Most gardeners love the idea of having an asparagus patch in their garden. But for some reason, many of us hesitate. Is it because the asparagus season is so short? Or maybe it’s because we just don’t know how to grow asparagus?
Either way, I hope this post will inspire you to actually plant a bed of asparagus this spring. Because I’m going to show you how to grow asparagus in a raised garden bed!
How to Grow Asparagus in Raised Beds
Asparagus is a perennial crop that you plant once and then benefit from for 15-20 years afterward. Because so many vegetables mature in mid-late June, it’s nice to have an early crop in the garden, a taste of what is to come!
When it comes to starting an asparagus bed, the first thing you need to decide is whether you’re going to grow asparagus from seed or crowns.
Option 1: Start Asparagus from Seed
The benefits of starting asparagus from seed are as follows.
- Seed starting asparagus is much cheaper than purchasing 2-3 year old crowns.
- Asparagus started from seed will produce both male and female plants, making pollination and seed saving possible (only females produce seed).
- You have more asparagus varieties and options available to you.
And here is the down side of starting asparagus from seed!
- Seed starting is more labor intensive.
- You have to wait 4-5 years before you can freely harvest from your asparagus bed.
- You’ll lose about 1/3-1/2 of your seed starts to female plants. Only male asparagus are thick and chunky, worth growing for the table.
Starting asparagus from seed is the frugal option, but it takes quite a bit of time and effort on your part! Or so I’m told. I’ve never tried, but my online acquaintance over at Practical Self Reliance, has. You can click this link here to read Ashley’s article on how to grow asparagus from seed.
Option 2: Start Asparagus from Crowns
The other (and perhaps the most common) way to grow asparagus is from crowns (aka roots). Many seed companies sell 2 year old asparagus crowns.
Benefits of purchasing crowns are listed below.
- You won’t have the extra hassle of seed starting and transplanting.
- Crowns are supposed to yield their first harvest the spring after you plant them.
- Most seed companies sell only male crowns which means (unlike seed starting) every root should produce thick, chunky spears.
The negatives that come with purchasing asparagus crowns?
- The cost is higher than purchasing seed.
- You’ll have less selection available to you.
- Unless you happen to get a female plant or two, seed saving isn’t an option.
Because I only have experience with asparagus crowns, that’s what the remainder of this post is going to be about! Let’s dive into the particulars of how to grow asparagus!
Step 1: Tips for Ordering Asparagus Crowns
When it comes to purchasing asparagus crowns, there are a few things you to think on and know about!
- Make sure asparagus varieties you chose will grow well in your gardening zone.
- Place your order 4-6 months ahead of time to ensure the company has stock.
- Don’t expect to see your asparagus until spring; companies won’t ship it until then.
- Make sure you don’t order too much!
Asparagus has wide-spreading roots and it doesn’t take very many crowns to fill a garden bed!
On average, each crown should be given an 18 inch in diameter circle for growing, expanding and creating more asparagus. In a 3×8 ft raised garden bed, this means you only have the width for 2 rows. With 18 inches between the center of each root crown, an 8ft row can only hold 5 asparagus.
That means to fill a 3×8 ft raised garden bed, you only need to order 10 crowns! I know it doesn’t sound like much. But remember that the roots will create many more asparagus shoots in the garden bed!
Step 2: How to Keep Your Asparagus Crowns Alive Until Planting Time
If ordered online or via a seed catalog, your asparagus crowns will arrive by mail. When you order, you’ll have to enter information about your growing zone. The company will then do their best to ship your roots to you around planting time.
Sometimes, crowns arrive a little before the planting date in your area. And you have to go through the extra work of keeping them alive.
But don’t worry. It’s not hard! Leave them in their box and keep the long white roots just moist by lightly spritzing them with a spray bottle every couple of days.
Until you plant, asparagus crowns should be stored in a cool place. I kept mine in the cold room, but I have acquaintances who actually refrigerate the box, keeping things moist and cool in that fashion.
If your roots start shriveling up, it’s a sign they’re drying and out (and dying). So keep them lightly moist and they should remain plump and full.
And if they start showing signs of mold? Snip off the moldy bits and let them breathe a bit more!
Step 3: Prepare Your Garden Beds for Asparagus
When it comes to the asparagus raised garden bed, you need to ensure three things before planting!
Asparagus likes soil that is basic in it’s composition (6.5-7.5 pH). So if you have acidic soil, you should amend it before planting asparagus (many people use lime), or your crop may not do well.
Asparagus roots must be planted deep in the garden bed. For this reason, you want about 16 inches of rich, loamy soil for planting.
Last but not least, asparagus is a heavy feeder and needs lots of rich, nutritious soil to produce the thick, heavy asparagus spears we all want! Make sure your raised garden bed contains lots of composted matter.
Step 4: When to Plant Asparagus Crowns
Asparagus crowns are typically planted in the spring, as soon as the soil can be worked and 3-4 weeks before your last average frost date.
If your crowns are looking dry, it might be a good idea to soak them in water before planting, just to make sure they’re fully hydrated before going into the earth.
Fill a bucket with water and submerge your bundle of crowns for about an hour. And then? It’s time to plant!
Step 5: How to Plant Asparagus Crowns
Asparagus crowns need to be planted deep and spaced far apart. You can dig individual holes or plant the roots in trenches.
Either way, asparagus rows should be 18 inches apart and each crown should be planted 10-12 inches deep. Here’s how to plant asparagus crowns in a raised garden bed!
- Measure off the spacing between your asparagus rows (they should be 18 inches apart).
- Also measure the spacing within each asparagus row (crowns should be spaced 18 inches apart).
- You can then dig a trench or holes for planting your asparagus crowns.
- Each hole (or trench) should be 12 inches wide by 10-12 inches deep.
- Once dug, create a 3-4 inch tall mound every 18 inches for your asparagus to rest on top of.
- Drape a single crown over a mound with the knobby side up.
- Fan the roots out in full circumference around the knobby center.
- Set up all your crowns and then cover them with rich, fertile soil.
- Make sure the base of the crown is covered by 2-3 inches of soil.
- Mulch the garden bed with 2-3 inches of old, rotting straw to keep weeds down.
- Watch, wait and refrain from harvesting spears that appear!
Step 6: Caring for Asparagus Plants
Your asparagus plants need lots of nutrients, so you’ll want to add composted matter to the soil at least 1x a year, preferably in the spring.
It’s also a good idea to keep the beds mulched with rotting straw, hay or lawn clippings. Not only does this suppress the weeds, but it helps hold moisture in and eventually, these things will break down and add nutrients to the soil itself.
And whatever you do, don’t harvest spears the same spring you plant! Asparagus roots need to establish themselves and harvesting in the same year often delays growth.
The spring after you plant, you should be able to harvest from your garden bed. Most recommend that you only harvest for 2-3 weeks.
But by the 3rd spring, you should be able to harvest for 6 weeks without a worry!
Over the years, your crowns will put out more and more shoots. Eventually, you may want to dig up and transplant some of them to another bed.
Step 7: Transplanting Asparagus to a New Raised Garden Bed
Once established, asparagus beds will produce for an average of 20 years. If the bed becomes too crowded during this time or you have the desire to start a new patch, go ahead and dig starts for a new raised garden bed.
Starts should be dug up in early spring, before any signs of life are present. Once the large and wide-spreading roots have been removed the dirt still intact, you can transplant them to a new raised garden bed, using all the techniques you implemented the first time!
Be sure to fill the holes in your old bed with rich soil and tender young asparagus spears will likely appear in these places within the next several years!
Want to get my favorite home canning recipe for asparagus? Click this link here to see it!
Growing your own asparagus isn’t as difficult as is appears to be. The hardest part is waiting. But if you can hold out for just a few years, you’ll have an asparagus patch the produces for years to come!
And that is a beautiful thing!