Planting Asparagus Crowns: 9 Pro Tips
Asparagus spears are one of the first perennial vegetables to emerge in spring. With crowns, you can skip the lengthy seed-starting process and have edible spears in less than a year. Seasoned grower Jerad Bryant shares these nine pro tips for easy asparagus growing, no matter where you live!
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Perennial vegetables are perfect for lazy gardeners. Rather than starting seeds and transplanting seedlings annually, you’ll plant crowns once and have edible asparagus for 15 years or more! Because this crop lives a long life, it’s best to give it a proper planting to set it up for success.
It’s important to prepare the site well before planting asparagus. These crops prefer loose, fertile soil with adequate drainage and a pH between 6.5 and 7.0. Their roots may reach 10 to 15 feet deep! Avoid planting them in containers, and give them space to spread up and out.
When you give your plants what they need, they’ll reward you with delicious, crunchy, and nutritious spears. Follow these nine expert tips to successfully plant crowns, and you’ll have fresh asparagus ready for harvest in no time!
Prepare the Site
The first step in planting is to prepare the site well. This vegetable needs loose, fertile soil. A loamy mix with equal parts sand, silt, and clay works well. Other options include potting soil, raised bed mixes, and compost.
If your garden has loamy or sandy clay, amend it with compost. Compost creates the ideal environment for the roots, inoculating the dirt with beneficial microbes and introducing plant nutrients that asparagus needs to thrive. Aim to amend the area with compost a few weeks before planting. If you miss the chance and are planting now, simply amend the area while you plant.
If you lack compost, adding some organic fertilizer in fall or late winter benefits new specimens. Use a soil test to determine the garden’s nutrient levels, then fertilize accordingly. Asparagus appreciates equal amounts of the three primary nutrients; choose one with a formulation like 10-10-10, which contains 10% nitrogen, 10% phosphorus, and 10% potassium.
Because of their deep-reaching roots, the crowns struggle in shallow areas or spots with standing water. Choose a site in full sun with good drainage, regular airflow, and no weeds. Avoid areas prone to frost, as late spring freezes can harm the emerging spears.
Choose a Cultivar
Asparagus crowns are dioecious, meaning they have male and female flowers on separate plants. Cultivars are either male or female—male ones produce pollen while female ones form red berries with seeds. Both produce edible stems, though males sprout many thin ones while females grow a few thick ones.
Many varieties offer purple, green, or white spears with different shapes and textures. ‘Purple Passion’ is a lovely type with black-purple spears that are thick, round, and perky. They’re perfect for adding color to roasts, sautés, and steamed veggie medleys.
If you live in a cold area with recurring winter frosts, you should choose a hardy, frost-tolerant variety—any cultivar in the ‘Jersey’ series is perfect for cold areas. A new cultivar ‘Millenium’ is a reliable choice for beginner growers.
Find Healthy Crowns
Crowns are often available at plant nurseries, farmers’ markets, and online shops. Only purchase certified pest and disease-free crowns from a reputable source. Some pathogens and insects can overwinter on bare-root specimens, entering your garden when you plant them. Avoid this issue by asking the plant shop if the plants are certified pest and pathogen-free.
Healthy crowns will have plenty of roots sprouting below the top of the plant. They should feel thick, perky, and turgid. Avoid buying them if they look unhealthy and lack sufficient root systems. If you purchased plants online that came in poor quality, contact the seller to let them know the situation.
Maintain Consistent Moisture
The best time for planting asparagus is early spring before the crowns awaken from dormancy. Get the plants in the ground as soon as the soil is workable. They’ll sprout new roots, form shoots, and push out of the ground as days lengthen and warm in spring.
If it’s too early for planting and the ground is still frozen or soggy, you may wait to plant for a week or two. During this time it’s best to keep the roots moisturized and healthy. Soak them in water, remove them, and wrap them in moist moss or plastic wrap. Then, place the crowns in a cool, dark location for less than two weeks.
Dig Trenches
It’s time to dig! Trenches are the best way to plant this vegetable, especially if you have multiple crowns. Start by digging a trench a foot wide and deep; if you’re planting many crowns, give each one a foot of space. If you have five crowns, the trench should be five feet long.
Shift the planting depth for clay or sandy sites. In soils with heavy clay, dig trenches six to eight inches deep. In sandy sites, dig trenches 10 to 12 inches deep. This helps the plants adapt, no matter how poor or rich the dirt is.
Rather than a few long trenches, you can also opt for many short ones. This is ideal for small gardens with short beds. Dig at the same depth, and space trenches three feet apart to accommodate future growth.
Evenly Distribute
With ready trenches, it’s time to place the asparagus plants in their new homes. Ensure the roots point downward and the crowns point up; new growth emerges from the tops, so it’s important to have them pointing upwards.
After placing the asparagus down, splay their roots out so they fill the trenches. In trenches with multiple plants, arrange each so the buds of one touch the root tips of the next. They’ll look like a line of octopuses when you’re finished!
Even distribution is key. Ensure no two plants overlap, and grant them sufficient space width and lengthwise.
Fill Up Trenches
With the soil you dug earlier, backfill the trenches with two to three inches of dirt. Don’t fill them up just yet! It’s best to let asparagus grow first before adding more. Too much soil on top can cause rot, sogginess, and excessive pressure.
Water the site well after backfilling, making it as moist as a wrung-out sponge. The spears should pop up in a few weeks. Some may take longer than others; avoid messing with or digging them up, as their tender roots are sensitive.
After the spears emerge, you may continue filling the site so dirt reaches the soil level. Some growers continue mounding soil around the spears, creating small hills. These mounding hills provide cold and heat protection during summer and winter. Though they’re not necessary for asparagus growing, they’re incredibly helpful.
Wait to Harvest
It’s best to wait to harvest young plants. After planting, asparagus crowns spend their first year growing new roots and shoots to gather energy for next year. Rather than harvesting after planting, you should wait until the second spring to cut them down.
In the second year, harvest spears for two weeks in early spring. Avoid cutting the plants down for the rest of spring and summer, as they’ll grow weakly next year. This veggie is similar to bulbs like daffodils and tulips—it uses this year’s growth to gather energy for the next growing season.
The third year after planting, you may harvest as many spears as you’d like until around July 1st. Harvest them with a sharp knife, slicing their stalks close to the ground. Let the stalks grow tall and woody after July. They’ll sprout fern-like fronds that photosynthesize, preparing sugars and energy they’ll store in their roots.
Add Fertilizer or Compost
As the specimens age and mature, they’ll use up nutrients from the soil. They need extra nutrients about once every three years in areas with fertile soil. If fertility is lacking, they may require more frequent fertilizing.
Rather than fertilizing with synthetic types, try using compost! It’s a valuable soil amendment that you can easily make at home. It adds nutrients as fertilizer does. It also boosts structure, absorbency, and microbial presence. Add it each year in the spring before the spears emerge, spreading a two to three-inch thick layer on top of the dirt.
