By Melanie Mathieson
The Gardening Guru
Asparagus, one of the most luxurious vegetable, once was cultivated for medicinal purposes as a natural remedy for blood cleansing and diuretic properties.
Then during the Renaissance, asparagus also was promoted as an aphrodisiac and banned from the tables of most nunneries.
Botanically, asparagus is a member of the lily family, closely related to onions and leeks although it bears no resemblance to them in appearance or flavour.
It is a finicky plant, harvested by hand and requiring much attention during the brief growing season. Left to mature, it will sprout into beautiful feathery ferns that often are used in floral arrangements.
Asparagus is a hardy perennial, and is the only common vegetable that grows wild along roadsides and railroad tracks over a large part of the country.
Although establishing a good asparagus bed requires considerable work, your efforts will be rewarded. A well-planned bed can last from 20-30 years.
For this reason, asparagus should be planted at the side or end of the garden, where it will not be disturbed by normal garden cultivation.
Asparagus is one of the first vegetables ready to harvest in the spring. It is native to the Mediterranean and was eaten by the ancient Greeks.
The list of commonly available varieties has changed significantly in recent years. Standard varieties, like Mary Washington, Martha Washington, and Waltham Washington, still are being offered; but a number of new varieties, which either are predominantly or all male, recently have been introduced into common usage.
Asparagus plants are naturally either male or female. The female plants bear seeds, which take considerable energy from the plant and sprout new seedlings, which cause overcrowding in the bed.
Male plants, on the other hand, produce thicker, larger spears because they put no energy into seeds and do not have a weedy seedling problem.
A line that produces only male plants was discovered and has been incorporated into some truly amazing varieties. Jersey Giant, Jersey Knight, Jersey Prince, and Viking KBC are new hybrids with larger yields.
It is advisable to plant the best variety available as an asparagus bed should remain productive for at least 15-20 years. If you are starting a new bed, you may never get to choose a variety again if your bed produces that long.
All the newer varieties are cold tolerant, and also are resistant to rust and fusarium.
Asparagus should be planted as soon as the ground can be worked in the spring. One-year-old crowns or plants are preferred. These young plants should have compact buds in the centre (crown), with numerous dangling, pencil-sized roots when they are ready to plant.
Place the plants (or sprinkle the seeds) in a trench 12-18 inches wide and a full six inches deep. The crowns should be spaced nine-12 inches apart.
Spread the roots out uniformly, with the crown bud side up, in an upright, centered position, slightly higher than the roots. Cover the crown with two inches of soil.
Gradually fill the remaining portion of the trench during the first summer as the plants grow taller. Asparagus has a tendency to “rise” as the plants mature; the crowns gradually growing closer to the soil surface.
Many gardeners apply an additional one-two inches of soil from between the rows in later years.
Adventurous gardeners can start their own plants from seed. Although this adds a few years to the process of establishing the bed, it does ensure fresh plants and the widest possible variety selection.
As asparagus plants grow, they produce a mat of roots that spreads horizontally rather than vertically. In the first year, the top growth is spindly. As the plants become older, the stems become larger in diameter.
Following freezing weather in the fall, the asparagus tops should be removed to decrease the chances of rust disease over-wintering on the foliage.
Because asparagus remains in place for years, advance soil preparation helps increase future production greatly. Working green crops, compost, manure, or other organic materials into the proposed bed well in advance of planting is a good approach.
Asparagus should be fertilized in the same way as the rest of the garden in the first three years. In the spring, apply a good quality fertilizer with a higher concentration of phosphorus (higher middle number) to ensure good growth of the stems and roots.
Starting in the fourth year, apply the same amount of fertilizer but delay application until June or July (immediately after the final harvest). This approach encourages vigorous growth of the “fern,” which produces and stores nutrients in the roots for next year’s production season.
Weeds and grasses are the worst problems for asparagus. They compete with the developing spears, making an unsightly area in the garden and significantly decreasing yield and quality.
Start frequent, light, shallow cultivation early in the spring, in both young plantings and mature patches that are being harvested, in order to reduce and prevent weeds from developing.
Asparagus can be harvested the third year after planting crowns, but for no more than one month the first season. The plant still is expanding its root storage system and excessive removal of spears weakens the plants.
During the fourth year and thereafter, the spears may be harvested. If you planted seeds, you may need to wait up to five or six years before you can begin harvest.
Be aware that pencil thin or thick stems can be equally delicious and contrary to popular belief, thinner stems are not an indication of tenderness.
Thick stems already are thick (often male plants) when they poke their heads out of the soil and thin stems do not get thicker with age. Tenderness, on the other hand, is related to maturity and freshness.
•What causes my asparagus spears to have loose heads?
When the weather turns hot, the growing point expands rapidly and the bracts (modified green leaves) are spread by the early development of the stems and ferns.
The asparagus is safe to eat because only the appearance is affected.
•What causes crooked spears?
Asparagus spears grow quickly and are sensitive to mechanical injury from cultivation or cutting tools, insects, or wind-blown soil particles.
Injured areas grow slowly so that the rapid growth on the opposite side causes spears to curve towards the injured side.
The cause of flattened (faciated) spears is unknown.
Asparagus is low in calories and provides substantial amounts of two antioxidants—vitamin A and C. It truly shines as a source of folate, has a goodly amount of fibre, and is very delicious, as well.
Although it takes a few years to reap the fruits of your labour when establishing an asparagus patch, it is well worth the time and effort down the road as you will enjoy the fresh flavour of asparagus for decades to come.