How To Successfully Cultivate Asparagus Garden

Asparagus is among the few perennial vegetables that are typically planted in gardens. It’s a perennial crop that is fairly easy to grow, but patience is needed when growing asparagus since you need to wait up to three years after planting for your first crop.

However, the asparagus plant is worth the wait. The fact that it’s a perennial means that after the heavy labour, your asparagus will crop up year after year. Winter is the season to plant asparagus crowns, which are the roots and rhizomes of a year-old plant.

If you want to learn how to cultivate asparagus, here’s everything you must know regarding the plant. This thorough asparagus guide will lay out every step, from planting to harvest.

About Asparagus

Asparagus has been regarded as a spring garden delicacy and among the locally grown produces you can find in Canada, emerging through the soil in early May.

Asparagus spears, cut when 15-18 cm high, are enjoyed as cooked or raw food. They are flavourful, crisp, and tender. Spears are the succulent young shoots of the plant with scale-like ends. They spring from underground buds called “crowns.” If left to grow, they produce leaves and are called “ferns.”

Green asparagus is the most favoured and the most readily available. White asparagus is the green variety grown without light and doesn’t produce chlorophyll. This is done by piling a soil mound over the emerging spears or covering it with black plastic. The final product is a smooth, thicker, and tender crop than green asparagus.

Purple asparagus produces thicker spears that contain antioxidants, with a peak season from spring through early summer. It is naturally less fibrous and thus more tender than other asparagus types. However, it reverts to green when cooked.

Types of Asparagus

There are various varieties, all with different colours, flavours, textures, and hardiness.
  • Purple Passion – Great for freezing and have a distinctly nutty taste
  • Mary Washington – The most popular variety, along with Martha Washington, because of high tolerance for different growing conditions
  • Jersey Giant – Has a thick stalk that gives it a very meaty and more intense taste
  • Apollo – Produces medium to large diameter spears with slightly tapering spears and tight tips
  • Precoce D’Argenteuil – Has a very sweet taste, with a whitish-green spear and rosy pink tip

When To Plant Asparagus?

A person is harvesting asparagus from a garden.
Asparagus can be grown in early spring when the risk of snow has begun to vanish, and hotter weather is more frequent than long periods of heavy rain. Asparagus season typically begins in early May, but depending on the weather can start in early or late April. It lasts six to eight weeks in which farmers harvest every day. Spears emerge as soil temperatures exceed 50°F in spring.

Some varieties can be planted during early fall while the soil is still warm from the heat of summer. This plant is the earliest vegetable for most gardeners. Enjoy the plant even while or before you’re planting most other crops.

Asparagus beds can be productive for 15 to 20 years, and well-maintained beds are known to produce for 30 years. And because asparagus remains fruitful for ages, it’s essential to plant the best variety for your area.

Should You Grow From Crowns Or Seed?

How To Grow Asparagus From Seed

With their small, early growth, seed crops are challenging to maintain weed-free during the early years. And competing weeds hugely affect crops’ productivity. Asparagus seeds can even be difficult to germinate and are misidentified as weeds when nourishing the beds.

It needs the patience to grow your asparagus patch from seed. Still, there are benefits from the additional wait. You should plant asparagus seeds indoors or in a greenhouse from mid-February to May or 10 to 12 weeks before your area’s last frost date.

Begin by sowing single seeds in seed trays or small posts. Pre-soaking the seeds in lukewarm water for a few hours before planting can expedite germination. Sow asparagus seeds about 1/2 an inch deep in fertile potting soil. Then, place the pots/trays in full sunlight as the seeds require soil temperatures between 70 and 85°F to encourage growth. Dampen the soil every day with a water spray bottle. This step must be fulfilled at the start of spring.

If successful, you should see indications of germination within 2 to 8 weeks.

Transplant plants to the permanent bed when seedlings are 3 inches tall. Plant each seedling about 4 inches deep, with spacings of 12 – 18 inches apart. Cover with a layer of soil and water well.

These perennial plants are either male or female. Male plants usually produce larger and more spears because they don’t need to spend energy on seed production, while female flowers have well-developed, three-lobed pistils. When tiny flowers appear, weed out all female plants.

Let the male plants get some exposure to cold temperatures to become dormant and return stronger the next spring. You can then start regularly harvesting the spears in the third year. Meanwhile, control weeds and insect pests and water the asparagus spears as necessary.

How To Grow Asparagus From Crowns

Planting asparagus with crowns seems appropriate for most home gardeners since they’re immediately available for spring. Plus, they can withstand air exposure and are often a more fruitful option.

Asparagus crowns are the roots of 1 to 2-year-old asparagus plants. They produce edible veggies much faster than seeds due to their advanced growth stage.

So, if you are going with crowns, make sure they are hard and fresh with a faint smell of asparagus. Any wilted and soft crowns with a foul scent are not advisable.

How To Grow Asparagus Plants?

Preparing Your Asparagus Beds

A person wearing white gloves is laying in an asparagus garden.
Asparagus doesn’t go along with weeds, so preparing a deep nursery bed or raised garden box in excellent conditions will be crucial. Opt for a planting area with good drainage, full sun, and relatively free of perennial broadleaf weeds and nutgrass. Consistent soil moisture is vital for growing asparagus for a strong root system and fern growth. Consider starting asparagus in raised beds if a drainage system seems impossible.

Prepare the bed as early as possible. Remove weeds and grasses when preparing the asparagus bed, and continue weeding while the asparagus plants are still young. Asparagus roots create a firmly twisted mat, making removing weeds demanding.

Dig a trench 12 to 18 inches wide and 6 inches deep (8 inches in sandy soil) down the center of the prepared bed. Since asparagus must be planted six to 12 inches below the surface, a shallow asparagus bed will only create problems.

Build mounds down the centre of the trench to bury the crowns. A nice approach is to utilize compost for the mounds, though the garden soil will also suffice. Separate each mound about a 3-inches apart, and it’ll thrive into a lovely thick patch.

Because asparagus live for years on end, amend their field with an abundance of nutrients from the very beginning. Apply 0-20-0 fertilizer (the numbers denote the ratio of nitrogen N, phosphorus P, and potassium K, respectively) at the bottom of the trench and blend it with the topsoil that has been removed. You may also spread organic fertilizer – a layer of bone meal and rock phosphate, a natural mineral powder that stimulates root growth.

Compost is a real champion in helping enhance soil’s fertility and structure. When you incorporate compost and organic matter, allow the soil to sit for a few months to enable the nutrients to penetrate. Till the soil deeply several times before planting so that it will be in fine tilth at the time of planting.

Planting The Asparagus

Soak the crowns in compost tea for 20 minutes before planting. Distribute your asparagus crown along the ridge at roughly 18 inches apart. Spacing is crucial, so make sure you plant the crowns evenly placed. You can measure this distance from the root tip of one crown to the root tip of another. Spread the roots out uniformly so that the outcome will look like a soil-dwelling octopus. Top them with 2 to 3 inches of soil.

Once you finish preparing the trenches and placing the crowns, top-dress them firmly with compost to submerge each crown about 2 inches deep. And then water them.

Adding a light compost or mulch of dried grass clippings will aid in maintaining moisture in the soil, controlling weeds, and even providing some protection against any unforeseen late frosts.

Over time, you will see asparagus shoots appearing. This is when you are needed to add two more inches of topsoil to the trench, leaving a few inches of the shoots exposed above the surface. As the plants grow, add more soil around them gradually until it’s level with the asparagus bed. After filling the trench, the soil should be mounted delicately to prevent standing water around the spears.

Note: Don’t interplant other vegetables in the same bed. Asparagus can’t stand being with other plants.

Caring For Asparagus

Leaving the asparagus spears for the first two years is vital to allow the plant or crown to set itself in the soil.

Mulching & Watering

A garden full of asparagus.
The greatest problem with asparagus is managing weeds during the first couple of years. Weed frequently and carefully — asparagus roots are near the ground and can be harmed by weeding tools. Perennial weeds and grass also go for the essential nutrients in the soil, hampering your young spears. Sadly, beds that permeate with weeds will lead to smaller, less abundant yields.

After clearing any obvious weeds, spread mulch to cover any left weeds. You can mulch with compost, leaves, grass clippings, or straw.

Water often during the first two years after planting. If you live in a dry region, you may want to install drip irrigation or a soaker hose. As asparagus grows, it takes over most weeds and leads long, soft roots deep into the ground, so watering is less necessary. You can decrease the frequency to every two weeks.


Since they are a perennial crop, asparagus plants benefit significantly from increased nutrients in the long run. Like any perennial, they can gradually empty the soil of nutrients as time passes.

Cover the soil yearly with compost to keep the soil rich and help nourish the asparagus plants. Resolve this in early spring before the shoots emerge or during fall after the spears have died back and been clipped to the ground. Asparagus is a heavy feeder, so give plants blood and bone fertilizer in spring and spread composted manure in winter.


Throughout the growing season, asparagus favours a temperature of 70 to 85 °F in the daytime and 60 to 70 °F by night. And then, in the springtime, you shall witness shoots appearing even when the soil temperature reaches 50 °F. Any frost after the shoots start rising will do damage. You may notice poor growth with temperatures exceeding 85 or dropping below 55 °F.

Pests & Diseases

The most prevalent pests on asparagus are the common and spotted asparagus beetles. They appear early to mid-April and feed on spear tips, causing browning and scarring. The pests can be captured by permitting a row or small group of asparagus to grow foliage early in the spring, luring the migrating adult beetles. When a substantial population has plagued these plants, they can be sprayed. Brush the stalk to draw out any larvae or eggs.

Asparagus rust, fusarium crown, and root rot can all be problems. Apply seeds in sterile soil rather than buying plants, and avoid planting new asparagus near the infected site. Rust needs moisture to spread; hence, avoid giving excess water on spears or ferns.

Cultivating ladybugs, hummingbirds, and green lacewings relieve aphids. To spot aphid damage, look for Asparagus growing deformed and misshaped, curled, or yellow leaves. Removing dead ferns can also lessen damage from aphids and diseases. Reap all the spears, so they don’t spread diseases, and observe throughout the off-season for pests or infections.

How To Harvest Asparagus

A person cutting asparagus with a knife in a garden.
The critical point is that you must not harvest asparagus until the third season to harvest. These plants must be allowed to become settled before you can reap manageably. The spears have to mature into ” asparagus ferns,” so the plant has sufficient vegetative growth to hold the energy required to over-winter and beef up.

In the second year, clear away any symptoms of dead ferns. Besides, the crop will need frequent mulching as it will engage in a maturing stage. Some home gardeners usually harvest a handful of spears in the first year; however, it damages the rootings.

The following season you can start harvesting your asparagus for two weeks.

Examine your plant on alternate days for harvest-ready spears. Spears proliferate and may get too woody in a blink of an eye! As soon as an asparagus spear begins to sprout and have leaves, it’s too fibrous for chewing. Harvest spears when the stems are 8 to 10 inches long and between 1/2 and 3/4 inches thick. (Note that thinner spears will be tougher to chew, and thicker spears will have a better texture.)

In early spring, harvest spears every third day; because the weather warms, you might need to reap your crop a couple of times daily. The right time to reap is in the morning when temperatures are still cooler and before they have bathed in the heat and stress of the sun.

Bend the spear sharply and snap it using your thumb and forefinger. You can also wield a sharp knife or scissors, clipping at ground level. While some gardeners like to cut beneath the soil line, be mindful that this could cause unintentional cutting of surfacing shoots nearby if you’re being careless.

Cease harvesting spears if you witness reduced production in your asparagus plants, and the spear’s width is less than pencil size. Allow the remaining stalks to grow to strengthen roots, replenish nutrients, and store energy for next year’s spear production.

How To Store Asparagus

Several jars filled with yellow pickles sitting next to each other in an asparagus garden.
Fresh asparagus is a springtime delicacy that you can eat within hours of harvesting, but it can also preserve for at least a week in the refrigerator.

Soak freshly cut spears in cold water instantly to preserve their sugar content.

To store, wrap the asparagus in wet paper towels and place them in a plastic bag in the crisper drawer. Don’t overcrowd the bags. You can also store asparagus by putting the spears upright in a jar with an inch of water. Cover with a clean plastic bag, securing with a rubber band – allow enough room for air circulation.

Store at about 36°F (2°C) for up to 10 days.

Here is to planting your delectable crop of asparagus in your garden. Just follow the guidelines, and you can enjoy your own veggies in the coming years!

Curb Wise