A native to temperate Europe and Western Asia, asparagus has perennial roots, which sends up each year an erect branching stem several feet in height. One of the most delicate, wholesome and appetizing products of the garden, its new shoots are juicy and succulent both for use as table vegetable and canning purpose.
Varieties: There are few varieties of asparagus in the country: Mary Washington and F1 UC 157 which are of green type, and Argenteuil and F1 Larac which are of white type.
Adaptation: Asparagus grows best in cold places like Baguio and the Mt.Province, and high-elevated areas in Mindanao, like Bukidnon.
Planting and Spacing
Propagation is done through the use of crowns raised from seeds in seedbeds. In small scale planting, crown are raised by hand-drilling seeds in rich, well-prepared seed beds 18 to 30 cm. Apart for commercial production, crowns are produced by drilling seeds with mechanical drillers preferably those that drop one seed in a hill at about 8 cm intervals. The rows may be spaced 120 to 180 cm. apart depending on the tools to be used for cultivation. Asparagus crowns are allowed to grow for one full growing season before being planted in a permanent field or bed.
The crown are dug and lifted out with a short-handed fork, care being taken so as not to injure them. Plant the newly dug crowns as soon as possible since desiccation or drying slows growth.
The depth of planting varies from 15 to 33 cm depending on the physical characteristics of the soil and the products desired. Regardless of the depth of the furrows, the crowns must be placed with the buds up, 5 to 7 cm. deep in the furrows at planting time. Distance of planting varies considerably but the usual practice is planting 60 to 90 cm. apart between plants in the row and 120 to 180 cm. apart between rows.
In deep planting, hilling-up and wider spacing between hills and furrows are given to asparagus raised for bunched stalks.
In the seedling stage, the plants must be kept free from weeds by shallow cultivation. Deep cultivation by hoe is recommended with care being taken not to destroy the roots. In the permanent field or bed, the general care given is much different from that applied to other vegetable crops. The plants stay in the same area for many years.
After the first and succeeding years, it is best to pass the disc and harrow in between the rows before growth begins. The field is kept free from volunteer plant and weeds by proper cultivation.
Irrigation: Moisture is an important factor in the production of shoots; thus irrigation has to be applied liberally during the dry season.
This farm practice is a laudable operation in the management of an asparagus garden for it reduces the cost of cultivation and weeding and it utilizes the wide spaces between the rows of asparagus plants. The intercrops recommended are the bushy legumes such as snap beans, peas, and soybeans; leafy vegetables such as cabbage, lettuce, Pak Choi (petchay) and root crops, such as carrots, radish and sugar beets. The legumes and the leafy vegetables require frequent hoeing and fertilization, which are advantageous to the culture of green asparagus shoots. The practice will produce more robust shoots.
The productive life of asparagus plant depends on greatly on the treatment it receives. An established bed, which receives good cultivation and liberal application each year, may yield profitable from 15 to 20 years. The best amount of fertilizer to use is about 35 tons of compost mixed with 400 kilos of complete fertilizer per hectare. It is suggested that 2/3 of the amount be applied every year before the start of growth or before rainfalls and the remaining 1/3 at the start of the dry season.
Care has to be taken to avoid injury to the crown and other shoots. The knife is inserted outward to cut off the stalk. One thrust with knife is sufficient. The shoots are then washed, bundled and packed before marketing.
Pests and Their Control
So far the only known pest of asparagus in the Philippines is the mealy bug, Ferrisia Virgata Ckll. The bugs feed on the foliage and green portions of the plants, thus rendering them sickly with retarded growth. The control measures are the following :(1) cutting and burning the infested portion, and (2) spraying the plants every two weeks with Sevin at the rate of one or two tablespoonfuls per gallon of water.
Diseases and Their Control
1. Asparagus rust – The diseases is caused by Puccinia asparagi. The typical symptom is the presence of small reddish-yellow spots on the main stem and on branches. As the diseases develops, the spots enlarge into patches until the whole plant becomes reddish-brown or orange and later becomes darker.
Control is by spraying the plants, while still moist with dew, with lime sulfur at the manufacture’s recommended dosage every two weeks. Tropical varieties that are tolerant to asparagus rust are: Mary Washington and Argenteuil.
2. Fusarium wilt – Spears affected with this disease show a brown discoloration of the surface and become stunted and wilted. So far, no effective control has been developed except to avoid planting in infested areas and to use crowns raised on disease-free beds.
Harvesting, Cutting and Storing
The first harvest of asparagus is made at the start of the third season or after the plants have had two full growing seasons in a permanent bed.
Asparagus is harvested everyday during the regular cutting season, which lasts from 8 to 14 weeks. If the weather is too hot, the growth of asparagus is accelerated, thus visiting the field twice is advisable. In cutting asparagus, one hand takes hold of the shoot while the other inserts the knife to the desired depth usually two to five cm. below the soil surface.
sources: Cultural Directions for Phil. Agricultural Crops