Evaluation of a Perennial Vegetable, Asparagus, as a New Commercial Crop for Hawaiian Farmers

Final Report for SW96-003

Project Type: Research and Education
Funds awarded in 1996: $49,595.00
Projected End Date: 12/31/1999
Matching Non-Federal Funds: $9,973.00
Region: Western
State: Hawaii
Principal Investigator:
Susan Schenck
Hawaiian Agriculture Research Center
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Project Information


[Note to online version: The report for this project includes tables that could not be included here. The regional SARE office will mail a hard copy of the entire report at your request. Just contact Western SARE at (435) 797-2257 or [email protected].]

The following report covers activities for the duration of the SARE project, Evaluation of a Perennial Vegetable, Asparagus, as a New Commercial Crop for Hawaiian Farmers. The project was installed and maintained by the cooperating farmer, Mr. Milton Agader with coordination and assistance of Hawaii Agriculture Research Center Pathologist, Dr. Susan Schenck.

Asparagus seeds for the project were planted in flats to germinate and then transplanted to the field. The field plots were covered with polyethylene mulch and drip irrigated. Fertilizer was applied through the irrigation system. The ferns were allowed to grow for one year before the first harvest took place on December 15 - 22, 1998. It was a short harvest period with a relatively small yield. The ferns were then allowed to regrow and subsequent harvests occurred at about six month intervals. Four harvests have now been completed and the yield results are attached. The two summer harvests were large, while the winter harvest was smaller. However, the higher prices in winter partially offset the lower yields. It is clear that asparagus is a sustainable crop for Hawaii and that the growing methods are compatable with farming systems of the local growers.

Since this project was limited in size, it is difficult to assess the actual production costs and eventual profitability. The cooperating farmer has increased his asparagus acreage from the original 1/2 acre to over 4 acres and is preparing to install another 40 acres. He is convinced that the crop will be profitable as soon as he can find competent workers as needed. As a result of the information disseminated to local growers, there are now a number of growers interested in planting asparagus and forming a cooperative marketing agreement. There are also at least three asparagus farms on other Hawaiian islands. It is clear that an expanding local market is available and buyers are learning that they prefer the fresh local asparagus. There are many hotels and restaurants in Honolulu and the supermarkets have also expressed an interest in the local product. The growers are now in need of marketing assistance. They are not yet able to supply large supermarket chains on a continual basis, but this is an eventual goal. For now they are hoping to develop a local market with the restaurants which are known to demand top quality.

Project Objectives:

1. Establish appropriate irrigation and fertilizer practices.

2. Determine plant density for viable commercial production in Hawaii.

3. Provide least toxic management of insect and mite pests, diseases, parasitic nematodes, and weeds.

4. Determine the cost of production, number of harvests per year, yield per acre, and profitability.

5. Disseminate the information gathered from the project to growers through field days, publications, and seminars.


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  • Dr. Susan Schenck


Materials and methods:

During the first year the asparagus planting plot layout was established and plants were started and transplanted to the field. Proposed crop maintainance procedures were followed and the crop growth and health was observed and reported. At the end of 1997, the first harvest took place and the results were made available to farmers. Following the first harvest, the asparagus was again allowed to grow to ferns and was watered and fertilized as before. The second harvest took place in August 1998, the third harvest in Jahuary 1999, and the fourth harvest in August - September, 1999. The planting will continue to be maintained by the cooperating farmer and is expected to continue yielding a marketable crop every six months for the next 10 to 15 years.

The irrigation schedule for the project was dictated by the availability of water. The project area was irrigated for 2 to 3 hours every other day. This proved to be quite sufficient for this location. During the first year of the project two different fertilizer rates were tested. The results showed that there was no difference in yield between the two, so consequently, after the first harvest the entire project area continued to receive the lower rate. Fertilizer applied was 11-37-0 and urea for a total per crop of 81 lb/acre phosphorus and 80 lb/acre nitrogen.

The asparagus seedlings were planted at a density of 1 plant per foot in lines 4 feet apart. This proved to be suitable spacing and as the ferns grew, the canopy closed in sufficiently to shade out weeds. Asparagus produces an extensive root mass that continues to spread and remains productive for years. Asparagus is a very low maintainance crop with few nematode, insect or disease problems. During the first year of growth there was one Cercospora fungus blight outbreak requiring fungicide treatment, but no problems were encountered during the rest of the project duration.

It is now evident that with sufficient irrigation and fertilization, two harvests per year are sustainable in Hawaii. The first harvest was small, the second harvest in August 1998 was larger, the third harvest, which occurred in cooler winter weather, was smaller, but still larger than the first harvest. The fourth harvest in August of 1999 had the largest yields of the four harvests. There were eight varieties in the trial and some proved to be more suitable to Hawaii conditions than others. The yield data and variety performance are presented in the attached tables.

Research results and discussion:

Objectives 1 through 3 were accomplished. The irrigation and fertilization practices and planting procedures proved to be suitable for asparagus production in Hawaii’s subtropical environment. In temperate regions, asparagus ferns die back each winter and the regrowth in the spring is the single harvest for the year. In Hawaii, we were able to sustain two harvests per year and these could be scheduled as desired to take advantage of market prices. Instead of a cold period, the irrigation is stopped for one month allowing the ferns to die back and rest. Upon renewing the irrigation and fertilization, spears again sprout and are harvested. By drying out different sections of a farm at successive intervals, continual production can be maintained.

The planting density of one plant per foot and rows at four foot intervals resulted in good production. It is probable that a number of different planting densities would be suitable because over time the asparagus roots form a spreading mass that covers a larger area than the original planting. There were virtually no insect of disease problems in our test plots, although a number of diseases of asparagus occur in Hawaii. It is likely that these diseases would be more prevalent in more humid, higher rainfall areas of the state. Nonetheless, they will be controlable with currently registered fungicides. Weeds must be controlled during the period between transplanting seedlings and closing over of the ferns, but after that there is little weed pressure for the life of the field.

Objective 4 was also accomplished. The number of harvests per year was determined to be two. The yields per acre for each of the varieties for each of the four harvests were determined and are presented in Tables 1 - 4. There were three New Jersey and five California varieties tested and the California varieties did better in Hawaii. Varieties Apollo and Atlas consistently had the highest yields in pounds per acre of all spear sizes combined. However, one of the New Jersey varieties consistently produced higher numbers of small size spears which are preferred by some comsumers. I have been in contact with the California seed producer who was interested in knowing the results of this project. He is now supplying seeds for Hawaiian growers. It may be that, in future, breeding programs could be undertaken to produce uniquely Hawaiian varieties that yield even better. Cost of production and profitability on a large commercial scale with developed local markets is hard to estimate from this small trial. However, Mr. Agader is convinced of the profitablility of asparagus. The problems remaining to be worked out are the hiring of well-trained workers and development of markets for continual production.

Objective 5 was dissemination of information. This succeeded even better than expected. We found that there was a great deal of interest in Hawaiian asparagus among potential commercial growers, home gardeners, and customers. Several media events took place. The extension agent, Mr. Steve Fukuda, mailed out information and helped to organize a field day during the second harvest. This was well-attended and generated lots of interest and questions. Photographs of this event were sent with a previous report to SARE. Several other media events also took place. Dr. Schenck was invited to speak on a Japanese language radio broadcast (with translator) about asparagus and other alternative crops in Hawaii. Both Dr. Schenck and Mr. Agader appeared in two succesive television programs of a local gardening show. These were filmed both in the asparagus field and in the laboratory and were taped on a video which can be replayed for those interested. A copy will be sent to SARE if requested. Dr. Schenck attended a conference of the Hawaii Organic Farmers Association (HOFA) and showed photos and gave information to the organic growers about asparagus. Although organic farming is still a small sector of Hawaii’s agriculture, it is growing and asparagus is a sustainable crop for organic production. In April of 1999 an Agriculture Day was held on Oahu sponsored by the University of Hawaii. Agriculture products retailers, commercial growers, restaurants and research groups all had booths. Over 2000 people attended in 1999. Hawaii Agriculture Research Center also had a booth and, among other projects, the SARE asparagus project information was shown with photographs. A handout was presented that contained information on seeds, growing methods and variety yields (see attachment). A comprehensive article appeared in the February 3 issue of the Honolulu Star Bulletin in the Today section (see attachment). Another recent article about asparagus production in Hawaii also appeared in the Aloha Airlines monthly magazine which is read by hundreds of tourists and interisland passengers. We are very gratified by the response in Hawaii to our project and the expanding acreage of this crop in the islands.

Research conclusions:

Many agricultural workers in Hawaii that previously worked for the sugarcane and pineapple companies are no longer employed with them since these large plantations have significantly reduced their acreage. Some of these workers have turned to small farming operations and are thus in need of information and assistance in developing new crops and markets for their produce. This project was undertaken to educate and inform Hawaiian farmers about asparagus which has great potential as a profitable alternative crop for Hawaii. Not only can it fill a local market that is now supplied by imported asparagus, it is a low maintainance, sustainable crop with little need of pesticides and with good soil erosion control. The extensive root mass that develops keeps soil in place and does not require plowing or replanting. Once planted, the farm remains productive for about 15 years. In Hawaii, unlike temperate regions, harvests can be scheduled at any time of year when supply is low and prices are high.

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach Outcomes

Recommendations for education and outreach:

Areas needing additional study

This project began as a small demonstration field of 1/2 acre. It succeeded very well in promoting asparagus as a new crop for Hawaii and the acreage of this crop continues to increase. Thanks to generous media coverage, Hawaiian consumers have also become interested in obtaining the fresh, locally grown spears. It also appears that hotels and restaurants, of which there are a great number in Honolulu, will be interested in a continuing supply of top quality asparagus. It is not yet clear which spear sizes will be the most in demand and what the best marketing strategy will be. Eventually, it will most likely be advantageous for the farmers to form a cooperative so that the best prices can be negotiated and consumers may be assured of a continual supply of fresh spears.

The future recommendation indicated by our research to date is that the asparagus farmers now need research and education into marketing their asparagus. The local market appears to be available, but untapped, or rather is currently being supplied from the mainland USA. It is not known how large the local market will be, which size spears will be most in demand, how prices will vary during different seasons or which market sectors will be the most profitable to supply. There is also the possibility of eventually expanding enough to export to foreign markets, most probably Japan. Much more work needs to be done in the area of marketing in order to help Hawaiian asparagus growers establish themselves in permanent, sustainable, profitable production.

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.