How to Grow Asparagus

asparagus plant growing

by Jennifer Poindexter

Asparagus can be an intimidating vegetable and plant. When I was growing up, I remember my grandmother serving asparagus.

All I know is, as a kid, I wasn’t touching it. It smelled funny and looked odd, too.

As an adult, I’ve learned how to cook asparagus differently than my grandmother did, and it’s one of my favorite vegetables.

What’s even better is this crop is a perennial, is simple to grow, and can create many tasty meals. If you’d like to try your hand at growing asparagus in your yard or garden, here’s what you must know.

Growing Conditions for Asparagus

Asparagus is a perennial crop. You shouldn’t harvest the plant in the first two years, but once it’s established, your asparagus plants can produce a harvest for as much as two to three decades.

You’ll need approximately 20 plants per person in your home. Find a location that receives full to partial sunlight.

Ensure the soil is well-draining. Asparagus is actually a great candidate for raised beds if your soil isn’t what you feel it needs to be for successful gardening.

Once you locate the perfect spot, keep in mind that asparagus is a cool weather crop. Therefore, it’ll produce during the spring months while the temperatures are low.

If you live in an area where the weather is cool enough to accommodate asparagus at certain times of the year, have a location with some sunlight, and can provide well-draining soil, you may be able to grow this long-term crop with ease.

How to Plant Asparagus

You have the option of starting asparagus from seed or planting from crowns. Most gardeners purchase the crowns because it’s easier.

However, there are some benefits to growing asparagus from seed. It allows you to pick out the choice plants before adding them to your perennial bed, and it’s usually less expensive to start asparagus from seed.

If you choose the seed option, be sure to start them three months prior to the final frost date in spring.

Place the seeds in a tray with quality soil. Ensure they receive adequate warmth, some light, and are watered carefully but adequately.

When the plants have reached one foot in height, they’re ready for transplanting. Be sure to harden off your asparagus plants, for at least a week, before moving outdoors on a permanent basis.

Don’t transplant the seedlings into a perennial bed. Instead, place the plants in a large planter. Wait until the fall to know which asparagus plants should be moved to the perennial bed.

In the fall, you’ll be able to distinguish between the male and female varieties of the plant. The females will produce berries, and the males will not.

The males are usually better producers because all of their energy goes towards the harvest, not making future plants.

Therefore, you’ll want to transplant the males and discard the females, unless you desire the seeds for future plants.

You can transplant established asparagus plants in the fall before frost hits, or in the spring while the plants are still dormant.

Whether you’re transplanting asparagus plants you started from seed or asparagus crowns you purchased, the process will be virtually the same.

Begin by digging a trench in an area with all the grow space requirements mentioned above. All weeds must be removed from the planting area, and the trench should be one foot deep and wide.

Place one plant in the trench for every foot and a half. Add compost and fertilizer to the trench and create small mounds within the trench.

Put the crowns or transplants within the mound and ensure it’s sitting no more than a half foot beneath the surface in the trench. If the trench is too deep or the mound isn’t high enough to put the plant in a good position, it could cause issues for the asparagus.

Spread the roots out in the small dirt hills, cover them with soil, and water the plants. You can fill in the trench all at once, after planting, or you can fill the trench a little at a time as the plants grow.

The theory behind filling the trench in, a little at a time, is that it encourages stronger roots. I’ve always filled my trenches at once and haven’t had any issues, but this is a personal gardening choice.

Caring for Asparagus

Asparagus is very much an independent crop. It requires little care from its gardener to succeed. There are a few things you can do to help your harvest along, but outside of these items, asparagus can handle itself.

If you’d like to help your asparagus plants, make sure they receive adequate water for the first five years. This is a time where the plant is still becoming established.

Therefore, make sure you use the deep watering method to ensure the plants receive one inch of water per week.

If you’ve received adequate rainfall for the week, you may not need to water your crops. The best way to know is to use the knuckle test. Insert your finger into the soil next to your asparagus plants.

If the soil is dry to the first knuckle, it’s time to have a watering session. Make sure you water for longer periods, fewer days of the week to ensure the water reaches the roots. This type of watering will encourage stronger root systems.

The next thing you should do is mulch around your asparagus plants. This will help to retain moisture while also keeping weeds down. Weeds will choke your asparagus and steal necessary nutrients. Keeping them under control is vital.

Finally, at the end of the grow season, you’ll notice the fronds of your asparagus plants will turn yellow. When this happens, cut the plants back to an inch in height. This will help protect them over winter. 

Provide basic care to your asparagus plants, and they should grow well for you for years to come.

Garden Pests and Diseases for Asparagus

There are a few things you should look out for when growing asparagus. The first is cutworms. These worms will cut your asparagus off at the stem.

This will obviously damage your harvest. There are multiple methods for treating cutworms. You can apply an insecticide, or place diatomaceous earth or coffee grounds around the base of the plant. This will create a dangerous landscape for the worms to crawl over and ultimately result in their death.

Outside of this pest, you must be aware of two common diseases which are known to impact asparagus plants.

The first disease is fusarium crown rot. This disease lives where the soil doesn’t drain well. Unfortunately, once it’s there, it’s hard to get rid of.

Therefore, if your asparagus plants are showing signs of rot, it’s best to remove the plants all together. You can apply plastic sheeting over your soil to heat it.

This should kill the disease, but again, if the disease is in your soil it’s most likely because the area isn’t well-draining. Therefore, it might not be an ideal spot for asparagus anyway.

The last common disease you should be aware of is asparagus rust. This disease is a fungus which is spread in wet conditions usually by wind.

If this disease attacks your asparagus bed, the best thing to do is trim off any areas of rust. It usually appears at the top of your asparagus plants.

Clean up any weeds or garden debris around your asparagus. Make sure you burn any debris or pruning remains from this cleaning session because this fungus is highly contagious and will continue to impact your asparagus plants if not fully destroyed.

There aren’t many things which will attack your asparagus beds, but if you see any of the items mentioned here, be alert and move quickly to protect the health of your plants.

How to Harvest Asparagus

Harvesting asparagus, like everything else with asparagus, is quite simple. As mentioned earlier, you won’t harvest asparagus for the first couple of years to allow the plant time to become established.

When you begin harvesting in year three, only harvest for two weeks out of the grow season. In year four, harvest for three weeks. Add a week each year until you know the plants are well-established and can handle the harvest without damage.

You’ll know it’s time to harvest asparagus when the spear is a half foot in height. Asparagus is harvested in spring and early summer.

Cut the spear of asparagus at the soil level to harvest. It will regrow over the season, but it will return thinner and thinner with each harvest in the year.

Therefore, when the asparagus is only as wide as an ink pen, you’ll know you’ve harvested enough from the plant and to stop for the year.

After harvesting asparagus, rinse it with cold water, and store it in your refrigerator until you’re ready to use it.

Asparagus doesn’t have an abnormally long shelf-life, so be sure to use it within the first few days after harvest.

Growing asparagus isn’t overly complicated. The plant requires little care, but it can provide a harvest from one planting for as much as thirty years!

That’s amazing and something most gardeners should want in on. If you’d like a tasty, low-maintenance crop in your yard, consider growing asparagus.

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