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How to Harvest and Grow Asparagus [Complete Growing Guide]

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. 

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

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, and they’re really nice-tasting. (Where to buy Mary Washington asparagus plants and seeds)

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.

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.

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.

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.

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.

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.

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.

Where to Buy Asparagus Crowns, Plants, and Seeds

UC 157 F2 Asparagus Garden Seeds – Non-GMO, Hybrid. Perennial. Developed by Frank Takatori and Frank Southers at the Unive… [More] Price: $5.48 – Buy Now

 Wondering where to buy asparagus plants and seeds?

  • Eden Brothers sell Mary Washington asparagus seeds. The most well-known, classic asparagus variety.
  • True Leaf Market sells UC 157 F2 asparagus seeds. Despite the unappealing name, this is one of the best varieties of asparagus with heavy yields of dark green asparagus spears. It’s a great choice for your veggie garden and market gardeners.
  • Nature Hills Nursery has several varieties of asparagus plants for sale, including Jersey Knight (extremely vigorous and grows well in just about any soil, even heavy clay! Grows big, juicy spears in early spring; one of the first vegetables you can harvest each year), Purple Passion (heavy crops of purple to blue-greenish spears. Lovely texture without the stringy bits.), and Mary Washington (one of the most popular heirloom varieties with a heavy yield. Thick stalks that bunch close together).
  • Amazon offers a wide range of asparagus seeds and crowns from different sellers.
  • Tractor Supply offers asparagus seeds, including Purple Passion, Jersey Knight, and Mary Washington.

If you’re wondering how to start a vegetable garden, don’t miss our complete guide to starting a vegetable garden from scratch!

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!

Author

  • Elle

    Jack of all trades, master of some. Wild garden grower. Loves creating stuff. From food forests and survival gardens to soap and yoghurt. A girl on a farm with two kids and one husband (yep, just one - although another one would be handy). Weirdly enjoys fixing fences and digging holes. Qualified permaculture teacher and garden go-to.

James

Sunday 21st of August 2022

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?

Elle

Monday 22nd of August 2022

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 :D I'd love to hear how your plants progress and what your harvest will be like next year!

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