Fresh asparagus sprigs growing in the garden

Fresh asparagus is a spring delicacy, especially when it comes from your own garden. It is also an easy crop to grow in eastern North Carolina. Because asparagus is a perennial plant that comes back from the roots year after year, gardeners who plant an asparagus patch now can expect to harvest from it for at least 10 to 15 years.

Understanding Asparagus

Because it is a perennial, extra effort must be taken to get asparagus plants off to a good start, to ensure long term productivity. To understand how to grow and care for asparagus there are a couple of terms you need to know. First, the new shoots of asparagus which are harvested to be eaten are known as spears. When spears are left to grow, they develop into tall stems that leaf out with delicate, airy foliage. This growth is known as fern, and asparagus plants produce a lot of fern during the summer, which reaches 4’-5’ tall. The spears and fern grow from the crown of the asparagus plant, the thickened solid mass found just below soil level, from which the roots grow down and the shoots (or spears) grow up.

Asparagus produces separate male and female plants. Male plants are more productive because they don’t waste energy producing seed. When asparagus plants are grown from seed, there is no way to know if the young plants are male or female until they mature. For this reason, asparagus is usually grown from selected ‘all male’ varieties that are propagated by division. Asparagus can be purchased from garden centers or mail order seed suppliers in January and February as dormant plants. They are usually available in packages labeled as asparagus roots or crowns and packed in dry peat moss, rather than as plants growing in pots.

Establishing an Asparagus Patch

The long term health and productivity of an asparagus patch depends on providing plants with good growing conditions in the beginning and caring for them in a way that allows them to build up strong, healthy crowns and root systems. Asparagus plants are best planted in the winter, between mid-January and mid March, while they are dormant. Plants will be most productive when grown in full sun.

Good soil preparation is essential to success. Asparagus grows best in deep soils that have been well amended with compost or aged manure. Good drainage is a must – planting in heavy or wet soils will result in disease problems. Raised beds are excellent for growing asparagus because they increase drainage and are easy to amend.

Acidic soils will require lime applications to raise their pH to between 6.0 and 7.0. Lime will need to be mixed thoroughly into the soil before planting for plants to benefit from its addition. Incorporating lots of compost into the soil will improve plant growth and add nutrients. Asparagus will grow well even in sandy soils when they are heavily amended, and also at the coast since asparagus plants are tolerant of salt spray.

A general guideline for planting asparagus is to plant five plants per asparagus eater in your household. If you plan to freeze lots of asparagus, you may want to increase the number to 10 per person. When purchasing plants, look for one or two year old, all male crowns. ‘Jersey’ varieties are recommended for our area; these include ‘Jersey Giant’, ‘Jersey Knight’, and ‘Jersey Gem’.

A trench method of planting is often used when setting out asparagus. In this method, a trench is dug out 6”-8” deep and 12”-18” wide. Crowns are set out 15”-18” apart in the trench, and are initially covered with 2” of soil. Once the plants begin to grow, another 2” of soil are added. This is continued as the plants grow until the crowns are buried 6” to 8” deep. If more than one row of asparagus is planted make sure to space the rows 4’-5’ apart. Proper spacing reduces disease problems and increases yields.

Keep plants well watered during their first year and mulch to reduce weed problems and conserve moisture. No spears are harvested the first year to allow plants to establish strong root systems. Gardeners can begin harvesting lightly the second year and work up to a six to eight week harvest window by the fourth year after planting.

Learn More

If you have questions about growing vegetables contact your local Cooperative Extension office. In Pender County call 259-1235, Mon – Fri, 8 a.m. and 5 p.m., or visit us online anytime or visit us online anytime at //pender.ces.ncsu.edu/index.php?page=askanexpert

You can also follow us on Facebook