Asparagus Growing Instructions
Asparagus is a perennial crop that will last for many years, if properly maintained. Plant once and enjoy for 15-25 years, Rich in Vitamin B and C, calcium and iron... asparagus will provide you with the first vegetable of the season. And, fresh picked asparagus spears taste better and are more tender than store bought spears! Asparagus is very versatile, it can be used in salads, as a cooked vegetable, grilled, steamed, in stir fry, in sandwiches, canned, frozen and pickled.
Asparagus will thrive in all areas of the US except in the wet mild regions of Florida and the Gulf Coast. Anywhere the temperature freezes in USDA Zones 3-9 is ideal. Asparagus should be planted in an area where it can be left undisturbed for years. This could be a large field, a north edge of a garden, or part of an edible landscape. It is a beautiful plant with a soft texture, so it can be planted with other ornamental plants. Companion plants include marigolds, that help to repel beetles, basil, nasturtiums and parsley, Do not plant next to mint or onions.
Pick a spot with rich deep soil and good drainage. Asparagus will tolerate some shade, but are more vigorous if planted in full sun. Prepare soil by removing all perennial weeds and digging in aged manure or compost. IF the compost is not aged and totally cold, it will compost the newly planted asparagus crowns. Clay soils need to have abundant composted organic material tilled in. If the soils are acid, bone meal or lime will be beneficial. If your site is waterlogged in the winter, plant in a raised bed to improve drainage. Sandy loam soil will also benefit from bone meal and lime. Lime at rate of 4 pounds per 100 square feet and bone meal at 4 ounces per 5 feet of trench. A pH of 6.2 - 7.2 is best in both clay or sandy loam soils. Soil test can confirm your exact needs.
Don’t plant too early ... your air temperatures should be starting to warm to 40 to 70 degrees and your soil temperature should be close to 45 degrees Fahrenheit. This is usually about 6 weeks prior to you last frost date. If your ground is too cold, the chances of some of the crowns rotting is increased. Plant spacing can be as little as 6 inches to 1 1/2 feet apart. What determines the correct spacing is your soil type and available water for irrigation. In areas with less rainfall in the growing season and areas where irrigation water is limited, plant further apart in the row. Also in areas of humid summers, plant further apart to reduce fungus diseases. Rows should be 4-5 feet apart to create a walking path. If planted on a slope run rows up and down the slope to improve drainage. 2 or 3 rows spaced 1-1/2 ft. apart is ok in regions with low humidity in the summer. This is also beneficial in windy areas to help keeps tall plants from blowing over.
Dig a V shaped trench no more than 3-10" deep. Ohio State Univ. recommends tossing the crowns upright along the edge of a V shaped trench, and covering the entire trench at time of planting. Do not compact soil or the emergence of asparagus spears will be reduced. This is how most commercial growers plant asparagus. Apply about 2 pounds per 100 ft. row of 0-20-0 Super phosphate fertilizer in the bottom of the trench. The crown roots will not be burned by this fertilizer. The main thing to watch is that the crown buds are upright. The crown should be covered by 1/2 inch of soil initially and add up to 5 inches of soil as the plants grow depending on how cold your winter is. Contact your local Ag Extension agent for correct final cover depth in your area. Planting too deep will reduce yield. Water after planting if weather is dry. Fertilize with 2 to 3 lbs of 10/20/10 per 20 feet of row after fronds are 6 inches tall. Fertilizer can be chemical or organic.
Yearly Maintenance of Bed:
Keep bed weeded and clean to minimize disease and insect problems. After asparagus fronds have frozen and browned in the fall cut to ground and remove from asparagus bed. Some growers will cut the asparagus fronds earlier in the fall before the seeds have dropped to prevent the resulting seedlings from becoming a weed problem. This will reduce your spear yield only slightly next year. In more arid states some growers will not cut the asparagus fronds, but leave them to catch snow in the winter... and then cut them to the ground early in the spring before the new spears start to grow. Mulch to maintain moisture during the dry months and to suppress weed growth. Watering is determined by your plant spacing, time of year, and rainfall. If you don’t have adequate soil moisture in the spring before the spears appear - water to keep soil moist, but not waterlogged. During the season, if you have a tight plant spacing ( 6 inches to 1 foot) you will need to water more often than if your plant spacing is 1-1/2 feet. Usually once
every week the first year and every 2 -3 weeks is sufficient after the first year. Asparagus plants are deep rooted, 6- 8 feet deep roots are not uncommon. Once established, Do not water too often or roots can rot. Let the top several inches of the soil dry before watering again. If asparagus beetle becomes a problem, insecticidal soap or organic insecticides are effective. Fertilize in the spring after the spears have formed fern fronds. Several inches of aged manure or rich compost on top works well, or 2 to 3 lbs of 10/20/10 per 20 feet of row is sufficient. Each year the crowns will rise in the soil. In the Fall, if crowns are covered with several inches of soil, In USDA zones 3 to 5 add 2-4 inches or mulch for added winter protection.
Do not cut spears the first year. Be patient, the new plants need the photosynthesis energy to grow and store food in the roots for the next years spears. You can cut one or two cuttings the second year and 3 or more cutting the 3rd year. Stop cutting when the spears become smaller. Snap or cut the spears at ground level. Leave smaller spears to develop into fronds and leave growing till fall. Do not cut below ground level, or you may cut new spears that haven’t developed yet. Cut in the morning when it is cooler, then immerse the spears in ice cold water to remove heat. Then drain, place in a plastic bag and refrigerate until used.
Frequently Asked Questions
How many asparagus plants should I plant?
Each crown will produce about 1/2 pound of spears over a 3 week season when in full production. 10 plants per person in your family is about right for fresh eating. If you can, freeze or pickle... plant extra plants.
Why does fresh picked asparagus taste better than store bought asparagus?
Asparagus will lose its sugar content and declines in quality rapidly after cutting. Harvest spears at least every other day and you won’t get the tough spears you
sometimes get in the store.
I don’t have the space to have a asparagus bed?
If you have space limitations, use asparagus as a border or hedge plant on the north side of your garden or yard. Or, plant a few plants here and there where ever you have space. Just make sure the area has over a half day of direct sunlight and has good drainage.
Should I plant one year old or two year old crown roots?
University trials have shown that one year crowns do not suffer as much transplant shock as 2 year old crowns. Two year old crowns cost more and wouldn't produce
any faster than one year crowns. Size of crown however does matter.
What should I do if mold appears on the crown roots before I plant?
If you can’t plant right away, store your crown roots in a cool shaded area. If mold appears, dip into a water bath which contains 2% Clorox solution... then put on a rack to dry and return to the cool area.
What’s all the hype about sterile male varieties, are they better?
In a trial conducted by Oregon State University, Del Monte 361 out yielded Jersey Giant, Jersey Knight and UC 157. The main difference is that true male varieties will not produce seeds that sprout and produce a weed problem. Millennium is grown in a screened field so that there is no cross pollination from female plants, not all "male" varieties can say this, resulting in up to 40% female plants.
What is the most important things to do to be successful growing asparagus?
Plant in full or 1/2 day sun. Avoid competition from trees and shrubs by planting at least 4 feet away.
Don’t plant asparagus in an area that does not have good drainage.
The crown should be covered by 1/2 inch of soil initially.
Don’t over water asparagus.
Add abundant compost yearly and fertilize!
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