||Asparagus officinalis L.
- Asparagus is an herbaceous perennial and is grown in large areas in countries like USA, Germany, Spain and France, while India’s contribution is meager.
- The tender shoots called ‘spears’ are used as vegetable and in preparation of soup.
- It is also eaten as salad.
- The canned and frozen spears are also used as processed foods.
- The tender shoots contain a white crystalline substance, asparagine, which is used in medicine as diuretic in cardiac dropsy and chronic gout.
- It has good potential as fresh vegetable.
- Asparagus has been grown for many years.
- The Ancient Greeks and Romans relished this crop.
- It originated in Asia Minor and is a member of the lily family.
- California, Michigan, and Washington are the major producing states, but there is some commercial production in many of the northern and western states.
- Warm regions such as Northern Mexico and Southern California also grow it.
- Recent research has shown that asparagus can be grown at a profit in India too.
NUTRITIVE VALUE (per 100 g of edible portion)
|| Fat (g)
|Vit. B2 (mg)
|Vitamin C (mg)
- Asparagus is grown in temperate and sub-tropical regions.
- Mean day temperature of 25-30oC and 15-20oC at night are ideal.
SOILS AND SOIL PREPARATION
- Well drained soils are must for successful production, and sandy soils are also preferred.
- Good drainage is important to control crown rot disease.
- Commercial plantings of asparagus should not be made in soil that is heavier than a sandy loam.
- Avoid sites which retain standing water for more than 8 hours after a heavy rain.
- The optimum pH is 6.5-7.5.
- With green coloured spears : more popular and mainly used in fresh market
- With white or light green coloured asparagus - mainly used for processing.
- All available male hybrids are more productive and do not produce seed which sprouts to become a weed.
- Jersey Gem, Jersey Giant and Greenwich produce superior yields in North Carolina.
- Jersey Gem has the added benefit of having tolerance to the disease Cercospora leaf spot.
- The increased yields of hybrids make them worth the extra seed cost.
- Recommended by IARI, New Delhi.
- It is an early, uniform, productive variety, delicious with high food value.
- The spears are large, green, succulent and light tipped.
- Average yield is 80-100 q/ha.
- Bush type, medium, uniform plants and productive.
- The spears are 15-20 cm long, succulent, tender, green with better flavour and suitable for soup preparation.
- Yield is 90-110q green spears/ha.
- Despite these varieties, UC-72, UC-66 and Sel-831 are also grown in Kashmir, India.
- In hills : March-May
- In plains : July-November
- Asparagus can be propagated through seeds, seedlings and crowns but most commonly followed practice is through seeds only.
- It requires about 3-4 kg seed for cultivation in one hectare.
- Apply chicken manure @75-125 quintals per hectare or Farm Yard Manure@150 to 250 quintals per hectare as basal dose.
- In addition, during succeeding years, apply 80-120kg of nitrogen, 80-100kg of phosphorus and 60-80kg of potassium per hectare twice in a year.
- Make one application of N, P and K just before first appearance of spears in the spring in early March.
- Apply the same amount of fertilizer at the conclusion of the harvest season in mid-May.
- Apply the fertilizer to the top of the soil or with very shallow incorporation.
There are three methods of planting
a) Crown planting
- Use only certified crowns for planting as they may carry several diseases
- Plant asparagus crowns (roots plus plant buds) so that the top of the crown is 15 cm below the soil level.
- Depth of planting is critical, if planted too shallow, asparagus will produce a large number of small spears that are not commercially salable.
- If planted too deep, spears will be very large, but will be few in number.
- Plant crowns 30 cm apart in the row with the buds upright, and 150 cm between rows to have 21,750 crowns per hectare.
- Cover crowns with 5-7.5 cm of soil after planting.
- As plants grow, gradually fill in the rest of the furrow with 2.5-5 cm of soil in 3-5 cultivations, but do not completely cover plants.
- The furrow should be completely filled by July of the first year.
- Plant before the buds begins to appear in the spring.
- Both direct seeded and transplanted asparagus can be planted in single or double rows with 5 foot spacing between beds.
- Single rows should be planted on top of "W" shaped beds (Fig.15.1).
- The "W" shaped rows are formed with a wide furrow opener followed by a beds shaper.
- Double rows of direct seeded or transplanted asparagus should be planted on shelved beds (Fig. 15.2).
- Transplants can also be planted on the side of an angle-shaped furrow (Fig. 15.3). The "V" shape in the middle of the row is important since it provides a place for soil washed from the side of the beds during rains (Fig. 15.4).
b) Direct seeding methods
- Seeds should be placed 5 cm apart in the row, 2 to 2.5 cm deep.
- Single row seedlings require 2.5-3.4kg of seed per hectare and double row seeding require 4.5 to 6.8 kg seeds per hectare.
- Asparagus seeds germinate best at 24°C.
- Direct seeding is preferred when the soil temperature is at least 16°C.
c) Seedling transplant method
- Asparagus seedlings can be grown successfully in peat pots, plastic pots, trays, peat pellets or seedling type trays.
- Seedling growth and survival are usually better with larger cells up to 5x5 cm seedling cells.
- Most of the artificial soil media produce a good transplant.
- Good growth above the crown and good root system development require planting the seed not more than 1.25 cm deep.
- Transplanting of seedling is preferred after the threat of frost but before temperatures get above 32°C.
- Favourable conditions usually occur in April and May.
- Direct seeding have the following advantages over crown planting:
- Reduced costs, mechanization of planting, freedom from disease and increased yields are few advantages of this method.
- But these methods require more care, closer attention, irrigation and better management than crown planting.
USE OF PLANT GROWTH REGULATORS
- Abscissic acid appears to promote sink strength or encourage phloem uploading.
- Gibberellic Acid promotes growth of asparagus buds.
- Butyric Acid supports spear emergence.
- Adequate moisture should be maintained for good germination and early seedling growth.
- Do not let asparagus plants become dry while they are establishing a root system during the first two months.
- Water stress during this early stage can reduce yields.
- After the root system is established, irrigation is needed only during extreme drought.
- Weed control in asparagus production is very important.
- Timely cultivation is a critical part of any asparagus weed control program, especially during the first two years.
- The first year asparagus should be cultivated at least once in a month until September or 6 times.
- The number of cultivations may be reduced by using herbicides.
- Remove all weeds that are present after harvest.
- Use only very shallow disking (2.5 to 5 cm) to remove these weeds.
- Deeper disking will damage crowns and can drastically reduce yield.
- Asparagus can be harvested on limited basis (2 to 3 weeks, or 8 spears per plant) during the first year after planting.
- Harvesting should be limited during the second year as it results in slight reduction in spear size which is as an indication of when to stop.
- It takes a long time for asparagus to develop a large root system.
- A large root system is necessary for a healthy bed of asparagus to produce for many years.
- Do not harvest too much in early years because bed life can be shortened and total yield and profit drastically reduced.
- Harvest 6 to 8 weeks during the third year of growth, generally until mid-May.
- Allow spears to reach 20 cm tall and then cut with a knife or hand snap at the soil surface.
- Spears should not be allowed to get taller than 22.5 cm.
- The decision on when to harvest is based on having an average of one harvestable size spear per foot of row.
- When temperature exceeds 27°C, it may be necessary to harvest daily.
- Mounding the soil to a height of 25-30 cm over the rows is practiced to blanch the young spears and get ‘white asparagus’ for canning.
- After harvest, the spears should be held in a cool shaded place and sprinkled with water to prevent shriveling and wilting.
- A single irrigation sprinkler over the boxes works well. Asparagus should be hydro cooled before packing.
- When preparing asparagus for market, spears should be uniform in length.
- Tie in bunches of 500-1000g or pack loose in a carton.
- Asparagus loses edible quality rapidly and should be cooled as soon as possible.
- After bunching, place the butts of the spears in damp peat moss or blotter paper in a crate or carton.
- Pack 6.8 or 13.6 kg in special pyramid-shaped crates.
- Male plants give the higher total yield while female plants produce larger individual spears.
- Yield varies with varieties, region, climate, and sex form.
- On an average, 25-40 q spears are produced in one hectare
- Asparagus can be stored for 2-3 weeks at 95 per cent relative humidity and at 0-2oC.
- Spears stored in wet tissue paper looked fresh and firm after 13 or 16 days of storage.