How to Plant, Grow, and Care For Asparagus in Your Garden
Asparagus is one of the most popular types of vegetables you can plant in your garden, regardless if you are an amateur or an expert. In this article, organic gardening expert Logan Hailey walks you through every detailed step of how to successfully plant, grow, and care for asparagus in your home garden.
As one of the first veggies to welcome in the spring, asparagus is considered a delicacy in many cuisines. Whether served as a grilled appetizer or sauteed side, the young shoots of the plant are tender, nutrient-dense, and versatile in the kitchen.
But you haven’t tasted the true delicious flavor and crisp texture of asparagus until you have picked their spears straight from the garden! Homegrown asparagus beats supermarket-bought every time.
It is also the gift that keeps on giving with minimal maintenance required. Asparagus is a perennial vegetable that you plant once and harvest for up to 30 years! The tasty nutritious sprouts are a nutritious treat every spring and a dazzling foliage display in the summer and fall. You can even grow purple, white, and rosy pink colored asparagus varieties.
If you’ve been wanting to grow asparagus in your garden, there is no better time to start than now! Let’s dig in to how to plant, grow, and care for asparagus that will feed your family for years to come.
- 1 Asparagus Plant Overview
- 2 History and Cultivation
- 3 Propagation
- 4 Planting Asparagus
- 5 How to Grow Asparagus
- 6 Growing White Asparagus
- 7 Pests and Diseases
- 8 Frequently Asked Questions
- 9 Final Thoughts
Asparagus Plant Overview
Plant Type Perennial Vegetable
Species Asparagus officinalis
Hardiness Zone USDA 2-11
Planting Season Spring or Fall
Maintenance Low Upon Establishment
Plant Height Up to 7 feet
Fertility Needs Moderate to Heavy
Temperature 60-80°F is Ideal for Germination
Plant With Best Grown on its Own in Margins
Soil Type Sandy Loam, Well-drained, Fertile
Plant Spacing 12-18 inch Plants, 3-4 feet Rows
Watering Needs Consistent, 1-2 inches per Week
Sun Exposure Full Sun
Lifespan 15 to 30 years
Pests Asparagus Beetle, Japanese Beetle
Diseases Fusarium Wilt, Crown Rot, Root Rot
History and Cultivation
The crunchy tender spring shoots of asparagus have been consumed for thousands of years. In fact, one of the oldest cookbooks in the world features a recipe for cooking asparagus! This ancient vegetable has a fascinating history of culinary, horticultural, and traditional healing uses all over the world.
From Ancient Wild Cure-All to Popular Vegetable
Long before asparagus was a popular dinner plate side, it was collected from the wild to use as a powerful cure-all medicine for everything from toothaches to bee stings to heart conditions and beyond. Ancient Greeks harvested asparagus from swampy wild patches to dry and boil into medicinal preparations.
It wasn’t until the Romans started eating the delicious sprouts as food that asparagus became domesticated and made its way into gardens. As early as 200 BC, the Romans detailed instructions on how to grow asparagus and noted their preference for collecting and planting the seeds of the wild plants.
The Romans valued it so much that they dried the shoots to preserve the nutritious flavorful treat and re-hydrated them by boiling for meals all year round. It is even rumored that Emperor Caesar Augustus was such an asparagus connoisseur that he arranged Fleets of ships to import the most coveted varieties from all over the world.
Asparagus has been consumed in all major European cuisines since the earliest records. It likely made its way to America with the first settlers around 1650 and became integral to Dutch settlers’ gardens. The crop wasn’t grown commercially in the U.S. until the 1860s.
What is Asparagus?
Asparagus is an herbaceous perennial vegetable that can be green, white, purple, or blush pink. It is one of the earliest spring vegetables that sprouts from extensive underground root systems called rhizomes.
It is unusual compared to most other plants we find in the vegetable garden. For one, it is a perennial that will yield for up to 30 years or more under the right conditions. It also has separate male and female plants that need to be grown adjacent to each other in order to produce viable seeds.
When most of us think of asparagus, we imagine the tasty textured shoots used in cooking, however, this is only a small portion of the whole plant. After its initial spring emergence, it grows tall stalks up to 7 feet in height.
These spears grow into flowy gorgeous fronds that later produce little yellow-and-cream flowers which develop into tiny red spherical berries with seeds. Needless to say, asparagus plants in their full glory look absolutely nothing like the vegetable we enjoy on our plates.
Names and Classifications
Asparagus was once considered a member of the lily family, but biologists have determined that it is genetically in its own classification. As a member of the Asparagaceae family, asparagus is more closely related to agave and yucca than it is to turnips or garlic.
Its Latin form Asparagus officinalis is easily recognized in the roots of its common names in modern languages: asperge (Dutch), esparrago (Spanish), spargel (German), asperge (French, and एस्परैगस (esparaigas in Hindi). In some parts of rural England, the word asparagus was corrupted into “sparrow grass,” or simply “grass” amongst some growers in the United States.
Where Does Asparagus Originate?
This universally valued food still grows wild through its native Mediterranean and Asia Minor habitat, as well as in feral patches of riverbanks in Europe and the United States where it has escaped cultivation. Wild asparagus loves moist areas of lakeshores and the margins of wetlands, and can even tolerate the salty soils of seacoasts.
Because asparagus is found growing wild in so many places, scientists have long argued over where it truly originated. It will suffice to say, asparagus has its native roots somewhere around the Mediterranean, Asia Minor, and northern Africa in modern countries of Italy, Greece, Albania, Bulgaria, Turkey, Egypt, and Israel.
While we most commonly eat the young shoots of the plant, asparagus grows up to 7 feet tall with stout stems and feathery foliage. These leaves are botanically cladodes of modified stems that resemble thin needles.
In the late summer, small flowers and eventually red berries develop on the upper portions of the plant. The rhizomatic roots are called “crowns” and readily spread themselves or can be dug up and relocated to establish new patches.
Asparagus can be propagated by seed (the way the Romans did) or by crowns. Crowns are a much more common and successful option that will yield more quickly than planting seeds.
How to Prepare the Planting Area
When propagating asparagus, preparation is the most important step. These plants will grow in place for decades to come, therefore you need to ensure you select the best planting location possible before ever putting a crown in the ground.
Asparagus needs an area with full sunlight and fertile, loose, well-drained soil. It is best to work in large amounts of compost before planting crowns. Compost drastically improves drainage, nutrient absorption, and the overall texture of the soil.
Use a digging fork or broadfork to loosen and aerate the soil, mixing in heaping 5-gallon buckets full of quality aged compost. Be sure that the soil is loose and friable for at least 12-15” deep. The better the soil, the faster your plants will establish and yield. While asparagus is most commonly planted in trenches, raised or mounded beds can also be a viable choice.
This perennial plant will need to grow without disturbance for a long period of time. Do not plant it in the annual garden beds that you hope to grow other vegetables in. Instead, asparagus needs plenty of space to grow and often does best in the margin areas of a garden.
Before planting seeds or crowns, be sure that the area is thoroughly weed-free. Dig up any perennial weeds and use a hoe to remove all annual weed seedlings. Consider mulching with compost over the top of the bed to suppress any new weed growth.
How to Propagate Asparagus by Seed
If you are extra patient, you can definitely grow asparagus from seeds. However, do not expect to harvest those tasty shoots until 3-4 years down the line. The small, fragile early growth of asparagus seeds is what makes them more challenging to propagate.
To grow from seed, begin by sourcing quality organic seeds from a local company or by harvesting the ripe red seed balls from a neighbor’s asparagus patch in the autumn.
Sow the seeds indoors 8 to 12 weeks before your final frost. Soak seeds for at least 24 hours before sowing. Plant seeds in seed starting trays about ¼ inch to ½ inch deep in a high-quality mix. Keep them warm and moist until germination, about 14 to 21 days.
After several weeks, the seedlings should be about 2” tall and ready to transplant into a growing bed. Harden them off in a cold frame or covered porch for about one week before transplanting. Then, you are ready to transplant the seedlings just as you would other vegetables.
If direct sowing, remember that the shoots are very small, which can make them difficult to differentiate from weeds and other plants.
Sow the seeds in the garden when the soil temperatures are at least 60°F. This can be done in late spring or in early fall. Plant them ¾” to 1” deep and firm gently to ensure soil-to-seed contact. Maintain continuous moisture.
You have to keep the tiny shoots totally weed-free for the first few years and, as you’ll see below, weeding is one of the greatest challenges of maintaining an asparagus crop.
Asparagus is a dioecious plant, which means there are actually separate male and female plants (as opposed to squash plants, for example, which have male and female flowers on the same plant). Most commercial hybrid varieties are predominantly male crowns.
Male or Female?
The male plants emerge the earliest and live the longest. They are known to produce the biggest, best spears or shoots for harvesting as vegetables.
Males only provide pollen for the flowers and will not produce the little red berries found on female plants. This means they put most of their energy into root and shoot production, which is why they are the preferred choice for farmers and gardeners.
Female asparagus plants put more energy into producing flowers, fruits, and seeds, which makes them less optimal for spear production. However, they are dazzling as ornamental displays and can still be planted alongside the higher-production male plants.
Keep in mind that female plants can also drop seeds that sprout into new plants, which may cause overcrowding in your asparagus patch. Some gardeners prefer to remove female plants over time to promote the growth of the more robust male plants.
How to Propagate Asparagus by Crowns
Asparagus is fit for a king (or a Roman Emperor), which is why their rhizomes are often called “crowns.” These crowns are one or two-year-old roots that have been pulled from the ground for sale in nurseries and garden stores. Similar to strawberry crowns, these developed roots give you a jump start to establishing your asparagus patch without having to wait for seeds to germinate and establish.
Crowns are very cold hardy and resilient, however, they should still be planted as soon as possible after delivery. They arrive as dormant brown mangily roots that will be planted directly into soil trenches.
How Many Crowns Do I Need?
If you opt for an all-male hybrid variety, 25 plants is usually more than enough for a family of four. 50 plants may be more ideal if you have a standard variety (with some female plants). If you really love asparagus, order 50-75 crowns just to be safe.
Crowns will begin yielding as soon as the first or second year, making them the best option for impatient gardeners. We’ll dig into all the details of how to plant asparagus crowns below!
Plant once and enjoy the harvest for years to come! Because asparagus is a long-lived perennial, you’ll definitely want to be sure you get the planting part right to set you up for a happy asparagus patch that is easy to tend.
Asparagus crowns are best planted with the “trenching” method that buries them deep enough to stay protected from disturbance when you weed, water, or tend the bed. The depth of planting is key to the proper establishment. Crowns exposed to the sun may dry out or get damaged by foot traffic, pests, or weeding tools.
When to Plant Asparagus
Asparagus crowns are usually planted in the spring as soon as the soil can be worked. Many gardeners plant around the same time as they plant their first potatoes of the season. However, asparagus can also be planted in the fall in more mild winter climates.
It’s best to plant crowns as soon as they arrive. If you can’t plant them right away, hold the crowns in a container of moistened sand or peat moss in a cool, dark environment until you are ready to plant. If you have ever planted strawberry crowns, the storage requirements and process are very similar. Do not allow the roots to dry out.
How to Plant Asparagus Crowns
Once you’ve properly prepared an asparagus bed that is out of the way of your annual crops, you are ready to get those crowns in the ground. A couple of hours before planting, soak the crowns in lukewarm water and an optional dash of diluted kelp solution to help rehydrate them. You can also pre-soak in a biologically-rich compost tea for an added boost to the young plants.
While they soak, begin digging trenches about 12 to 18” wide and 6 to 8” deep. If you are planting multiple rows, there should be 2-3 feet between each trench.
Using your hands or a hoe, make a small 2” tall ridge along the center of the trench. Arrange the crowns right in the middle of the mound with their roots draped over the sides and spread out as evenly as possible. They will look like wild little spiders with their roots fanned open in all directions and a little sprouted crown center sticking up in the middle.
Asparagus crowns should be spaced 12 to 18” apart. Measure this space from the root tips, rather than the center of the crown. It is vital to maintain enough space between the crowns to prevent overcrowding and allow space for them to expand their rhizomes as they grow.
Provide at least 2-3 feet between rows to give yourself plenty of room to walk and mow. Some gardeners prefer to make the footpaths the exact width of their lawn mowing equipment (if keeping any grass in the pathways).
Otherwise, mulch the paths heavily with wood chips or decomposed leaves. Be sure that the edge of the bed is marked with soil or a string so that you don’t accidentally mow it down, mulch it over, or step on it.
Once you’ve dug your trenches and arranged the crowns at the proper spacing, it’s time to backfill. You should have asparagus crowns in a trench about 12 to 18” apart with their tops about 2” below the surrounding soil.
Use the soil from digging the trench to gently begin backfilling, being careful not to move or disturb the placement of the crowns. In the first year, the tops of the crowns should wind up about 2” deep below the soil, but they can always be mounded deeper (about 4”) once the first shoots emerge. The mounding will help keep the plants well-drained so they are never sitting in soggy soil.
Crown Planting Recap
This is all a lot simpler than it sounds once you get started. In review, here are the highlights of the crown planting process:
- Soak asparagus crowns for an hour or two before planting
- Prepare trenches 12-18” wide and 6-8” deep
- Create a little ridge in the center
- Arrange the crowns on the mound about 12-18” apart
- Fan out the crown roots
- Backfill the soil so the top of the crown is about 2” below soil level
- Fill in the trench
- Once they sprout a few inches, mound up about 2” more soil (being careful not to totally bury them)
You only have to do this process once and you will reap the benefits for years to come! Once your crowns are planted, it’s only watering, fertilizing, weeding, and harvesting from that point forward.
How to Grow Asparagus
Growing asparagus is super simple once the plants take off. Though they won’t yield for 1 to 3 years, tending these perennial plants is very passive and straightforward. With proper soil prep, you can even automate your irrigation and deeply fertilize just once per season to ensure nearly hands-off management (until it comes time to harvest, of course!)
Asparagus thrives in full, direct sunlight. While asparagus patches are often grown on the margins of the garden (to keep them out-of-the-way of annual crops), it is important they don’t get shaded out by any trees or structures. Partially shaded patches will have lower yields and thinner spears.
Asparagus is fairly thirsty during establishment, but once its roots have dug deep into the soil, they fend quite well on their own. Water very regularly in the first two years, never allowing the soil to totally dry out. About 1 to 2 inches of water per week is ideal for young plants. Older established plants can get by on 1 inch per week of irrigation or rainfall. It is best to use a soaker hose or drip irrigation with a timer to keep your asparagus patch moist.
Mulching is highly recommended for new asparagus patches because it helps conserve moisture and keep the weeds at bay. Consider using straw, compost, aged leaves, or fluffy bark chips loosely spread over your asparagus bed.
The most important consideration with mulching is that it is not so dense that the tender young asparagus shoots have trouble peeking up through it. Avoid using landscape fabric, plastic, or heavy wood chips. You should also definitely avoid any grass clippings or straw that have been treated with herbicides, which will kill your plants and contaminate your organic garden.
The ideal soil for asparagus is deep, aerated, and rich in organic matter. This plant especially thrives in sandy loams. A slightly alkaline pH between 6.5 and 8.0 keeps asparagus happiest. It really does not like excess acidity, therefore you should check the pH of your soil and lime or amend with compost if it is under 6.0.
The soil should be very well-drained and never pool up with any water, as this can lead to rotting the crowns or other disease issues. To ensure proper drainage and depth, consider using a broad fork to prepare your beds. Compacted or heavy clay soils need to be generously amended with compost, peat moss, and/or sand to improve the drainage.
It is also helpful to mulch with compost or weed-free topsoil to keep the weeds at bay. Because this crop spends so much of the season underground, weedy soil is the biggest enemy to asparagus yields.
Climate and Temperature
Asparagus is very hardy and can grow in USDA zones 2 to 11. While China leads the world in production, America produces the bulk of its asparagus in a range of growing zones on both coasts, from Michigan and New Jersey to California and Washington. As you can tell, the plant is very versatile and easy-to-please when it comes to climate.
However, it thrives best in a temperate region. Gardeners in warmer zones should choose a variety that is specifically bred for southern climates. Excessive hot temperatures can definitely impact yields and growth patterns.
The tastiest, most tender asparagus spears come from well-fed plants. This moderate to heavy feeder really appreciates a generous helping of asparagus friendly fertilizer every spring. Lightly top-dress or side-dress asparagus beds (before shoot emergence) with an organic fertilizer that is high in phosphorus, such as fish meal or aged manure. You can also fertilize again in the mid-summer to promote vigorous root development through the rest of the season (though you won’t be harvesting any more shoots until the following year).
Maintaining an asparagus patch is so easy you’ll almost forget to do it. All you need to do is weed and mulch, weed and mulch, every single year! Keep their beds free of weeds and grass to ensure that young spears don’t have a bunch of competition when they are coming up in the spring.
The most important thing to remember about weeding asparagus is that those delicate crowns are just 2-4” beneath the surface. Avoid disturbing crowns with hoes or digging knives. Instead, only shallowly cultivate or use mulches and hand weeding to keep the weed pressure down.
If you prefer blanched white asparagus, you will also need to regularly mound your patch during the shoot phase. Contrary to popular belief, white asparagus is not genetically altered in any way. It is simply buried as it grows so that the green pigments of chlorophyll never establish. The result is white spears that are grown in the dark of the soil. Use a shovel or hoe alongside the bed to raise and mound up asparagus shoots in the spring.
Harvesting asparagus is a bit of an art. It’s typically recommended to avoid harvesting for the first 1-2 years so that your patch can thoroughly establish its roots. Remember that every shoot you take from an asparagus plant in the spring is more energy taken away from the root zone. You want those crowns to have plenty of energy to keep yielding for decades to come.
If you harvest too early, you can kill or drastically weaken the plants. But if you wait to harvest, asparagus will be wildly successful and abundant for years of spring harvests. Patience pays off really well with asparagus!
In the second or third spring after planting, you can begin cutting the spears to grill, saute, or drizzle with butter in your favorite dish. Use garden pruners or simply your fingers to snap the asparagus shoots at the base once they reach about 6 to 10” tall above the soil line. The spears should easily snap at ground level.
You should harvest before any sprouts or flowers open at the tips. The woody nubs of the plant should stay in the ground so that you only take the tender green parts. If you start to notice that shoot production is slowing or the shoots are getting thinner, it’s best to leave the plants until next year.
Stop harvesting asparagus around July 1. The plants need the summer to grow their tall stalks and photosynthesize with their flowy frond-like leaves. Harvesting too late into the season can damage the plants or result in reduced yields the following spring. If you let asparagus shoots grow taller than 10”, simply leave them to develop into stalks that can nourish the growing root system.
Growing White Asparagus
Technically any variety of green asparagus can be grown as white spears. Farmers and gardeners of white asparagus simply hill up a thicker layer of soil or mulch to cover the crowns of the emerging spears in the spring. This prevents sunlight from reaching the asparagus to activate chlorophyll production, leading to a pale white color.
To grow white asparagus, begin hilling any variety as soon as tips emerge in the spring, never allowing them to reach the surface. You will have to dig a bit to harvest the stalks. Keep in mind that this may limit the harvesting window of your crop and result in lower yields, which is why white asparagus can be so much more expensive in stores. This delicacy is sweeter than other types, but can quickly become woody if not picked at the perfect time.
Pests and Diseases
Being a robust wild plant native to moist areas, asparagus is generally a resilient plant. The few bugs and pathogens that do attack these perennial vegetables can be dealt with through a variety of organic means. The best prevention of all asparagus pests and diseases is starting with high-quality, biologically-rich soil that can support the plant’s growth and immune system for years to come.
There are two pesky asparagus beetles (common and spotted) that lay their eggs on young asparagus spears and cause deformed or damaged shoots. The adults are reddish, yellow, or black with stripes or spots. The humpbacked grayish larvae are often found on the ferns or feeding on the red berries later in the season.
Spring monitoring is key to prevention. Use a natural insect soap or diluted neem solution on young shoots that appear to be eaten. Kaolin clay is another great organic option for early spring prevention (the harsh clay particles prevent feeding from beetles). Regular harvesting of shoots reduces the egg-laying sites for the adults. It also helps to maintain a weed-free or low-mulch environment when dealing with these pests.
Japanese beetles are shiny, green-and-bronze flying beetles that attack a variety of over 300 garden crops from potatoes to grass to flowers and beyond. In asparagus, they emerge in late summer and feed on the ferns of asparagus plants, damaging their photosynthetic capacity and potential root development for the following seasons.
Diluted neem oil or dish soap are natural Japanese beetle pesticides that can be applied directly to the leaves of the plant or on the beetles themselves. Scouting is key prevention and they can often be hand plucked and drowned in soapy water. Pheromone traps early in the season may help cut down on populations. It also helps to keep guinea fowl, chickens, or ducks in the yard to keep populations at bay.
Fusarium culmorum is a long-lived fungus that can live in the soil for over 30 years. It is very problematic for asparagus as well as a variety of other plants. Pale red or orange lesions on asparagus stems near the soil surface are the first symptoms of this disease. Eventually, the fungus kills plant stems and spreads with rain or prolonged wet conditions. Harvest damage and damage from pests provide extra wounds for the fungus to enter into the asparagus plant.
To prevent Fusarium wilt, maintain well-drained healthy soil and minimize wounds to the plant as much as possible. Choose resistant varieties, especially if you live in a moist climate. Unfortunately, there are no known cures for this plant disease.
Asparagus rust is extremely common around the world, which is why so many rust-resistant varieties have been developed in recent decades. The fungus, Puccinia asparagi, manifests as rust-colored spores and unsightly brown scales on the stalks.
Infections usually begin in the spring on the previous year’s crop residues, which is why some farmers practice burning of asparagus leaves or otherwise disposing of the residues off the property. It is also important to remove nearby wild or escaped plants that may host the fungus.
It is best to choose rust-resistant varieties and plant asparagus rows in the direction of prevailing winds. Extra spacing may promote better airflow. There is also one organic-approved microbial fungicide called CEASE, which is a biological control that uses bacteria to fight off the fungus.
Crown and Root Rot
Crown and root rot are two of those horrible diseases that can drive farmers out of business. The closely related species Fusarium oxysporum f. Sp. asaparagi and Fusarium proliferatum can live in the soil for 30 years or more. The major symptoms are brown or red lesions in the fleshy roots, crowns, and lower stems. There may also be yellowing in the foliage.
There are no known chemical or organic treatments for the issue, so the only “cure” is to maintain healthy stress-free plants and keep the soil as well-drained as possible. Keep weeds under control and ensure that plants have plenty of water, but avoid waterlogged or poorly drained soil. It is also helpful to maintain a soil pH over 6.0 to protect plant biology from acid-loving fungal pathogens. You should also avoid planting corn nearby.
Frequently Asked Questions
Is asparagus easy to grow?
Once established, asparagus is very easy to grow. This long-lived perennial only needs to be planted once and will yield for years to come. Simply plant asparagus crowns 2-4” deep, 12-18” apart, in trenches 12” apart. Maintain consistent irrigation and ensure that your beds remain thoroughly weeded (but avoid damaging the crowns during cultivation). Asparagus typically begins yielding heavily 2-3 years after planting and can be harvested for up to 30 years!
How long does it take to grow?
Asparagus is a long-lived perennial that takes 2-3 years to establish. If you are starting from seed, the process may take longer, whereas planting 1-or-2-year-old crowns can result in quicker root establishment.
Nothing beats homegrown asparagus spears in early spring. Grill them, slather them in butter, or slice them in a saute for that classic nutty flavor and crisp, crunchy texture. This unique and versatile crop is the perfect addition to any garden margin or perennial edible landscape. The relatively small amount of time required to plant an asparagus plant is an incredible investment for decades of delicious shoots to come.