them less reliable on the support apparatus, but they will always need support after you stop harvesting them for the year.
Kimberly Doerr
I live in Northern New York, zone 3. My seeds are here. Is it ok to still start them.
Ashley Adamant
Yup. You can still start them and they’ll do fine. They won’t finish this year quite as big as ones started earlier, but they’ll still do great.
Bradley Ward
Yes, indoors, and then transplant after you’re sure there willn’t be another frost.
Lauralee Ledrew
My seedlings look alot like your seedlings in the individual cell tray. I was wondering I should repot them, maybe into 3in pots. I have 70 plants so they will take up much more space, which is very limited, but at the same time I dont want to risk killing them. I still have until mid june before I can plant outside.
Suggestion/Tips?
Laura
I started Asparagus in from seeds. This is my fourth year of growing. I’m now getting tons of little seedlings. What should I do?
Dig them up and give to friends
Dig up and throw away
Let live,
Tarry L Tett
First year growing asparagus. I understand the females rool but my asparagus is in raised bed. Do I cut ferns off
Or since they are new do I let them grow like ferns?
Ashley Adamant
They need to grow like ferns for 3-4 years before your first harvest.
Denise
What’s do asparagus plants look like when they first sprout? Do they automatically send up a “fern” or do they have 2 small rounded leaves first before a fern sprouts? I bought some send but they are tiny so I’m not sure they are actually asparagus? Is there anyway to send you a picture?
Ashley Adamant
They send up a very slender fern-like stalk.
Tricia
Mine is a slender stalk fern. Sorry new to gardening. Do we just let it grow for a year? Or cut it back at a certain length? We are in AZ not sure if it makes a difference.
Administrator
You want to let them grow like ferns for the first 3 to 4 years before harvesting.
Brenda Wolfe
I directly planted my seeds in the garden, they have come up gangbusters. Problem now is how and when to transplant, they are too close.
Ashley Adamant
I’d wait until the fall, after they’ve died back to the ground and started to go dormant (but before the soil freezes). At that point, you can carefully dig them with a potato fork type thing and gently separate the first year crowns and replant at propper spacing.
Bon
Can I keep the asparagus seeding in a pot for the first year instead of transplanting them on the ground? I presume the crown will have developed after a year when I could move them.
Also can you tell whether the plant is a male or female in the first year?
Ashley Adamant
Yes, you can just keep them in pots, but you’ll need big-ish pots for each crown (at least a gallon, preferably bigger, the crown roots get pretty big). The only way I know to tell the sex of asparagus plants is to let them cross-pollinate and see if any develop seed pods. Mine didn’t flower the first year, so I’d say you’re stuck waiting until they’re older to find the females (as far as I know).
Dale
What a great article and pictures to boot. We’re building a 4×12 raised bed for asparagus from seed as we prepare our home for retirement in 4 years… The asparagus should be just ready to start harvesting with our retirement. Thank you for the great informatin.
Ashley Adamant
Wonderful, glad I could help!
Gisela Lockie
I’ve grown 12 plants from seed this year (started in March) .They are now nice healthy little plants all in the same tray about 15cm tall.
I’m not quite sure I’ve got this right from posts above : I could pot each plant up individually and plant out into a bed once risk of frost over. If in pots or left in tray can they overwinter outside or must they be protected from frost in a greenhouse for example?
Your tips have been very helpful so far: many thanks!
Administrator
You could heel them in by planting them in pots in holes outside and covering with mulch.
Brent
Great article thanks so much. We’ve got 2x 30L pots of year ones grown from seed. There’s at least 8 plants in each pot, I know need to be thinned. Just wondering if they need to be brought in for the first winter? Thanks. Brent
Ashley Adamant
I’d suggest “heeling them in” which means basically planting the pots in holes outside, then covering with mulch. That keeps them at better temperature/moisture levels than you can maintain indoors. Good luck!
Brent
Mmmm, thanks can totally see that being worth it and if we could that’s what we would do. Unfortunately our place is a rental. Might have to insulate them above ground and cover. Hoping that so many baby asparagus can live together in such close proximityas well 🙄. Everything’s crossed 🤞🙄🤞
Ashley Adamant
You can do the same thing with straw bales, without digging at all.
Carlie
I planted seeds in August, now there are 4 little seedlings that sprout. I am here in nyc, zone 7b.
Do we bring them indoors now or heeling them in as you suggested?
Administrator
You could try heeling them in but I would be concerned that the seedlings might still be too delicate to survive the winter.
laura
Hello, this is the best article ive found on Asparagus, super helpful. I am growing it in a pot from seed, down here in central Mexico. So far they are thriving. They started as an experiment in a plastic soda bottle. It’s still warm here, but December and January can get cold at night. Im not sure if i should just leave them alone or go thorough the same process as the north?
Administrator
Depending on how cold it gets at night, the asparagus could be a bit more vulnerable to the cold when planted in a pot as opposed to being in the ground.
Barbara Jo Peto
Hello and thank you for your help.
Im in Illinois zone 5b, if I started my seedlings in January, would the seedlings be ready and strong enough to be placed in the garden in May or not ?
Ashley Adamant
Should be!
Melanie Fogle
I bought a place in north Florida it had asparagus growing all along the fence line. The neighbors found me gone and took most of them, but I was able to harvest some Male and a single female plant, but my pods are orange and not red as you have up north. And, quite a bit smaller than yours seem to be in the pictures. I brought 3 three 5 year asparagus plants with me, they rarely make it in the house. Between me and my dog we eat them right out of the garden, he also loves my tomatoes and will pick them himself. Great blog
Brandy Jaques
I planted 2 crowns last year and they did good, I left them as ferns all winter and cut them back in the end of winter. (Very small planting space). I was confused on when or how or if I should do that. One of them the base was covered in ice most of the winter, should I move them? It gets full Sun most of the summer it is beside a fence.. Also it’s 4 weeks till first frost date here in zone 5 b. Can I just plant seeds near the crowns and hope for the best? When would I do that? Thank you so much.
Administrator
Did you mulch them at all in the fall? It’s a good idea to add a layer of mulch to protect them against the winter weather. In the beginning you want to tops of the crowns to be about 2″ deep. You can cut them back anytime after they start to die off in the fall but it is recommended that you allow the dead foliage to stand through the winter and then remove it in the spring before the new shoots emerge. You can plant the seeds near the crowns if you wish. You may have to reposition them later if they all come up.
Sarah
I’ve been meaning to add asparagus to our garden for the last few years but the cost of the bare roots has stopped me. Knowing they are fairly easy to start from seeds means I will likely give them a try this year. Will be interesting to see how well they grow in my colder climate.
TOni
Finally, A gardening blog from someone in zone 4. So excited to find this. I Live in the high rockies zone 4a, 8k feet and mountain dessert terrain. According to the farmers Almanac I have no growing season or last frost date lol. I will be scouring your posts for information and planting my Asparagus indoors very soon.
Administrator
So glad you’re here. I hope you enjoy the posts.
Tina
These plants make a perfect side dish for any meal. I grow my own so I was looking for new ideas because I highly recommend trying to grow your own. It does taste better than the shop bought plants.
Jullie
Hello,
Very helpful article, wish I found this article last year!
I started my asparagus last spring/summer (2020). I live in 5b, so we will have our last frost next month.
Last fall I put hay after I cut the yellowish fern to put them to sleep. I just checked my asparagus bed this morning and there were one purplish spear about 2 inches tall and another one just about 1/4 inch. Those two were where the hay was a bit open (I can see the soil). I am wondering if I should move the hay covering them or just wait until the last frost?
And also, what should I do about the spears if there will be some/many as this will be their second summer? It’s tempting to try one LOL
Administrator
Removing winter mulch actually stimulates growth because the sun’s rays are able to reach the soil to warm it more quickly. You do want to wait until the danger of frost has passed though because heavy frosts can make the spears tough. As to whether or not you can harvest any of the spears this year, that all depends on whether you planted from seed or if you started with crowns. If you started last year with crowns then you should be able to harvest a small percentage for about 2 weeks. Then the following year you can harvest for the full 6 weeks.
Jullie
Hi!
Than you for the reply, that’s very helpful!
I planted them last year from seeds, so no harvesting spears at all this year?
Administrator
You’re very welcome.
Hugh Holland
Hi, can i start the seeds in darkness, or is light required for germination? Thanks
Administrator
Asparagus needs bright light for germination.
Faeterri Silver
After much searching this is the only article that mentioned spacing for a temporary bed. This is my first year growing asparagus from seed. I did start them early and have lots of seedlings. Lots of good information here. Thank you!!!!!!
Administrator
You’re very welcome. We’re so glad you enjoyed the article.
Christine
When potting on young ferns can they be buried a bit deeper for more stbility? or do they need to be planted at the same depth as they are whe they sorout?
Many thanks for your great article
Administrator
You’re welcome. We’re so glad you enjoyed the post. What kind of ferns are you potting up?
David Garber
typo: While at first, it may look like a huge harvest of asparagus seed, don’t count your eggs before their hatched.
they’re
Dave McCormick
how many years till the females make seed?….other than seeds, is there a way to tell female from male?
Administrator
They should go to seed the first fall after planting. The seeds are the only way that I am aware of to tell the difference.