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How to Harvest and Grow Asparagus [Complete Growing Guide]

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Truth is, every gardener (and even people who don’t enjoy gardening) should grow asparagus. It is one of the easiest vegetables to grow, most people like to eat it, and it regrows all by itself, year after year. It can be a little finnicky to establish, so I’ll give you some tips on how to grow asparagus. 

Farmer showing off their considerable asparagus harvest.

Asparagus is a perennial vegetable (see the best perennial vegetables for your survival garden here!), my favorite. No replanting every year, this veggie will happily grow for many years. Asparagus looks quite stunning in a garden too, it should be part of the top 10 most beautiful vegetables

It takes at least three years for Asparagus to establish properly. You might get a small harvest in the second year, but a full harvest won’t be until the third.

How to Grow Asparagus

asparagus spears growing in the garden
Asparagus growing in the garden

Asparagus Growing Stages

There is no doubt about it, asparagus is a very unusual vegetable! Asparagus is actually the young growing step of a complex underground root system called a crown. Left unharvested, each spear would grow into a 6-foot-plus fern-like plant.

During the harvest season, an established asparagus crown will send up many shoots, which are harvested when they are around 6 inches tall.

This may sound simple, but growing asparagus is a long-term project! Asparagus growers advise that it takes up to four years from sowing seed to your first proper harvest. Definitely not a crop for a gardener in a hurry!

How Long Does Asparagus Take to Grow

Growing asparagus from seed or young crowns is a lengthy process. It is advised that crowns are not harvested for the first two years to allow them to become fully established.

But when the first proper harvest finally arrives, you’ll be mindblown by the speed at which asparagus spears grow! A healthy crown can throw up spears that grow by as much as 2 inches per day.

So, if your asparagus bed has started to show signs of the first shoots, it is worth checking and harvesting every day or two. If left to grow too large, asparagus spears can become tough and woody.

Asparagus Growing Tips

I like to start my Asparagus from seed, but I’ve started them from crowns as well.

Mary Washington has been the best performer for me, and that’s what I’ll stay with from now on, but the purple varieties came out quite well also. Plus, they taste great!

The main differences between Asparagus grown from seed and those grown from crowns are the time it takes to harvest, and the adaptability of the plant itself.

From seed, it takes 3-4 years before you’ll have a good harvest. From crowns, it takes as short as 1 year.

My main reason for growing them from seed is that I have found seed-grown plants to be stronger and they adapt better to their surroundings.

This doesn’t just apply to Asparagus actually, I find it to be so with most other fruit or vegetable plants as well. I’ve chosen to grow some grafted varieties of fruit trees, mainly for the quality of the fruit, but the seed-grown varieties are hardier, need less water, are less susceptible to heat or cold stress, and so on.

How to Grow Asparagus From Seeds

Asparagus is easy to grow from seed. I like to soak them in a little bit of warm water overnight, then plant them out in a well-draining seed-raising mix (this is a good one). Plant them as deep as the thickest part of the seed.

Within days (2 weeks max) you’ll see a little shoot. This shoot won’t stay little for long, they’re exceptionally fast-growing!

Asparagus plants will be productive for 15-20 years, so make sure you plant them in the right spot where they can stay. They do NOT appreciate being moved!

I like to start my seed in small pots (like these ones), then plant them out in the garden.

If you’re sowing them straight into the ground, plant them in trenches or deep furrows. The crowns need to be below the surface of the soil once they’re fully grown, which is hard to achieve if you sow them at soil-level. As the plant progresses, fill up the trench.

The following diagram by Cornell University illustrates the idea:

Asparagus sends roots out from the crown, which looks like a great big brown spider with many, many legs. These roots and the crown need to be under the soil, where it’s moist and dark.

How to Grow Asparagus Crowns

The same applies when you buy crowns instead of seeds.

Plant the crown on a furrow and make sure the crown is fully covered with soil. The furrow is like a raised little bed for the center of the crown, so the roots can snake down from it. Kind of like a seat for its bottom, with its legs hanging down.

If you do buy them as crowns, give them a good soak before you plant them. You can add a little seaweed solution (like this one) to strengthen them. Plant them 2-3 feet apart.

Make sure you plant them the right way up!

Sounds really silly, but it can actually be a bit tricky to tell because they have dry stalks from last season, and they can look like roots. The easiest way is to hold the crown in your hand and see which way the long roots fall most naturally.

How to Grow Asparagus From Cuttings

It is not possible to grow asparagus from cuttings taken from the plant, but you may have some success in dividing asparagus crowns to create more plants.

However, asparagus crowns do not like being disturbed, and it may take them two years or more to become re-established and robust enough to produce a viable crop.

Bearing this in mind, it makes more sense to plant new asparagus crowns alongside your existing plants, rather than attempting to divide the crowns you already have.

Where to Grow Asparagus

asparagus-plants-roots

Again, remember Asparagus is a perennial, permanent vegetable. It can’t be transplanted once it has established itself, so make sure you choose the right spot for it.

It will grow in most ordinary gardens, as long as your soil is well-draining. If your soil is high in clay or doesn’t drain well, enrich it first with gypsum or lime, compost, sand, and mulch. Read more about how to improve your soil naturally.

Asparagus prefers shelter from strong winds. It copes well with the hot sun, but make sure it’s well-mulched to keep the moisture at soil level. This is a great mulch. They appreciate regular watering.

Asparagus needs your soil to be fairly loose. If you’re a no-tiller, prepare your bed beforehand with piles of manure and mulch, to decompose and provide great soil for the Asparagus. Read more about how to prepare a garden without a tiller.

If you’re not against digging – dig! Dig the soil, dig manure and organic matter through, and make it nice and loose for Asparagus’ roots to go forth and conquer. You’ll want loose soil at least 16 inches deep.

Can You Grow Asparagus In a Pot or Container?

If you are gardening in a small space such as a balcony, it is possible to grow asparagus in a container.

Asparagus plants are hungry feeders, so you will need to regularly feed the plants and provide additional compost. Yields will be lower than plants grown directly in the ground, but you should still get a reasonable crop after a few years.

How to Fertilize Asparagus

Asparagus loves food!

Fertilize regularly, or grow in companionship with Comfrey plants (check out this amazing healing comfrey balm you can make yourself!), which provide you with free green mulch (high in nitrogen!) to cut and mulch around the Asparagus plants.

These two grow well together. Comfrey’s roots unlock nitrogen, which is then available for the Asparagus to use. It also doesn’t grow too tall, so won’t compete for the sun with Asparagus. (Where to buy Comfrey plants)

You’ll need to fertilize at least twice a year, depending on the type of fertilizer you’re using. Give them a good dose of vegetable fertilizer. I love Dr. Earth‘s range of fertilizers.

The best time to fertilize asparagus for the first three years is in the early spring before the first spears appear. For the fourth year onwards, apply fertilizer after the final harvest.

The best fertilizer for asparagus is a balanced formula with equal amounts of nitrogen, phosphorous, and potassium, such as a 10-10-10 blend.

Once you’ve harvested your crop, give them a heap of composted manure, and make sure the mulch cover is still going strong. If it isn’t, reapply!

asparagus field.
See, furrows!

How to Harvest Asparagus

You can harvest your first small crop in the second year (if grown from crowns). Cut two or three stalks from each plant, but don’t cut too many. Leave the rest of the plant to grow up so they turn into nice big fern-like plants.

I lost a whole crop a few years back, so I’ve since adopted a different method of harvest. I used to have no particular method at all, just snap it and often eat it right there and then.

Once I researched why I lost them (which appears to be a combination of rust and my gung-ho method of chopping), I found out that you need to be a little delicate when you cut them. There is an embryo shoot inside, and it is easily destroyed which leads to the crown dying.

Follow the stalk all the way down, with two fingers, right down into the soil, and gently pull outwards, away from the crown. It will snap all by itself, at the perfect place!

If you need to cut lots of plants this is not an effective method. My kids love to help me with harvesting, so I’ve since bought a special Asparagus knife to use. It’s the same kind of tool you’d use for dandelion roots. (By the way, do you know the difference between dandelions and wild lettuce?)

The tops of the Asparagus plants will start to die off in the fall. Cut them off, and mulch the plants well, once again.

You might want to consider burning the dead stalks or putting them in a plastic bag and tossing them in the trash immediately, rather than composting them. Asparagus is susceptible to rust and doing this can help prevent spread.

When to Harvest Asparagus

It is important to time your asparagus harvest perfectly to get the best possible yield. In the third year after planting crowns, you can harvest the young spears for three to four weeks, then leave the remainder to grow into ferns. For every year after this, this can be extended to up to eight weeks.

Traditionally, the last asparagus harvest should be no later than midsummer’s day. This allows the crown to grow sufficient ferns to provide enough energy for the following year’s harvest.

How to Grow White Asparagus

Freshly picked natural organic bunch of white asparagus vegetables on a wooden background
Freshly picked natural organic bunch of white asparagus vegetables on a wooden background

I’m not a huge fan of this. Too much work for not much outcome, I say, but some people (my mom and dad for example) love them. I guess they’re a bit of a delicacy.

If you want white asparagus, you’ll need to keep the soil around the sprouts piled up. Create hills around the stalks to prevent the light from reaching them, which results in white asparagus stalks.

You’ll need to hill up at least once a week, right throughout the harvest season. This can take 6-8 weeks. Don’t forget to take the hills down once your harvest is finished.

Green vs White Asparagus

White asparagus and green asparagus spears are grown from the same plant species but using different growing conditions. Green asparagus is undoubtedly easier to grow, but white asparagus is considered a delicacy and is the type of asparagus normally used for canning.

The secret to growing white asparagus is to ensure the developing spears are not exposed to light. This stops the development of chlorophyll, which gives plants their green color.

To grow white asparagus, you need healthy crowns that have been in the ground for at least three years. When you see the first shoots of asparagus in late spring, it is time to cover the plants to exclude light.

There are several methods you can use to do this:

  • Mound at least six inches of soil over the asparagus crowns
  • Use black plastic over row covers or plastic hoops
  • Place plastic tubs upside down over each asparagus crown
  • Build a wooden box over the asparagus bed during the cropping season

And while we’re on the topic of different colors of asparagus, did you know you can also get purple asparagus? This is a selectively grown variety that has a beautiful purple color. Sadly the spears turn green when cooked, but they can be eaten raw as a vivid addition to a salad.

Transplanting Asparagus

The root system of an asparagus crown is incredibly complex and takes several years to become fully established. It is possible to transplant asparagus, but it can result in lower yields or even the death of the plant.

After transplanting asparagus, it would be better to avoid harvesting any spears the following year, to allow the plant to re-establish a strong and healthy root system.

When transplanting asparagus crowns, do so when the plants are dormant in late fall or early spring.

Using a garden fork, carefully loosen the soil around the crown and then lift the entire crown out of the ground. The more care and attention you pay to preserving the delicate root system, the better chance of your asparagus crowns surviving the move.

Plant the crowns as you would a new crown, in a furrow with plenty of compost. Keep them well-watered in dry weather until they become established.

Asparagus Diseases and Pests

Asparagus is actually pretty good, disease-wise. It’s not a fragile little flower and won’t cave in at the drop of a hat.

But, as I mentioned above, rust sucks. It really does.

Rust is easily identified, it looks like it sounds; rusty.

It attacks all plants, young and old, and it doesn’t look good at all. It’s a fungal disease, and burning the old stems is a great way of preventing the spread of fungi. Once you have rust in your plants, you can try anti-fungal spray (this is an affordable, popular one), but I have not had a lot of luck with it and I hate spraying the garden with anything.

After my failed harvest, an old farming neighbor told me his mother used to add ashes to the soil once a year for prevention.

Asparagus-Beetle

I’ve since applied ashes every year and rust has not happened again. Whether this is science or luck, not sure, but I’ll use ashes every year, just to be sure.

Another attack may come in the way of the asparagus beetle.

It’s pretty cool looking, not cool to have. It lays eggs on your new juicy shoots in small holes. They can affect the crown itself too.

Once you see one, you’ll see 1000! They seem to come out of nowhere. Chickens are the best pest control for these guys, your girls have a great time scurrying around and pecking their little hearts out. Read more about keeping chickens out of your yard, if needed.

If you don’t have chickens, you’ll need to resort to another form of pest control, possibly in the way of neem sprays, like this one.

How to Eat Asparagus

Asparagus is a versatile vegetable that can stand up to a range of different cooking methods. Steamed tender asparagus is one of the best ways to preserve the taste, texture, and nutritional value of this vegetable, and they require just three minutes in a steamer basket to cook perfectly. Alternatively, they can be boiled or sauteed for around two minutes.

For something different, asparagus spears that have been roasted or griddled develop a delicious caramelized outer surface. This is a great way to bring out the sweetness of asparagus spears, as well as add a slightly crunchy texture. Griddling also creates dark lines along the green spears, which look great on top of a salad or quiche.

What Part of Asparagus Do You Eat?

Theoretically, all parts of an asparagus spear are edible, but some parts are more tender and flavorsome than others.

At the tip of each asparagus spear, you will notice a bunch of delicate buds – this is the best part of the asparagus! If you wish you can serve just these parts as a delicacy, keeping the rest of the stem aside for making soup.

Working down the stem, you will see that it gradually gets wider. The upper thinner section is new, tender growth, while the lower thick section is older and tougher.

Whilst all parts are edible, the thicker section takes far longer to cook than the tender upper part. Most chefs remove the woody lower stem and discard it.

To prepare an asparagus spear for cooking, grasp the bottom of the stem in one hand and the upper part in the other. Bend the stem firmly until it snaps into two pieces – the point where it snaps is where the tougher part of the stem finishes.

Can You Eat Asparagus Raw?

Asparagus can be eaten raw, and this is one of my favorite ways to enjoy the first asparagus harvest of early summer! Raw asparagus tastes great in a dressed salad or as a crudité, dipped into homemade houmous.

All varieties of asparagus can be eaten raw, but the skin of white asparagus should be peeled first. The bud and upper third of the asparagus spear are the most tender sections and can be eaten just as they are.

Alternatively, the spears can be thinly sliced on a long, diagonal line to create delicate slices of raw asparagus to add to a salad.

How to Store and Freeze Asparagus

Asparagus is one of those crops where you suddenly have an abundant harvest on your hands! While asparagus is at its most nutritious when eaten as fresh as possible, it can be stored for some time in the refrigerator or freezer.

Can You Freeze Asparagus and How?

As the growing season of asparagus is quite short, it makes sense that we might want to freeze any excess to ensure a year-round supply.

Asparagus can be frozen, but the high water content means that the texture of the asparagus can become soft and mushy when it thaws. 

Blanching asparagus spears can help to preserve their texture and keep them in the best possible condition in the freezer.

Alternatively, you can lightly roast or griddle asparagus before freezing. When prepared in this way, the spears are perfect for adding to dishes such as quiches and omelets.

How to Store Asparagus

The best way to store freshly harvested asparagus spears is in the refrigerator. To keep them crisp and preserve the nutritional benefits, stand the base of the spears in a jar with around an inch of water in the bottom.

Cover the tips of the spears loosely with a plastic bag, and store the jar upright in the fridge. Change the water if it becomes cloudy, and remove any spears that start to look past their best.

How Long Does Asparagus Last

If you follow the ‘water in a jar’ storage method, asparagus spears can be kept in pristine condition for up to two weeks in the refrigerator. This is very helpful if your plants are in the early stages of cropping and do not produce enough for a whole meal in one harvest.

Do you grow asparagus? Keen to get started? Any great tips your grandparents told you about growing asparagus? Let us know in the comments below!

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3 Comments

  1. Thank you for your advice. I live in central Florida (zone 9b). My asparagus (crowns, Mary Washington) bed is now in it’s second year. I have not harvested; spears are pencil thick, and I want them to wait until next year. Can I harvest next year, or wait another season?

    1. Hi there James!
      You’re in a similar climate to me – yay to warmth!
      Nice work on the asparagus – they’re such a productive plant.
      You can harvest them lightly in the first year so they build up strength in the crowns first. A light harvest can encourage it to growth.
      The rule we follow is the ‘pencil’ rule. If they’re thicker than a pencil, we cut them before they branch. If they’re smaller, we leave them to feed the crown instead. Having spears at pencil thickness is a great sign for a good harvest next year!
      I usually cut them at around 8″ tall but I’ve been known to cut shorter spears (as long as they’re a ‘pencil’ or thicker) when I’m out in the garden and fancy a snack.
      Mulch them deeply and keep filling up the trench and you should get a great number of spears.
      Since you’re in a warm area, you might get two harvests a year – we sometimes do.
      The wet season can be tricky for our asparagus, our annual rainfall is almost 100″ and not all my asparagus are raised. I’ve been trying to move the ‘low liers’ to higher ground but transplanting is not a successful venture for asparagus. They hate moving.
      I’m about to plant another 50 seeds, counting on a 50% germination rate, to add 25 plants to my arsenal. Besides being one of my favorite vegetables, they’re great to can so you can’t really have too many, in my opinion 😀
      I’d love to hear how your plants progress and what your harvest will be like next year!

      1. I forgot to ask whether you’re growing comfrey as a companion plant for your asparagus? If you aren’t, I highly recommend you do. Comfrey and asparagus is a match made in heaven. You can cut the comfrey every year (sometimes twice a year!) for free mulch that’s high in nitrogen – a must for asparagus.
        Good luck!

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