Asparagus, also known as garden asparagus or sparrow grass is a valuable perennial flowering crop that regenerates year after year once planted. It is one of the first crops of the season to harvest every spring grown vigorously in cooler regions with longer winters.. The edible portion of asparagus is their tender spears.
Nutritional facts of Asparagus:
Asparagus is one of the most nutritionally balanced vegetable having many health benefits:
- They are low in calories, free from fats and cholesterol.
- Folic acid, which is synthetic form of folate that is vitamin-B, is found in asparagus which is the most required for human during pregnancy that helps to form neural tube.
- The amino acid asparagine, which is found in very low level in asparagus, acts as a diuretic.
- They are source of vitamin-A, vitamin-K and vitamin-C.
Vitamin-A: Helps in bone growth, vision, reproduction etc.
Vitamin-K: Plays an important role in blood clotting and keep the bones healthy.
Vitamin-C: An anti-oxidant that helps the skin, bones and connective tissues and
also is important for iron absorption.
- They also helps in weight loss,reduces the risk of the diabetes, lower the blood pressure.
- They are high insoluble fiber, which attracts water into the stool making in softer and easier to pass with less strain on bowel.
Asparagus spears are frost sensitive. Frost damages the spears as they are starting to emerge. It is grown from cool temperate regions to the subtropics but also grown in the tropics although yields are not as prolific and plants don’t last as long. Plants need temperatures between 25 to 30 degrees Celsius during the daytime and 16 to 20 degrees Celsius at night. Asparagus plants start to produce new shoots when soil temperatures rise above 10 degrees Celsius,growing best around 1000 m above sea level.
Asparagus are water prone and hate the water logged condition. So, the soil should be fertile and well drained with good air movement. Further, asparagus cannot tolerate extreme acidity so it should be grown on sandy silt loam or alluvial soil with a pH range of 6.5-7.0. Make sure that the soil is free from insects and perennial weeds such as Bermuda grass or Johnson grass.
Before planting, it is best to have the soil test of the planned site, sample taken down about 12 inches deep so that, if your soil is not perfect, you can dig in plenty of well-rotted manure or garden compost to improve the soil structure and fertility. In the same way the required soil pH can be maintained according to the soil test recommendation.
Propagation method and planting time :
Asparagus is usually propagated from one-year old crowns but can also be propagated from seeds as well. Asparagus crowns should be planted in early spring and many gardener plants about the same time when potatoes are grown.
It is one of the most common method of propagation. When the production of spears slows down over several years, it is time to cut the root into pieces. Dig up the root in late fall after the last fern has died back. Cut it into several pieces, each with plenty of healthy root attached. Replant them then or wait until spring after the last frost.
Older asparagus plants produce red berries, which contain seeds. Collect the berries, crush them and separate out the seed.
1) Before sowing, soak seeds in water for up to 24 hours.
2) Sow seed in moistened peat or peat cups indoors in spring.
3) When plants reach to the height of 12 inches, they should be taken outdoors for hardening at least for a week.
4) After the last spring frost, transplant the young plants to a temporary garden bed. Once they mature, identify the berryless male asparagus plants and transplant them to permanent planting site, removing the less productive female plants.
Planting method ( how to plant)
1) Start off by digging a trench of around 10 inch deep and 12 inch wide.
2) For good fertility of soil, fill the bottom of each trench with about 3 inch of well-rotted manure or garden compost.
3) The initially dug soil can then be piled up on the top of the manure to form a ridge along the length of the trench so that it will support the fragile roots and ensure good drainage.
4) Asparagus plant will need plenty of space in the coming year, so at the distance of 18 inches apart, lay your crowns in place carefully, spreading the roots out across the top of the mound.
5) Gently cover the roots and crowns with 3 inch of soil and water them well to settle the soil.
Irrigation is important to overcome drought stress, particularly during the first two seasons of crown planting. So, for the best production, water is essential. Mostly, an inch of water per week is sufficient but in drought condition, a deep soaking in every 10-14 days is recommended. Besides, heavy mulching will keep the soil moist.
Asparagus is not a very good competitor of weed. The crowns of asparagus have spidery roots that unite together in the ground, which create difficulties in improving soil to control perennial weeds so these troublesome perennial weeds must be controlled prior to crown planting. Weed can be controlled by various methods like mechanical control by hand hoe, cultural control by mulching and chemical controls. If weeds arise during the growing seasons gently hand pulling without disturbing asparagus’ root is required .
The amount of fertilizer to be applied depends on soil test recommendation that is tested before planting in late or early spring. Before planting, incorporate 100 g of N, P and K per 20 feet of row or as directed by soil test report. Asparagus also require early spring fertilization just before they begin to produce shoot so 1 kg of fertilizer per 20 feet of row should be scattered for full establishment of crop. And after the last harvest, apply an additional 0.5 to 1 kg per 20 feet of row. Always water the fertilizer into the soil.
1) Asparagus spears should not be harvested during first season instead the development of foliage should be allowed which will help to feed the plants and encourage for better and healthier growth next years.
2) A limited crop of about half the spears can be harvested in the second years when they reach 6 inches tall.
3) By third year, you will be able to harvest the full crop from April to the start of June.
4) To harvest, simply cut the spears at about 2 cm below ground level with the help of any sharp knife.
5) Younger, thinner spears will be tenderer so harvest according to your taste.
6) Asparagus spears are fast growing so you will need to check your crop every day. It is recommended that you stop cutting by the start of June to allow any remaining shoots to develop into foliage.
7) After harvest, fertilize your asparagus in early summer. You can top dress with a balanced organic nutrient or weed free compost.
8) Allow the ferns to grow and mature which provides the nutrients for next year’s spear production. Always leave one or two spears.
9) It is also important to keep them well watered during hot periods to prevent the roots from drying out.
10) Once the foliage begins to turn yellow, you can simply cut back the stem to ground level and mulch the rows with some well-rotted manure to protect the crowns from winter weather.
Pests and diseases
Cut worms, asparagus beetle, asparagus aphid, grass hopper etc. are the pests that attack asparagus crop. Among them, asparagus beetle is the worst pest that causes holes or pits in spears. This beetle can greatly damage asparagus in a short period so if you see beetles feeding on asparagus, remove them by hand or spray them with organic insecticide “sevin”.
Common diseases that attack asparagus are crown rot and rusts. They can be controlled with organic chemicals such as sulfur or potassium phosphite.