Perennial plants die back in the winter and come back in the spring from the same root system, and they can live for many growing seasons. Asparagus plants will produce for 20 years, if not longer, providing the tender green spears every spring. It will take two to three years before the asparagus reaches full production. So before you begin planting, choose the perfect site and prepare the bed well — it’s going to be there a long time.
Asparagus, like most vegetable plants, needs full sun, meaning at least six to eight hours of uninterrupted sunlight every day. Asparagus beds planted near trees may receive full sun at the time the bed was prepared, but remember that trees grow. Years from now the bed may become shaded, so plan accordingly. Asparagus beds can be established in the vegetable garden, but consider preparing the bed along the garden’s edge. That way any equipment used in the garden will not disturb the bed.
Good soil preparation is a must. Before planting — or even thinking about buying asparagus to plant — work on the future site of the asparagus bed. First, perform a soil test. Asparagus prefers a soil pH of 6.0 to 6.5 and will not grow well in very acidic soils. A soil test will also tell you which fertilizers are best for asparagus grown in that spot. If possible, choose a site free of perennial weeds. If this is not possible, make sure all weeds are gone by planting time. You can use the herbicide glyphosate or remove them by hand.
Asparagus spears emerge from the ground, therefore, a well-drained soil is crucial. In heavy clay soil, amending is a necessity. Turn in plenty of organic matter such as straw and leaf mold, compost kitchen waste, animal manures and peat. You may find you have to add organic matter several times to improve the health of the soil before planting time.
Plant during the dormant season. Dormant asparagus crowns can be planted as early as January in south Alabama through March in north Alabama. A crown is the root system of an asparagus plant that was grown from seed. Use 1-year-old crowns or plants because it takes one to two years longer to produce asparagus from seed.
Asparagus should be planted in a trench or furrow. Dig a trench about 8-12 inches deep and just as wide. Lay the crowns in the bottom of the furrow about 12 inches apart with the roots spread apart and the bud pointing up. If more than one row or furrow is made, space them about 5 feet apart. Cover the crowns with 2 inches of well-amended organic soil. You will soon see the asparagus plant popping up through the soil. When you do, add a little more organic soil. Keep doing this as the asparagus plant grows until the furrow is filled.
Asparagus is a fern-like plant. Let it grow until frost turns the plant brown, at which time you can cut the brown ferns down. Early the next year, use your soil test results to fertilize the plants.
Early in the year, you will see the asparagus spears start to poke through the ground. But be patient. Do not harvest any asparagus the first year. Much like blueberries, harvesting too much, too early will result in a weak plant. The second year you will be able to enjoy about six weeks of harvest, and maybe eight weeks the next year.
There are several varieties of asparagus from which to choose. Most people have heard of Mary Washington, an older, female variety that has been a standard for decades. I really like some of the newer male hybrids such as Jersey Knight and Jersey Gem. No, you do not need more than one variety, and it doesn’t matter if you have male or female plants. Male plants often produce more spears and they do not produce seeds like the females do, which can lead to seedling asparagus that may become a nuisance in the garden. There is also a purple cultivar of asparagus that grows well here, Purple Passion. Once cooked, it will turn green.
Green, purple, blue or yellow, fresh asparagus spears from the garden are hard to beat. Right now is the best time to start preparation of the beds, so go get busy.