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Growing Asparagus from Crowns & Seeds: Stages with Pictures

You can grow Asparagus either from its Seeds or Crowns. Whichever you go for, there are stages you need to follow in order to get the best results. After planting the asparagus plant, you need to take good care of them. The main caring practices include weed removal, watering, fertilizer application, and disease and pest control.

Facts on Asparagus Growing

Female asparagus produce red berries and small black seeds. Therefore, these female varieties can become weedy. On the other hand, male varieties do not produce berries or seeds but can be grown for spears.

Natural breeding in asparagus is usually by open pollination. This produces both male and female varieties. However, asparagus can also be bred selectively to produce hybrid varieties, which are mostly male.

Ferns
Asparagus ferns harvest

Asparagus crowns are mostly one-year or two-year-old root systems, including roots, rhizomes and buds. Spears grow from buds and are later on harvested. If spears are not harvested they grow into ferns.

What do asparagus spears look like when they start to grow?

With proper care, asparagus can grow from year to year up to ten good productive years and more.

Stages of Growing Asparagus from Crowns

Can you grow asparagus from crowns? Yes. You can either order crowns for growing or raise your own crowns from seed propagation. However, this requires that you should have had at least planned a year prior.

Growing asparagus from crowns means you can harvest them 1 year earlier than growing them from seeds. This is done mostly in fields.

To grow asparagus from crowns these are steps to follow.

Stage 1: Select a Site

Selecting a planting site for planting asparagus crowns is as important as anticipating a high yield. Go for a site that has not grown asparagus before. Why? To avoid instances of crown rot disease from possibly recurring.

Additionally,

  • Go for fertile well-drained, workable soils
  • A site that receives full sunlight of at least up to 6 or more hours
  • Ease of access to water sources especially for sandy soil
  • Avoid light sandy and rocky soils
  • Asparagus does well in less acidic soils with 6.5 –  7 pH

Stage 2: Prepare Your Site

Critical to first growers in field preparation. Unless you have previously planted or have sufficient knowledge of the growth of asparagus in your selected field, you need to fix a few things including:

  • soil pH testing
  • calculate the field size to help estimate the number of asparagus crowns you need
  • incorporate compost manure/organic matter
  • do clean weeding of your field
  • apply lime for acidic soils

You may want to inquire whether your preferred variety of asparagus crowns is available or not.

Stage 3: Ready Your Asparagus Crowns

If you have grown asparagus from seeds, dig up the crowns early (April) from the nursery before buds have just started to emerge.

If you have not grown from seeds, order your preferred variety.

A peanut/potato digger is suitable for lifting off the nursery bed. Keep them cool, preferably about 37 – 38° Fahrenheit. However, avoid freezing them.

Stage 4: Cultivate the Selected Field

Carry out deep plowing 7 – 7/1/4 inches deep. After the topsoils have dried out, do harrowing. Clear the field of any weeds from the previous planting season.

Stage 5: Dig Furrows/Trenches

Prepare trenches/furrows measuring 8 – 10 inches deep by 12 to 16 inches wide for loamy soils with good drainage. For sandy soils, dig 12 – 16 inches deep furrows. And no more than 6 inches deep for clay soils.

Asparagus planting trench
A man demonstrates how to dig out a furrow for planting

Gardeners who are growing asparagus for household consumption can dig 6-inch wide trenches instead of 12 inches. Maintain a 4 inches spacing from each trench.

Stage 6: Plant Your Asparagus Crowns

Carefully inspect each crown before planting in the dug furrows. Apply and mix more well-rot compost. Position them in the trenches 16 inches apart. Spread the roots 2 inches over a soil mound to the bottom of each furrow.

Stage 7: Cover the Crowns Immediately

Cover the crowns immediately after planting to prevent the roots from drying out. Ensure you leave some soil along the sides of the furrows to use in the next step.

Do a good firming in the case of sandy soil. Keep your field watered according to the type and nature of the soil to retain moisture.

Stage 8: Fill Back the Soil

After 3 or so weeks, spears should have emerged. Carefully fill back the soil left along the furrows if the spears have grown 5 inches taller. Continue doing this when new spears emerge until the field soil reaches a uniform level. Take care not to break the fragile ones.

Asparagus Growing from Seeds

Growing asparagus from seeds as a starter is not hard. Though it requires patience.

Preparing asparagus planting seeds is very easy. After you have bought seeds, soak them in water. Allow them to sit in a cool room for 2 to 3 hours.

Follow the steps below if you are growing asparagus from seeds.

Stage 1: Sow Your Seeds

Mature asparagus seed for sowing

If you are starter sowing seeds in pots can be more interesting. Select all-male hybrid variety seeds for sowing. We recommend one seed per pot.

Optionally, sow your seeds in raised wooden 6-inches beds in a greenhouse. Sow seeds individually. Allow each seed enough space for root growth. Wait for the seeds to germinate as this can take from 14 to 21 days.

Keep the soil moist by watering lightly each week.

Stage 2: Harden Your Asparagus Off

Before transplanting, seedlings should be hardened off. To do this, move your potted seedling and raised beds out in the shade first.

Gradually, start exposing them to direct sunlight. Start with early morning hour sunlight to mid-morning.

Stage 3: Transplant The Seedlings

After 10 weeks, your seedlings are developing crowns. Feel and check the roots using a shovel. Hold each seedling by its base and gently uproot them with your hands.

Seedlings can be transplanted when they are 10 – 12 weeks old. Transplant in the spring after the frost is gone. The bottom line, the direct sowing of seeds into the field is highly discouraged. Why? A high percentage of seedlings barely attain plant vigor.

For the transplanting procedure please read the steps from the 5th Stages of Growing Asparagus from Crowns.

How to Care for Asparagus Plant

Throughout its growing cycle, you need to take good care of your asparagus plant. Insects and diseases can invade your planting site or garden and cause damage.

Growth may also be thwarted by weeds. Keeping your established beds weed-free, pest-free and disease-free is indispensable.

Read on to get more information and how-to-care tips.

1. Watering Asparagus Plants

Keep watering your field on weekly basis after growing asparagus from crowns. Watering frequency depends on soil type or season. For example, water three to four times every week for sandy soils if there is little rain.

2. Winter & Frost Care

Hardy asparagus can survive winter. However, young asparagus foliage usually starts yellowing, shriveling, or turning black after frost. Apply an 8-inch layer of mulch to protect crowns from the adverse effects of frost.

Cut each plant leaving a 2-inch stub standing. Do this before the female asparagus has produced red berries.

3. Application of Fertilizers

Applying fertilizers is another care practice. For each plant, apply 2 cups of medium-high organic nitrogen fertilizer in the spring of each year.

Using compost, do side-dressing after each harvesting.

4. Weed Control

You can control weeds with or without applying chemicals. Read on to learn how to control weeds when growing asparagus.

a) Cultivation Only

For the purposes of removing weeds, carry out tillage or hoeing. When is the best time to cultivate?

  • Before the spears appear above the soil level
  • After you have harvested the spears but time before ferns begin to or have emerged

If you have a small home garden of asparagus, hoeing or tilling would be the cheapest, easiest, and most convenient. Alternatively, do simple hand (uprooting) weeding in case of large annual and perennial weeds.

When removing weeds from emerging crowns, change your tillage depth to 2 inches deep at most. Increasing tillage depth any further can easily damage crown roots.

All these cultivation activities would be made easier if you make thorough preparation of your planting site.

Avoid tilling in the spring: not unless you want to want to add fertilizers

b) Application of Mulch

Do light mulching to control weeds in an established asparagus bed in autumn.

To smother weeds in your small backyard garden, use leaves or straw. You can perfectly combine both if want to. You can as well apply compost around each asparagus plant.

c) Use of Herbicide Spray

Spray early in the spring before ferns or pears have formed.

What herbicide can you select? For better weed management and control, the University of Minnesota Extension advises applying pre-emergence herbicide with long, dependable activity. Doing so will reduce early-season weed populations.

Herbicides not only help manage weeds competing with your asparagus for nutrients. They also pave way for minimal soil disturbance.

As it were, follow the manufacturer’s information printed on labels attached to the herbicide container.

d) Grow Cover Crops

If you want to minimize soil disturbance the answer is to plant cover crops. With this control method, you don’t want competition with your asparagus. So selection of cover crop is paramount.

For larger beds, go for fescues, perennial or ryegrass. Plant cover crops in rows and continue uprooting perennial weeds

5. Asparagus Plant Pest Control & Management

Pests feed on ferns and spears hence causing defoliation.

You should be attentive during the growing season when ferns have begun forming. Ultimately, for this to work more effectively ensure you don’t ignore pest control in nearby fields.

Common pests that may invade your asparagus include the asparagus beetle, cutworms, asparagus aphid, and leafhoppers.

Aphids & Leafhopper Management

How can you manage aphids and leafhoppers?

  • Remove the ferns because aphids rely on them only as a food source
  • Foliar application of insecticides

Biological control may also work in some cases but might not be reliable. This natural mechanism involves parasitic wasps that feed on aphids.

Cutworm Control

Cutworms eat the spears and ferns usually at the base of the asparagus. They love coming out at dusk or very late evening hours. To discover them, have a comprehensive monitor of growing spears and ferns.

The best way to control cutworms is to treat soil with herbicide. Ask for a product that matches the description of the cutworm pest/damage you saw. For instance, how they look, their color and the time they are active.

To reduce costs, spray in the winter when the soil is moist. Consequently, this is when more larvae populations are likely to die. Why? They become constant targets of unfavorable cold weather.

During the summer and the spring, you may be required to re-apply herbicides as necessary or if cutworms appear to remain active. Moreover, keep your garden weed-free.

Asparagus Beetle Control

Japanese asparagus adult beetle can damage foliage

Known to habitat the soil, if not controlled, Japanese beetles are very harmful. They emerge mid-summer from the soil as a grub.

They can defoliate asparagus by feeding on the spears, ferns and emerging soft buds.

Asparagus adult beetles on ferns

To help control them:

  • Remove residual ferns present from the previous harvest from your garden and burn them
  • Clear your asparagus site by removing all other possible hiding and hatching spots for beetles e.g. mulch, straw and cover crops
  • Harvest ferns more regularly to discourage new hatches of beetles

Getting rid of these insects can be challenging since they can fly. If beetles continue being a problem, you can resolve organic chemical control. Start with applying neem oil. If there is no change, resort to other insecticides.

We recommend buying those with short harvesting intervals. Why? They won’t interfere with the harvesting of spears.

6. Asparagus Disease Management and Control

If you let diseases invade the asparagus field, yields would decline. Below are the common diseases and how to manage them.

a) Asparagus (Leaf) Rust

Asparagus rust is a fungal disease that can invade your asparagus plant after initial or subsequent spear harvests.

This infection is usually marked by yellow or orange spots on the asparagus stems when an outbreak occurs. Later at the advanced infection stage, small uneven lesions may form on the stems of ferns. The spears may not produce the symptoms.

To manage asparagus rust:

  • Ensure that you harvest spears regularly
  • Plant more resistant varieties of asparagus
  • Remove infected as well as affected ferns

b) Fusarium Stem & Crown Rot

This disease results in poor growth of asparagus. Leaves and stems will begin to grow again, more often than not.

The best way to manage this disease is during site selection and preparation (refer to stages of growing asparagus from crowns above).

More control measures:

  • Select varieties resistant to Fusarium including Jersey Giant, Jersey Knight or Jersey Supreme
  • Practice crop rotation: allow a 5-year gap for the asparagus plant
  • Avoid planting your crowns at greater depths
  • Deal with Magnesium and Manganese mineral soil deficiencies
  • *Soil fumigation to reduce the population of the fungus. Note: Fumigate soil when all the other measures have not worked.

Other disease problems that need attention include cercospora leaf spot, phytophthora root rot and purple spot.

FAQs on Stages of Growing Asparagus

Q: How long does it take to grow asparagus from seed?

Answer: If you started sowing seeds in raised beds, it could take at least three years to reach the harvesting stage.

Q: Why should I soak asparagus seeds before planting?

Answer: To soften the hard seed coat and facilitate germination.

Q: How long does it take to grow asparagus from crowns?

Answer: Growing asparagus from crowns can take at least two years to reach the harvesting stage.

Q: Where can you get asparagus crowns?

Answer: You can purchase from a reputable commercial nursery near you. Purchasing 1-year old crowns for purposes of planting is the best.

Q: Where can I get asparagus seeds for sowing?

Answer: Buy from reputed commercial nursery tree growers, suppliers or sellers near you. Gardeners can harvest and prepare seeds from mature berries.

Q: How fast do asparagus spears grow?

Answer: The spears of asparagus plant can grow 1 - 2 inches per day after they emerge.

Why Start Asparagus Growing?

Why should you start growing asparagus? This perennial vegetable native to European coastal regions can now be grown in many parts of the world.

Gardeners grow them mainly for nutritional value and health benefits. Besides that, you can grow them on a commercial scale. This will be a long-term investment alternative to serve your financial needs for up to a decade.

Sources & References

  1. Planting asparagus. University of Minnesota Extension. https://extension.umn.edu/growing-guides/planting-asparagus. Accessed online 25th August 2021
  2. Specialty Crop Profile: Asparagus. Anthony Bratsch, Extension Specialist, Vegetables and Small Fruit. https://vtechworks.lib.vt.edu/bitstream/handle/10919/55167/438-102.pdf?sequence=1. Accessed online 24 Aug 2021
  3. University of Maryland. Asparagus. https://extension.umd.edu/resource/asparagus. Accessed online 26th August 2021

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