Once established, asparagus will return year after year.
If you’ve ever wanted a crop that takes little effort but provides you with years of value, it’s time to think about asparagus.
Asparagus is a perennial vegetable–meaning it comes back every year. Once you’ve established your patch, you’re likely to get up to two decades of harvesting. It’s that prolific!
The key to a long lasting crop is to give your plants everything they need from the beginning. Read on to find out how to plant your asparagus patch right–the first time.
Where does asparagus grow best?
Asparagus is a cool season crop, meaning it thrives in early spring, when the weather is chilly and moist. It needs a fairly cold winter to accommodate its dormant season, and tends to do best between growing zones 3 and 8.
The main necessity for homegrown asparagus is good drainage. Locate your bed in an area with loose, well-drained soil augmented with sand or horticultural grit where necessary. (More on soil preparation below.) Also ensure that your bed receives at least eight hours of full sunlight per day in summer. If you’re not sure, use a sunlight calculator.
Choosing your plants: seeds or crowns?
Growing asparagus from seed is one way to get started, but this method will add several years to your overall timeline. Typically gardeners buy asparagus crowns. These are the roots of 1 to 2 year old plants attached to a small base where the sprouts will emerge.
Crowns can be shipped through the mail, but will usually arrive slightly dry and may be brittle. When you’re ready to plant, soak your crowns in a bucket of water. Soaking for an hour is all it takes to get them ready for planting.
Asparagus crowns, by Krish Dulal, CC BY-SA 3.0
When to plant asparagus
The best time to plant asparagus crowns is in March or April. Plan for a time when you can easily work the soil. The water table should be well below your asparagus bed all year round. If growing your asparagus from seed, start in seed trays in February. Bright lights suspended overhead will help improve outcomes for your plants.
Preparing the soil for your asparagus bed
The most common way to plant asparagus is using a trench. Begin by digging a hole 16 to 18 inches deep and 12 inches wide. Determine the length of the trench by the number of plants per row. Each plant will need 12 inches of space on either side. If you’re planting more than one row, ensure spacing of 12 inches between rows as well.
Once you have your trench, loosen the bottom by inserting a digging fork into the soil and rocking back and forth. If your drainage isn’t ideal, now is the time to add sand or horticultural grit to the trench bottom. Top this off with finished compost or well-rotted manure and mix well.
Related: How to Use Finished Compost
Using the compost and drainage mixture, hill up your soil at the bottom of the trench into raised rows. These will support your plants and help the roots lay at the best angle. Place soaked plants crown side up, with roots evenly distributed along both sides of the ridge.
Cover with about 4 to 6 inches of soil and water well.
Caring for your plants: how and when to harvest asparagus
Over the next few years, plants will form deep roots that will make digging without damage difficult. And here’s the hardest part about planting asparagus: the first year after you plant, don’t harvest anything from your patch. Your plants will be building strong roots to carry those perennial plants forward into the future. Harvesting too early risks long term-damage to the roots and crowns. Instead, add some organic fertilizer in early March, before shoots emerge. Water the plants during any dry periods and keep them as healthy as possible.
Avoid harvesting asparagus spears until 2 to 3 years after you first plant your crowns. This will help plants establish strong roots and ensure a long-term crop.
The second year after planting, asparagus can tolerate the harvest of a few spears (less than half of the plants that emerge). Just be sure they’re at least six inches tall. Let the rest grow into ferns, knowing your plants are still building their roots.
Related: How to Prepare Your Asparagus Bed for Spring
The third year after planting, you can harvest your patch liberally. It’s still a good idea to fertilize before shoots emerge, but you can now check daily and harvest as needed. Depending on where you live, you may have up to 10 weeks of fresh eating. Stop picking by the beginning of June and resist the urge to cut down foliage as the remaining plants grow large and feathery. This is their way of saving up energy for next spring.
When the harvest is over, leave your asparagus plants to fully develop before cutting back in fall. This will help them store up energy for next year.
Weed gently by hand and water as needed during dry summer spells. Installing a drip irrigation line on your beds is one way to water without fuss. In fall, when the plants start to turn yellow and die back, it’s time to cut them down to ground level. Apply a layer of mulch to protect your plants during the winter season.
Frequently asked questions
How much asparagus should I plant?
If you’re growing for a family who likes to eat asparagus regularly while in season, 40 to 50 plants will provide lots of good eating. Ten plants are usually adequate for a single gardener.
Do asparagus plants come in male and female varieties?
Yes, they do. Most asparagus plants sold by nurseries will be male plants, as these tend to produce larger and more prolific spears than female plants. The popular Jersey Knight asparagus is a predominantly male variant.
What if I need to move my asparagus patch?
Avoid moving asparagus plants wherever possible, since moving them severs roots and sets growing back several years.
Can you grow asparagus from cuttings?
Asparagus patches that have started to slow their growth are usually ready for division. After trimming back plants in the fall, dig up crowns and cut them into pieces, making sure each one has plenty of good roots attached. Replant each piece for a new, stronger plant. Repeat the process described above for waiting to harvest.
Can you grow asparagus in a container?
Asparagus plants aren’t ideal for container growing, because constrained spaces reduce their lifespan. Given that they take several years to get established, a three to four year harvest may not seem worth the effort. Having said that, it can be done.
What are the different stages of asparagus growing?
Asparagus plants start off as seeds or crowns before emerging from the ground as spears. When left to grow further, they become tall, fern-like plants reaching almost 7 feet. Late in the season, they will usually flower and produce small, poisonous berries. Asparagus plants experience one growth period and one dormancy period each year.
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