Everything You Want to Know About Growing Asparagus
Asparagus is the most worry-free perennial vegetable plant there is for the home gardener. If you love asparagus as much as I do, you know how expensive it is to buy. I will share with you everything you want to know about growing asparagus so you can enjoy your own asparagus crop for years and years.
Don’t Put Off Tomorrow What You Can Grow Today
I grew up with wild asparagus beds right outside our front door, I was quite spoiled. When I moved into my own home I knew I wanted to add some asparagus beds so I bought asparagus seeds. Unfortunately, I read the back of the package, after I made the purchase, and saw they take three years to harvest?? I had no idea that growing asparagus took so long. I am a very impatient gardener and had no intention of waiting three years to harvest my asparagus crop so I placed the seeds in the freezer. Guess what? Ten years later those seeds were still in my freezer! I could have planted those seeds when I bought them and enjoyed the harvest for the previous seven years. Instead, my impatient behind had frozen asparagus seeds.
All About Asparagus
Asparagus is a perennial vegetable, meaning you plant it once and enjoy it for years and years. I recently learned of an asparagus bed that was 100 years old and still producing! Talk about wise investment. Asparagus is generally ready for harvest in early spring and in the right conditions, you may even have a bumper crop (see growing asparagus below).
This beautiful green vegetable is rich in vitamin K, vitamin C, iron, vitamin A, calcium, and much more. Some may even refer to asparagus as a superfood. Asparagus can be eaten raw or cooked, however, studies show that cooking asparagus helps your body absorb its nutrients.
Male or Female
Asparagus plants are monoecious (I had to look it up), meaning each individual plant is either male or female. Some varieties of asparagus, such as ‘Jersey Knight” and Jersey Giant’ produce all male or primarily male plants. All male, or predominately male, plants are more productive because they don’t invest their energy into producing seeds. Therefore, male plants send all their time sending up harvestable shoots for you to enjoy.
In the fall, the asparagus stalks will produce a fern from their top. If your asparagus is a female, they will grow red berries that you can save and plant in the future. After the fall, your asparagus plants will turn brown and die-off for the winter. Later to emerge again in this spring!
If a higher yield is your goal in growing asparagus, then you should choose an all-male variety. However, a good male/female variety is Mary Washington. Mary Washington asparagus is one of the most common asparagus varieties.
As I mentioned above, asparagus is a perennial, which means it comes back year after year. It’s important to pick a good location for your asparagus because this is where it will live for years to come. Asparagus is a hardy perennial that can grow in Zones 3 to 8, asparagus grows best in well-drained soil with a near-neutral soil pH between 6.5 and 7.5. You can grow asparagus from seeds or crowns. Asparagus Crowns are year old (or older) rhizomes.
Location, Location, Location
Asparagus needs loose, compost-rich soil. It does best in lighter soils that warm up quickly in spring and drain well; standing water will quickly rot the roots. It can withstand some shade, but it really prefers full sun. You want to be sure your site is in an area where it will not be endangered when you cultivate your garden. We planted ours directly in our garden at the far end, so as not to interfere with other gardening tasks. It is always in the direct sun and our growing season runs from March til around the end of September. It slows down around that time and I usually let it rest a while without harvesting it; then I cut it off at the ground in late October, early November depending on temperature and its health.
Raised Beds or In The Ground?
In hindsight, I wish I had put them in a raised bed. When I next increase our plantings (by propagating my own seeds), I will put the new ones in a raised bed next to the garden. Some people do soil tests and amendments based on the recommendations of university and government studies. I do not do that and in all my years of gardening, I have never had an issue. We mulch and add compost and organic fertilizer from our farm.
How do you grow asparagus in a raised bed?
You want your planting bed about 4 feet wide and to remove all weeds and roots. You will plant your crowns in the middle of your bed. You want to add plenty of aged manure or compost as well. Pretty much like you would any bed preparation. Asparagus has a strong root system that spreads as much as 6 feet horizontally and can go 6 to 8 feet down.
How long does it take to grow and harvest asparagus?
When you plant asparagus from seed, it can take up to three years before you can harvest the plant. The edible part of the asparagus plant is the young stem shoot, asparagus spears, which emerges as the soil temperatures rise above 50 degrees Fahrenheit in spring. If you plant crowns, usually they are already one year old so you can expect to harvest them in as little as two years.
I am sure you have noticed I don’t say “planting” asparagus, I say “transplanting.” Asparagus seeds have to be planted so deep below the soil line that it impedes their development. Seeds are started (just like any other seed) in cups and then transplanted to the garden. Remember, while you can order seeds or crowns, the bed preparation is the same.
For crowns, dig a trench 12″ deep down the middle of your 4-foot row. Plant crowns 1’ – 2′ apart in it. Cover the crown with about two inches deep in the soil. As shoots emerge, cover them with another two inches of soil, continuing this pattern as the plants grow, until the soil level reaches the top of the trench. In very sandy soils, you will probably be okay filling in the trench when you plant the crowns, but you must be sure your soil is “very sandy.” Trenches should be 4’ apart. Plant in spring or, in milder climates, late fall/early winter.
Starting asparagus from 1-year-old crowns gives you a year’s head start over seed-grown plants. Two-year-old crowns may seem enticing, but they tend to suffer more from transplant shock and by the time they recover, they won’t have produced any faster than 1-year-old crowns.
Moving Asparagus After It’s Planted
I have been asked about transplanting or moving mature crowns to a different location. While technically this is possible, my advice is to forget it! Crowns more than two years old are generally huge and it is very difficult to get them out of the ground in one piece. The transplant shock is very great for these more mature crowns and the end result is that the moved crowns usually die. Even if they don’t die immediately, you are probably moving, along with the crown, the root rot organisms that almost always infect them. In their weakened condition, the crowns will fall victim to the disease more quickly.
Do asparagus plants spread?
Asparagus plants do spread. The crowns grow and send out new shoots that will produce more asparagus. However, after a period of time, you may notice the size of your spears diminishes. Once this happens, you will need to dig up your crowns and divide them. Dividing your crowns will increase your yield and grow your asparagus bed. To learn how to divide asparagus crowns, click here.
As I mentioned earlier, asparagus are very hardy plants. I won’t go as far as to say they you will never have a problem. The two main issues gardeners may have to deal with when growing asparagus are beetles and rust. In addition to the beetle and rust, sometimes critters enjoy the fruits of our labor. To keep deer and other pets out of your garden, click here for our tricks of the trade.
- Asparagus Beetle. Asparagus Beetles are the main pests that plague asparagus. They can be hand-picked early in the morning and rarely require chemical treatments. They make a perfect snack for chickens.
- Asparagus Rust. Asparagus rest is not a pest but a disease. Fortunately, it’s not very common but left untreated, it will kill your asparagus plants.
Preserving The Harvest
After you grow and eat your asparagus, you will want to preserve your harvest so you can enjoy it all year long. Here are a couple of great articles on how to preserve asparagus.