By Sherry Stover
VCE Southside Master Gardener
There is simply nothing that compares to the fresh taste of home grown asparagus, Asparagus officinalis. And growing your own asparagus is easy. Even better, asparagus is a perennial. And once established, the crowns will continue to provide a delicious crop for 20 years or more.
: The frilly foliage of the asparagus plant make it attractive in the garden even after harvest is completed.
Preparing The Planting Space (Bed)
Asparagus performs best in a sunny location that receives at least 8 hours of full sun. It needs to be loose, fertile soil with a pH of 7.0 that drains well and the beds need to be filled with nutrients from the start, by working in generous amounts of compost before planting. Soil testing and bed preparation should be completed in the season prior to planting. Your local County Extension Office can provide soil test kits for you to send to the Soil Testing Lab in Blacksburg.
Growing Crowns or Seeds?
Asparagus can be grown from seeds or crowns. Crowns are the roots of 1 to 2 year-old asparagus. They produce an edible crop much quicker than seeds. Seed crops need to be started indoors 12 to 14 weeks prior to planting in your garden. As they are small they need time to develop crowns and they are more difficult to keep weed-free during the early years. If you opt to plant asparagus crowns it is good to select varieties that are rust resistant like the Mary Washington and the Jersey varieties. Also look for crowns that are a “grayish-brown color, plump and healthy-looking”.
Selecting Your Plants
Asparagus plants are either male or female. Male plants tend to grow larger and have higher spear production levels. There are many different varieties on the market, including green, purple and white varieties. Female asparagus plants will produce berries late in the year. This takes a lot of energy from the plants, resulting in smaller spears the following year. Mary Washington, Jersey Giant, Jersey Knight and Purple Passion are good varieties to choose from.
The number of crowns needed will be based on how many people will be fed out of the asparagus bed. Ten to 12 crowns will feed a family of four. Unless you love them as I do. I planted 12 crowns for just me and I freeze and can them so they last me almost all year.
Planting is best done using the trench method. To plant, begin to till or break up the area that has been chosen for the bed. Dig trench rows 14 to 16 inches deep and 12 inches between rows. Add compost, soil and fertilizer based on the soil sample. Fill in the trenches until it is 6 to 8 inches deep, then place the asparagus crowns in the trenches 12 to 14 inches apart and 12 inches between rows. Finish by filling in the trenches with a compost and soil mix. Add 3 to 4 inches of mulch to help keep the asparagus warm and to help conserve soil moisture and reduce the amount of weeds. The best mulch is one that will break down and add organic matter back in to the soil.
Do not harvest any the first growing season. The plants need a few years to grow and spread. You can harvest a few spears in the second year, about half the in the third year after that, and then all of the asparagus every spring after that. The plants do multiply but not invasively. Harvest by bending spears over until they snap, or cut just below soil surface. Stop harvesting when spears are less than pencil-size. You can store harvested spears upright in the refrigerator for up to 2 weeks.
Fall mulching helps protect the sensitive crowns from low temperatures, heavy rainfall and frost over the winter. Wet, cold soil can cause the roots to rot. After the first frost, or, if your area doesn't experience frost, when the ferns turn yellow, prune them to 2 inch stubs. Cover the bed with the cut off stems and seeds so that the seeds go into your bed so they can multiple. Once the stems have been cut back, stop watering the asparagus entirely. Spread 4-6 inches of mulch such as straw, wood chips, or other organic materials over the crowns. Remove the mulch in the spring after last frost and as the shoots begin to emerge.
You can mulch year round to keep the beds weed free. If so use a mulch that the spears can push through as they grow. A two to four inch layer of shredded leaves or two inches of straw helps keep the beds weed free.
My favorite roasted asparagus recipe.
Tuscan style roasted asparagus
Prep: 20 min. Bake: 15 min. Makes: 8 servings
1-1/2 pounds fresh asparagus, trimmed
1-1/2 cups grape tomatoes, halved
3 tablespoons olive oil, divided
2 garlic cloves, minced
1 teaspoon kosher salt
1/2 teaspoon pepper
1 tablespoon lemon juice
1/3 cup grated Parmesan cheese
Preheat oven to 400°. Place the asparagus, tomatoes on a foil-lined 15x10x1-inch baking pan. Mix 2 tablespoons oil, garlic, salt and pepper; add to asparagus and toss to coat.
Bake 15-20 minutes or just until asparagus is tender. Drizzle with remaining oil and the lemon juice; sprinkle with cheese. Toss to combine.
1 serving: 95 calories, 8g fat (2g saturated fat), 3mg cholesterol, 294mg sodium, 4g carbohydrate (2g sugars, 1g fiber), 3g protein. Diabetic Exchanges: 1-1/2 fat, 1 vegetable.
While we are all still practicing ‘social distancing’ due to COVID-19, and all Halifax County buildings remain closed to the public, if you have gardening questions, you can best reach an Extension Master Gardener or Extension staff member by sending an email to firstname.lastname@example.org. If you can’t email, you can call and leave a message at the Extension Master Gardener Help Desk at 434-830-3383, giving us your name, telephone number, and nature of the call. The Help Desk phone is checked timely and someone will get back to you, although it may be from a different telephone number. Keep washing your hands, wear your mask and consider planting some asparagus for a wonderful springtime treat.