Dual Season Organic Asparagus Production

Final Report for FS09-233

Project Type: Farmer/Rancher
Funds awarded in 2009: $9,995.00
Projected End Date: 12/31/2011
Region: Southern
State: South Carolina
Principal Investigator:
Mary Connor
Three Sisters Farm
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Project Information


A study of the viability of dual season organic asparagus crops in the coastal region of South Carolina determined that this is a feasible operation. Although costs for organic production are high, demand for this crop is also high. The ability to manipulate fall harvesting by time and quantity is especially advantageous for specific local markets. This study showed that both spring and fall harvested organic asparagus are possible and that asparagus is a desirable crop for the coastal areas of South Carolina and Georgia.


South Carolina was once the largest producer of asparagus and asparagus was one of the largest cash crops in the state in the 1930’s. In subsequent years New Jersey, Delaware and California were able to capture the market largely due to lower transportation costs to large metropolitan areas. As northern populations migrate to the south, and transportation costs continue to increase, a window of opportunity opens to South Carolina growers to resurrect the market for asparagus. As many as 10,000 acres of asparagus were cultivated in South Carolina in the early part of the 1900’s. Presently it is estimated that less than 25 acres are cultivated for commercial production in the state of South Carolina.

With resort communities flourishing along the coastal areas of Georgia, South Carolina and North Carolina, farming communities paralleling this coastal band can take advantage of lower transportation costs and the demand from more sophisticated and affluent consumers for local and organic produce.

Southern coastal growers adjacent to urban and resort communities have not taken full advantage of the increased demand for local and organic farm products. New markets becoming available to growers must be pursued to take advantage of this opportunity to bring higher quality produce to consumers. As development pressures push further inland from coastal areas, traditional farming communities are less inclined to continue farming and more inclined to abandon farming in favor of selling of farmland to real estate development interests. With an understanding of changing markets and the innovation of new crops, this trend could be replaced by one which expands opportunities in farming.

After the award of this SARE grant (2009), economic changes have drastically affected the coastal economies of the area. Assumptions of development pressures have been altered as the economy has slowed. However, interest in healthy home prepared meals has increased demand for local organic foods. The number of farmers markets where farmers sell directly to consumers has tripled in the study area (Bluffton/Hilton Head/Beaufort ) thus making the direct retail market for farmers more accessible and has allowed farmers to increase production for this more lucrative market.

Dual season organic production of asparagus is a good choice for farmers in the coastal areas of the Southeast where mild winters present a long growing season. Results from this study indicate that one or two seasons of market may be more economically favorable by virtue of production and market constraints.

The intensive labor requirements of organic asparagus production are high, but fresh, organic asparagus commands a high price at the retail level. Due to increased fuel and energy costs in the present (and anticipated in the future), a clear competitive advantage has been created for the markets for asparagus in the areas near the farm operation.

Because asparagus is a particularly perishable crop, the ability to time the quantity of second harvest or a fall harvest is very desirable. Timing harvest will reduce refrigeration needs as well as reduce the chance for deterioration in refrigeration. Reduced refrigeration time not only limits the chance of deterioration, it also produces a superior tasting product which is appreciated my most consumers as well as sophisticated chefs who want to offer more local and organic produce to their menus.

Project Objectives:

In this study, two problems were simultaneously evaluated. First, the viability of dual season organic production of asparagus and secondly, evaluating dual season markets for organically produced asparagus.

The study’s performance targets were first to produce asparagus using organic methods and determine if this crop could be viable using organic methods. This would be evaluated by visual and laboratory tests of tissue samples to determine the health of the plants.

The second part, the marketability of asparagus in dual seasons would be tested by actual sales. Whether or not organic asparagus would be economically practical would be determined by actual sales and evaluating costs associated with production.

Because of the labor intensive requirements of asparagus production, whether conventional or organic, the production costs for these do not vary as vastly as other conventional crops. Therefore, this organic crop is ideal for competing with its conventional counterpart.

In recent years Clemson University has undertaken research to improve cultivation of conventional asparagus using trial gardens This effort has produced research data for use by growers.

This research, while invaluable, cannot be directly applied to organic production. Therefore, studies using organic methods must be field tested. Market testing using real conditions is invaluable for determining the viability of markets


Click linked name(s) to expand/collapse or show everyone's info
  • Priscilla Coleman
  • Barry Connor
  • York Glover
  • Shawn Jadrnicek
  • Beth Lee


Materials and methods:
Introduction to Methods

Asparagus crowns were purchased from two northeast (US) wholesale asparagus crown farms. These were not certified organic crowns. Because of the timing of the grant award, we could not place an order in time before the organic crowns had been sold out from the available organic vendors.

Consulting with our extension agent Shawn Jadrnicek who in turn consulted with Dr. Robert Dufault from the Clemson University Experiment Station, we determined the best variety for the area. Clemson University had just completed test plots at the Coastal Experiment Station near Charleston , South Carolina, therefore there was excellent research data on the best varieties for the coastal zone. The supplier was consulted as well for their opinion of the best varieties for the area.

Several selections were made in accordance with recommendations from both our grant contributors and the vendors themselves. Also, the selected varieties were chosen to accommodate differing production schedules for anticipated clientele.

While some organic crowns were available at the time the order was placed, they were not the varieties sought for the project or suitable for area’s climate and soil conditions Since there were no available sources for organic crowns meeting our requirements (at the time of the program start), we purchased conventional crowns. Because the crowns would be managed using organic methods over one year before any harvest would take place this was deemed to be acceptable.

Although purple varieties were not recommended by the researchers, we chose to place one forth of the area in purple asparagus because of our own experiences with colored varieties of produce which anecdotally had produced good resistance to insect pressures. Additionally, colored varieties have added market value. The varieties chosen were Jersey Supreme, Purple Passion, and Jersey Giant.

Site Selection

After the grant award, we began evaluation of empty fields for potential locations for the project noting potential problems or advantages of each field. All of our potential fields had been certified organic for two previous years.

After comparing fields it was decided to use the daffodil field in which we had begun removing bulbs for relocation two years ago. This field had the best soil structure for asparagus and the least amount of grass. It had very little Bermuda grass. It did have centipede but this type of grass is much easier to control than the Bermuda. Also, there is a hose bib nearby which could be used to expand irrigation.

Site Preparation

We began removing the remaining daffodil bulbs from the field. Two additional workers were hired to assist us with this task we were able to completely clear the field of the remaining bulbs estimated to be about 6000 bulbs.

The field was plowed with a sub-soiler. The field had been grown up with small trees, mostly gums mixed with the daffodils, but mowed down annually. These had very large root systems even though the trees were merely bushes. Roots were picked up and taken out of the field. The field was then plowed with disk harrow.

The field was next tilled with rotary tiller. A bowl became evident and this was corrected using a blade to crown the field to make drainage flow to the ends of the fields.

Planting, Culture and Maintenance

The soils test report indicated the need to add lime to correct the pH. Lime was spread the at the recommended rate (1700 pounds per acre) to the project site using a rotary fertilizer spreader (spinner). A rotary tiller was used to incorporate lime into soil.

Coastal soils are naturally high in phosphorus. The other recommendation was for potassium. This was not applied until after the crowns had been planted due to the difficulty of obtaining a source suitable for organic production. Fertrell’s SeaK was applied later in the year. Boron in the soil was adequate from the soil tests.

A cultipactor was used to lightly compact soil before making trenches to receive crowns. Trenches were made with a middle buster approximately 8 inches deep (from level ground). Fertilizer was added to trench bottoms. The fertilizer should be wetted before plants are placed. Since it rained, we were able to skip this step.

Fertilizer used was a Perdue chicken manure based product 4-2-3 applied at the recommended rate per the soils test. Tissue tests revealed adequate nitrogen in the plants. The first year plants seemed to be growing well, but pressure from deer was beginning to take a toll and the plants were not gaining strength and size to our satisfaction. In the second year of growth, major deer pressure made it impossible to consider harvest for sales. Soil samples for the second year showed adequate nitrogen but inadequate boron. Boron was applied in December of 2010. Perdue Chicken manure based fertilizer was again applied in December 2010 (900 pounds)

The area is approximately one half acre and the recommended nitrogen for establishment is 100 pounds nitrogen per acre or 50 pounds per one half acre. Recommendation for Potassium is 150 pounds per acre or 75 pounds for one half acre, 14 bags were applied to 30- 130 foot rows at initial planting. This is 700 pounds of fertilizer or 28 pounds of nitrogen, 21 pounds of Potassium, and 14 pounds of phosphorus. Subsequent applications of fertilizer will cover the deficit.

In the weeks of April, the sprouts from the crowns began to emerge and it is estimated that about 95% of the crowns produced a viable stem. These progressed adequately for the coming months and some deer did eat some of the plants, but pressure was not heavy.

Day laborers were hired to weed rows. The most common were ragweed, crotalaria (rattlebox) and dog fennel. Weeds were allowed to grow much larger than they should have which made for very difficult weeding. It took about 6 days of crews of 4 to completely weed the crop. After that, occasional day labor when workers could be found were used along with our own in-house labor for weeding.

Throughout the fall of 2009 we continued to weed. No fertilizers or amendments were applied. After hard frost and freeze, we were able to mow down still-living plants. Some had died but many remained green until a hard freeze. A flail mower was used for mowing.

During the winter of 2009 above average rainfalls hampered the ability to cultivate. We were able to cultivate once in December after mowing. In January of 2010, rains flooded field for about 2 weeks.

In February 2010 the fields were fertilized with 350 pounds Perdue 4-2-2 organic fertilizer (chicken manure base). This was applied with a fertilizer hopper directly over plant stem. By this time we had located a suitable potassium supplement and we fertilized with 500 Sea K from Fertrell which is a 0-0-10 (organic) applied with a spreader (rotary).

Following this we began a heavy mulching with composted wood chips over stem locations. Weeds again were controlled by hand weeding. The mulching was very helpful for weed control in the following summer months. Although there were weeds, there were less than the previous year and more easily removed.

Tractor cultivation removed weeds from between the rows. A Williams tool cultivator with sweeps and spiders was adequate for this. Hand weeding was required to remove weeds close to plants.

For the second year, we anticipated being able to harvest at 10% (10% in the fall and 10% in the spring) as recommended. However, intense deer pressure prevented any harvest and the plants suffered dramatically.

We decided to harvest none of the plant fearing that we would damage what little was remaining. We made plans to fence the field in the fall. We continued to pull weeds from the plants.

In late summer, we opted to mow one half of the field to determine the viability of a fall crop in the following year.

After mowing, the fall crop emerged. It took approximately 2 or 3 weeks to have stalks that were harvestable. Again, deer came and ate all the harvestable stalks before we could.

In the latter part of summer 2010 tissue samples were again taken. All elements tested were within acceptable limits except boron. While boron was present in sufficient amounts from the soil tests, it was not being assimilated properly in the plant. Boron is an essential limiting nutrient in asparagus. After consulting with Clemson University staff, they recommended application of boron. Because of the excess phosphorus in our soils, boron was not being taken up properly by the plants.

In January of 2011, we applied 900 pounds Purdue 4-2-2 fertilizer to the rows. We also applied the boron at the same time in the recommended rates.

The part of the crop which had been mowed in late summer had additional weed pressure from perennial grasses. In the spring that followed, noticeable differences in the summer mowed crop were apparent. The spring 2011 stalks in this side were smaller in diameter and less vibrant.

By the time the spring crop was ready to emerge in 2011, we had installed a high welded wire fence to protect the crop. We decided not to harvest any of this spring crop but to allow it to grow throughout the summer to repair the damage from the deer in the preceding year.

The 2011 spring crop is vibrant and lush.

Research results and discussion:

Results indicate that there is potential for fall harvested asparagus. Experience as a small market vendor leads us to the conclusion that the ability to select both time of harvest and quantity offer enormous economic benefits. Careful timing of the harvest could insure that all products are saleable, thus eliminating both waste and the need to discount for losses, thus making this a sustainable product.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

The study had several outreach components. The county extension agents were involved by visiting the site and took samples. They were able to report to their colleagues on the test plot.

Three Sisters Farm is a member of the Coastal Organic Growers Association who meet monthly to discuss and share farming issues. A report of the findings of the study were given at a monthly meeting.

Three Sisters Farm also hosted one of the 2011Georgia Organics Conference Farm Tours. A group of approximately 30 conference attendees toured the asparagus test site on Friday March 11, 2011 . We were able to show them our project and answer questions related to the study.

Project Outcomes

Project outcomes:

The study demonstrated that organic asparagus production in the coastal zone of the Southeast is possible. An additional year of data from harvest will be necessary to fully evaluate the economic viability of the harvest, but preliminary observations indicate that asparagus is a successful and profitable crop for the coastal zone of the southeast United States.


Potential Contributions

Potential contributions of the study are that farmers now know that organic production of asparagus is possible in the coastal southeast United States. Extension agents expressed concern over the problems with weed control and disease. There were no problems with disease or insect pests over the study period. Weed control at the pre-planting stage may have decreased the need for hand weeding. Farmers can now fee confident that they could plant this crop and manage it with organic methods and be successful.

A continuation of data collection in future years will contribute to the knowledge base for organic production of this crop.

Future Recommendations

Recommendations for the future asparagus plots would include these two points in particular.

First, we underestimated the pressures of weeds. We would recommend that anyone considering planting asparagus take one or two years to fully condition the plot using cover crops to suppress weeds. We would use a combination of a clover such as red crimson followed by sudan grass in the summer, then a cereal rye the following fall. Other combinations may work better for others.

Second, we underestimated the deer pressure on the crop. Literature on the subject indicated that asparagus was not a favored crop for deer, but we found the opposite to be true. The first year had some pressure, but the second year had extraordinary pressure. We regretted that we had not had the forethought to install fencing during the first season. This would have made the plants stronger and more able to shade weeds in late summer.

When we begin to harvest, we will learn more about harvesting this crop. We would recommend during the time spent preparing the site (with cover crops, clearing, etc) for a large asparagus crop, it may be wise to have a small crop to experiment with varieties and harvest techniques.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.