Asparagus (Asparagus officinalis) is a member of the lily family (Liliaceae) and is one of a few vegetables that are monocots (plants having only one cotyledon or seed leaf). Both male and female flowers are produced on the older asparagus varieties, but there are very few to no female flowers produced on the newer all-male hybrid varieties.
Spears are generally harvested when they are 7 or 9 inches in length and are generally green in color. A new purple spear variety has been developed by plant breeders. Excluding light when spears are emerging will produce blanched or white spears.
Asparagus is believed to be indigenous to parts of Russia, the Mediterranean region, and the British Isles. It was first cultivated by the early Romans who used the asparagus for food and medicinal purposes. It was cultivated in England at the time of Christ and brought to America by the early colonists. However, asparagus was not extensively planted by commercial growers until after 1850.
Most of the asparagus harvested in the U.S. is sold as fresh produce. In 1998, the U.S. produced 74,930 acres of asparagus with a value of $167 million. (USDA Statistical Services bases value of production on total acres harvested times average price.) Pennsylvania produced 500 acres, valued at $2.5 million.
Asparagus is available in Pennsylvania annually from late April through June. It is traditionally sold in pyramid crates packed with 1.5 to 2.5 bunches held with a rubber band. Five basic marketing alternatives are available to the asparagus grower: wholesale marketing, cooperatives, local retailers, roadside stands, and pick-your-own operations.
In wholesale marketing, producers often contract with shippers to market and ship asparagus for a predetermined price. If you do not use a contractor and ship your asparagus to a wholesale market yourself, your product will be subject to the greatest price fluctuations. Marketing cooperatives generally use a daily pooled cost and price, which spreads price fluctuations over all participating producers. Local retailers are another possible market, but you must take the time to contact produce managers and provide good-quality asparagus when stores require it. Roadside stands (either your own or another grower's) and pick-your-own operations provide opportunities to receive higher than wholesale prices for your asparagus, but you may have some additional expenses for advertising, building and maintaining a facility, and providing service to your customers. With pick-your- own operations, you save on harvest costs, but you must be willing to accept some waste. Depending on your location, processors may or may not be a marketing option. Processors are less likely to contract with small-acreage growers (those with less than 5 acres). For more information on marketing, consult Agricultural Alternatives: Fruit and Vegetable Marketing for Small-Scale and Part-Time Growers.
Asparagus should be grown on well-drained soils that have good water-infiltration rates and good moisture-holding capacity. The soil should not be compacted and the pH should be 6.2 to 7.0. Growers should avoid planting asparagus in fields where it has been grown in previous years. Asparagus is an alleopathic species—it produces and releases toxic chemicals that inhibit and suppress the growth of young asparagus transplants or crowns. In addition, asparagus is extremely susceptible to Fusarium root rot, a soil fungus which will weaken the plant. Fusarium can survive up to 7 years in infected soil and soil fumigation is not effective in reducing long-term Fusarium populations in the soil. Asparagus is extremely salt tolerant.
Planting and Fertilization
Commercially, asparagus can be started in the greenhouse 8 to 10 weeks prior to transplanting in the field or planted as 1 or 2 year old crowns. Crowns are developed root systems with a fairly defined storage organ and growth buds. Growers generally plant approximately 12,000 to 14,000 plants per acre in single rows, with 12 inches between plants in the row and 5 to 6 feet between rows. Whether planting crowns or transplants, the asparagus is planted in an 8-inch deep furrow with a W-shape configuration at the bottom of the furrow. The crown and transplant are planted in the W-shaped furrow beneath the soil surface, and the furrow is gradually filled with soil during the growing season. Asparagus usually is planted in May so that extensive foliage (fern) develops before winter.
Fertilizer recommendations should be based on annual soil test results. In absence of soil test results, the recommended N-P-K application rates are 50-100-150 pounds per acre broadcast in the spring of every year before spear emergence.
Weed control can be achieved with a good crop rotation system, herbicides, and straw mulch. Several preplant and post emergence herbicides are available for asparagus, depending on the specific weed problem and the time of year. If infestation levels are mild, early cultivation (prior to spear emergence) can help minimize weed problems.
Insects can be a major problem in asparagus production. Asparagus beetle, asparagus aphids, cutworms, and Japanese beetles all can cause crop losses. Monitoring insect populations will help you determine when you should use pesticides and how often you should spray.
Several asparagus diseases can reduce crop yields, especially fusarium root rot and rust. These diseases can be prevented by having a good crop rotation system, soil with good water and air drainage, and by using disease-resistant varieties.
Harvest and Storage
The harvesting period for asparagus is increased gradually from planting to full maturity (5 years). Harvesting asparagus when it is greater than 12 inches in length (spear diameter becomes thinner) will reduce the total marketable harvest over the life of the planting. The first year after planting, asparagus can be harvested for about 7 days, the second-year harvest period lasts for about 14 days, the third-year harvest period is about 3 weeks, the fourth-year harvest period is 30 to 36 days, and by year five (when the plants have reached full maturity) the harvest period is approximately 6 to 7 weeks. Asparagus spears can be cut with an asparagus knife or snapped off near the soil line. Spears are harvested when they reach at least 7 inches in height and have a spear diameter of at least 5/16 of an inch. When growing under seasonal temperatures, asparagus should be harvested every day since spears can increase in length as much as 2 inches per day.
Removing field heat from asparagus is critical for extending their shelf life and maintaining a good appearance. Refrigeration immediately after harvest will help guarantee high quality. Asparagus that is maintained at 32 to 36 degrees F and 90 to 95 percent relative humidity will retain good quality for approximately 7 to 14 days.
Included in this publication are two sample fresh-market asparagus budgets. Both budgets utilize custom hire for most of the field work, which could be more economical for a smaller acreage. Farmers who have their own equipment should substitute their costs for the custom hire. The first budget summarizes the costs of establishing an asparagus enterprise (there is no income during the year of establishment). The second budget summarizes the receipts, costs, and net returns of an asparagus enterprise for the first year after planting, the second year after planting, and a mature crop. These sample budgets should help ensure that all costs and receipts are included in your calculations. Costs and returns are often difficult to estimate in budget preparation because they are numerous and variable. Therefore, you should think of these budgets as approximations and make appropriate adjustments in the "Your Estimate" column to reflect your specific production and resource situation. More information on the use of crop budgets can be found in Agricultural Alternatives: Enterprise Budget Analysis.
You can make changes to the interactive PDF budget files for this publication by inputting your own prices and quantities in the green outlined cells for any item. The cells outlined in red automatically calculate your revised totals based on the changes you made to the cells outlined in green. You will need to click on and add your own estimated price and quantity information to all of the green outlined cells to complete your customized budget. When you are done, you can print the budget using the green Print Form button at the bottom of the form. You can use the red Clear Form button to clear all the information from your budget when you are finished.
You will need Adobe Acrobat Reader to use these forms. If you do not have this program installed on your computer, you can download a free version.
Sample Budget Worksheets
- Sample Asparagus Budget-Establishment
- Sample Asparagus Budget-Year Two
- Sample Asparagus Budget-Year Three
- Sample Asparagus Budget-Year Four
Initial resource requirements
Land: 1 acre
Labor: 24 hours
- Harvesting and grading: $800 per acre
- Depreciation on equipment: $300
For More Information
Cantaluppi Jr., C. J., and R. J. Precheur. Asparagus Production, Management, and Marketing (Bulletin 826). Columbus, Ohio: The Ohio State University, 1993.
Hardenburg, R. E., A. E. Watada, and C. Y. Wang. The Commercial Storage of Fruits and Nursery Stocks (USDAARS, Agricultural Handbook Number 66). Washington, D.C.: Superintendent of Documents, Government Printing Office, 1986.
Lorenz, O. A. and D. M. Maynard. Knott's Handbook for Vegetable Growers. 3rd ed. New York, N.Y.: John Wiley and Sons, Inc., 1988.
MacNab, A. A., A. E. Sherf, and J. K. Springer. Identifying Diseases of Vegetables (AGRS-21). Penn State Cooperative Extension, 1983.
Pennsylvania Commercial Vegetable Production Guide (AGRS-28). Penn State College of Agricultural Sciences, 2000.
Tetrault, R., A. A. MacNab, P. A. Ferretti, and M. D. Orzolek. Asparagus Production for Small-Scale Growers and Gardeners (U.Ed. 86-601). University Park, Pa.: The Pennsylvania State University, 1986.
Prepared by Michael D. Orzolek, professor of horticulture; George L. Greaser, senior research associate in agricultural economics; and Jayson K. Harper, associate professor of agricultural economics.
To view a PDF version of this publication, click on the PDF icon at the top right of this page.
This publication was developed by the Small-scale and Part-time Farming Project at Penn State with support from the U.S. Department of Agriculture-Extension Service.