As a kid, I really couldn’t stand asparagus. However, in the last few years, we’ve gotten accustomed to the newer varieties, and have learned better how to cook asparagus, this delectable little vegetable has become a mainstay of our household diet. This year, after much research, we decided it was time to undertake growing asparagus in a raised bed in our backyard.
Growing Asparagus In A Raised Bed
Asparagus is a perennial plant that shares many of the same health benefits of onions and garlic. One of the earliest vegetables to emerge in the spring, asparagus is prized for its delicate flavor and diuretic properties. Historical evidence suggests mankind recognized the value of this vegetable early on, and has been cultivating and growing asparagus since the time of the ancient Egyptians.
Being a perennial vegetable, asparagus comes back from an existing root system each year, and can yield a productive crop for over 15 years. However, establishing that root system usually takes several years, and competition from encroaching weeds can take a heavy toll on beds. With this in mind, its important when planting asparagus to give special consideration to soil, light, and drainage requirements, to maximize the crop yield.
Growing asparagus in a raised bed vegetable garden is a straightforward proposition. Asparagus needs well-drained soil, full sun, and must be kept free of competing weeds and grasses. A bit of research shows the best soil mix for planting asparagus is known as a 3-way mix, which is a blend of equal parts well-rotted manure, leaf compost, and sand. The heavy clay soil common to this area demands the soil be amended both for growing, and to promote drainage, so with a plan in place, I started constructing the raised beds in early March, with an eye toward planting crowns in April.
I started by framing 2″ x 6″ lumber into a bed 8-feet long x 4-feet wide. Boards were pre-drilled to avoid end-splitting, screwed together, and the frame set in a position that receives full sun. Once the frame was set, the grass was removed with by use of a hoe, and a series of 8 staggered post-holes were dug using a post-hole digger sized 18-inches in diameter x 3-feet deep. The soil was removed from the holes, and gravel was poured in to a depth of 6-inches.
A call around to the local nurseries looking for 3-way soil mix was less than helpful, but I discovered WKU Farm & Ag Expo Center has a program with the city for disposing of leaves picked up during the curbside leaf collection program. They sell a 3-way mix that was perfect for my needs, which substitutes sawdust for sand. A quick trip there netted me a small truckload (one cubic yard) for a mere $13.00, which is half the price of a load of mulch from the local nurseries.
Once back at the house, the remaining post-holes were filled to ground level with the mix, and the entire area covered with one pound of bone meal, which provides phosphate for strong root development. A one-inch tall mound was built lengthwise using the 3-way soil mix, with a trench along each side of the mound, and the remainder of the raised bed filled a the edges with the soil mix.
Although its possible to establish a bed by planting asparagus seeds, most beds are established from one- or two-year old asparagus plants. We decided to start with two-year old asparagus crowns, and so ordered ten crowns of the Jersey Giant variety from Gurneys. The shipping policy states they ship plants based on growing zone and time of year, which for me would be April.
Right on schedule, plants arrived the first week of April. The crowns were held together with a rubber band and wrapped in a plastic bag. They also included documentation on proper procedures for planting the asparagus crowns, which consists mainly of positioning the crown atop the center mound and draping the roots into the furrow on either side of the mound. Crowns should be placed about 10-inches apart, and a 4-foot wide bed provides only enough room for one row. Soil mix from the edges of the bed was used to backfill and cover the crowns to a depth of 2-inches, and the entire bed watered.
Growing asparagus takes a great deal of patience, since proper establishment of an asparagus bed hinges on root system development, which takes 2-3 years. This year there will be no harvest, as that root system starts to develop. Since we started with 2-year old crowns, I expect my asparagus planting to yield a very small harvest (2-3 spears/plant) next year, with a slightly larger harvest the following year. However, once the bed reaches maturity, each plant is expected to produce 7-9 spears every 2-4 days in the spring. At that point, the beds become relatively self-sufficient, and we should be able to enjoy the benefits of growing asparagus for years to come.