Winter Sprouting Broccoli as an Alternative Tunnel Crop in New England

Final Report for ONE09-101

Project Type: Partnership
Funds awarded in 2009: $9,981.00
Projected End Date: 12/31/2011
Region: Northeast
State: New Hampshire
Project Leader:
Dr. Rebecca Sideman
UNH Cooperative Extension
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Project Information

Summary:

Five farmers conducted on-farm trials of winter sprouting broccoli, and four of these successfully harvested crops in Spring 2010. A replicated experimental planting in high tunnels and a pilot experiment to evaluate survival of winter broccoli in low-cost low tunnels were completed at UNH in May 2010. Data were collected and analyzed in Spring and Summer 2010. When transplanted into high tunnels during the month of September, shoots were ready for harvest between mid-March and early May, depending on variety. In general the purple-sprouting cultivars, including the most readily available cultivar, Santee, were earlier than the slightly higher-yielding white-sprouting varieties. We found that the use of supplemental rowcover inside the unheated high tunnel greatly increased yields. Based on tests during two winters, overwintering this crop under low tunnels does not appear to be feasible.

Several outreach events were completed: scientific presentations at both Northeast Region (January 2010, to 40 research and extension professionals) and National (August 2010, to 60 research and extension professionals) meetings of the American Society for Horticultural Sciences; the grower article “Winter Sprouting Broccoli: a crop to consider?” was published in both the Massachusetts Vegetable Notes and Pennsylvania Vegetable Growers’ News; a Winter Sprouting Broccoli twilight meeting was conducted for 30 growers and two extension educators during peak harvest in April 2010; and one of our collaborating growers presented on this topic at a workshop to 80 producers and seven extension professionals in December 2010. In addition, the graduate student working on this project successfully defended his M.S. thesis and graduated in December 2010.

Introduction:

We planned to assess feasibility of commercial production of a new crop, Winter Sprouting Broccoli. This crop has the potential to enhance sustainability of New England vegetable operations by:

– Meeting the high demand for early spring fresh vegetables for local markets

– Providing an early season source of income

– Using existing high tunnels when they would otherwise be fallow

– Expanding low-input crop rotation options for high tunnel tomato producers

In our studies, we have shown winter-sprouting broccoli (Brassica oleracea var. Italica) has shown potential as a crop that can be grown over winter in high tunnels without supplemental heat. This crop is little known in North America, but is widely grown by niche vegetable producers and home gardeners in Britain. It is biennial and winter-hardy, producing a harvestable crop in March-May after August-September planting. The harvested product differs from typical broccoli grown in the U.S. in that it produces many long lateral shoots with purple, green or white florets, and is very mild flavored. Based on our trials, we believe that the crop has tremendous niche marketing potential; acceptance and feedback from consumers and chefs has been unanimously favorable.

We hypothesized that winter-sprouting broccoli would likely be most suited for diversified farms, particularly those farms that employ high tunnels for crop production. To identify and solve the barriers to producing this crop, potential growers that are typical of our region needed to be involved. Together with a team of interested farmers, we aimed to determine the best growing practices for commercial production of this crop in New England.

Project Objectives:
Our overall goals:
  • Cooperating growers guide UNH research on production of winter sprouting broccoli – MET
    Cooperating growers evaluate WSB varieties and production methods, and provide yield and market data – MET
    UNH researchers evaluate planting date, rowcover treatment and variety effects on yields of WSB – MET
    UNH researchers and cooperating growers share results with other growers, extension professionals, and the general public. – MET
Our specific milestones:

2009
April: Assess 2008-9 cooperating grower experiences.
May-June: Meet with current and new grower-cooperators to refine research objectives for 2009-2010.
July: Order seeds and supplies for season. Conclude experimental design.
September -October: Distribute transplants to cooperators, transplant seedlings.
November-December: Apply row cover.
2010
February: Check-in with grower-collaborators.
March-May: Harvest, take data.
April: Hold Winter Broccoli Twilight Meeting and Inservice for extension educators (flier attached).
May-June: Interpret and analyze results from 2009-2010. Update and publish Winter Broccoli Fact Sheet (attached). Prepare and submit scientific publication. (see below)
July: Poster and/or oral presentation at national conference of the ASHS.

December: Present work at grower meeting(s) focused on winger growing.
2011
February: Brassica School (see below), grower-cooperators present results.

We have met all objectives and milestones to date, with two exceptions. The two scientific publications have not yet been accepted for publication. The Winter Broccoli Fact Sheet described above has been written and provided in hard copy format to 50+ growers (attached). This is also posted on UNH Cooperative Extension’s website; available at http://extension.unh.edu/Agric/FactSheetsandResearchReports.htm. We have revised our final objective, which was to conduct a “brassica school”. Based on conversations with a subset of grower cooperators, we decided to have grower-cooperators and researchers present results in the context of other grower meetings focused more generally, rather than specifically on brassica growing.

This collaborative project resulted in good information about how to grow winter sprouting broccoli, so that growers can evaluate whether it will work for them. A brief summary of our results in terms of production information follows.

MARKETING: As a new crop, customers will require education about the crop and how to prepare it. The entire shoot (4-6” long, with leaves) is tender and sweet, and can be used in any way that broccoli or asparagus is used. It may be helpful to refer to it as ‘asparagus broccoli’ or another creative name for marketing purposes. In our experience, trial consumers and chefs have been ecstatic about the crop once it is introduced to them and they then seek it out. Restaurants or specialty markets may be the best market for the crop since the harvest season is before most farm stands and markets open for the season.

FERTILITY: Compost and aged manure was added at a rate corresponding to approximately 50 lbs N/acre in late summer, prior to planting. Spring sidedressing may be beneficial for later varieties.

PLANTING DATE: Based on our results, seeding from late Aug-early Sept and transplanting in late Sept-early Oct appears best in terms of plant survival and yield. Plants that are either too small or too large when winter arrives and temperature plummet are less likely to survive.

SPACING: We used raised beds with 3’ between row-centers. Plants were planted in staggered double rows, with 9” between each plant in a row. This corresponded to 2.25 square feet per plant. More trials are needed to determine the optimum spacing.

WINTER MANAGEMENT: Inside the tunnels, plants were covered with an additional layer of 1.25 oz spunbonded polyester rowcover during the coldest part of the winter (late Nov-early Mar). After establishment, the plants were not watered, fertilized, or otherwise managed during the winter. Winter temperatures were below 0F for several days in each of the four winters the crop was grown; in 2009 the crop survived a low temperature of -18F.

HARVEST PERIOD: In early March, it is important to remove rowcovers from covered plants to prevent over-heating and to let light in as the plants start to grow. The earliest varieties can be harvested in early March and the latest varieties will go until late April-early May, depending upon the spring weather patterns. For most varieties, harvests last for 1-3 weeks.

POTENTIAL YIELDS: At the plant spacing we used (2.25 sq.ft. per plant), a 30×60 tunnel could house 800 plants, yielding over 200 pounds. Higher yields may be possible with optimum spacing. If markets permit, leaves can also be harvested in very early spring for braising greens.

PESTS: Because the crop is grown outside the main production season, common Brassica pests (cabbage loopers, imported cabbageworm, etc.) are not present during harvest. In 2007, our plants became infested with aphids during harvest (March-April). Despite heavy infestation, aphids remained on lower leaves and did not affect the sprouts. We managed the aphids by removing the heavily infested outer leaves and introducing ladybugs (Hippodamina convergens) to reduce aphid populations.

Cooperators

Click linked name(s) to expand
  • Clifton Martin

Research

Materials and methods:

Our approach involved both on-farm and research station components.
At the NH Agricultural Experiment Station at UNH, we set up replicated experiments over two years to determine 1) which varieties are best adapted to NH, with respect to total yields, maturity dates, disease resistance, and overall performance, 2) the effects of using additional rowcover within a tunnel, and 3) the effects of using three different planting dates (mid-Aug, early Sept, mid-Sept). We collected data on yield (spear weight), duration of harvest, and harvest maturity date. We also monitored temperature throughout the fall, winter and spring months. Statistical analyses were conducted to compare the different treatments such as cultivar, row cover application, and planting date on overall performance and productivity.

For the on-farm component of the research, seeds and transplants were distributed to several growers as a pilot test evaluation of successful growing practices. Specifically, growers helped us identify additional factors that may limit adoption of this crop and guided our research station trials with their input. Our grower cooperators were asked to provide feedback after the current winter on cultural practices, questions, and economic profitability, and how to incorporate this crop into successful farming operations of varying sizes. This was done in interview format, with farm visits before planting and just before, during or after harvest.

Our outreach occurred in conjunction with the project itself. We engaged our target audience through a few different strategies. Results were published in grower newsletters (NH Vegetable and Berry Newsletter, the Vegetable and Berry Gazette in Pennsylvania, and in the Massachusetts Veg Notes), reaching several hundred growers. Results were presented in formal grower workshop settings, often (but not always) as a component of a broader talk on research updates. This also reached several hundred growers, through a combination of workshops in VT, MA and NH. Two of our successful grower-cooperators spoke about their results with the project at workshops, reaching 85 other growers. Lastly, we held a farm tour/twilight meeting specifically focused on winter sprouting broccoli at harvest time, so that approximately 30 growers could directly see the crop and interact with other grower-cooperators. In general, engagement with target audience worked well, and we continue to field questions on this crop as growers begin to experiment with it.

Research results and discussion:

The results from the University-based experiments proceeded as expected, and yielded valid and useful results.

While the results from on-farm trials were in all cases informative, they did not all yield the data that we were hoping to obtain. We had hoped to learn yield and price information from each grower, and only one grower actually sold the crop and was able to provide us with this data. Two of the growers gave the crop away to preferred customers, and a third grower included the crop in weekly CSA baskets as an “extra”. The final grower was not able to harvest the crop. This grower experimented with growing in low tunnels rather than high tunnels, and the low tunnel covers blew off in a severe windstorm in December, so the crop was unprotected for the majority of the winter and was killed. During the winter of 2010-2011, the grower that had good success with the winter sprouting broccoli established an extensive planting for spring harvest, but an unexpected mid-winter relocation to a different farm site prevented harvest of the crop. This grower intends to continue growing the crop in future years.

Despite great interest on behalf of cooperating growers, unpredictable circumstances prevented several of them from fully participating in the project, and we needed to replace some of the initial cooperators with other, very interested, participants. One lesson we learned is to cover our bases with many cooperators and to maintain good communication so that we can revise plans as situations change. Our results with the on-farm portion of the research confirmed our original hypothesis, that winter sprouting broccoli is appropriate for only a subset farms. While the crop had excellent market acceptance and appeal, the maximum yields we were able to obtain did not compete well with more prolific (and shorter-term) winter-harvested crops such as spinach, arugula, etc. This suggests that the broccoli is best suited to farmers that grow primarily during summer months and that are otherwise leaving high tunnels fallow during the winter months. Our experiences suggest that these may not be the growers most interested in adopting a crop with a novel planting schedule that requires marketing in March and April. While this was not the result we were hoping to achieve, it has been an important result, as we are able to communicate this to growers interested in this crop as they expand into winter growing.

Research conclusions:

Our verification process with the farmer participants in the project was primarily with individual farm visits and farmer-debriefings. We set up one farmer-cooperator planning meeting, but it had extremely limited attendance, in large part because of the geographic distance between farmer-cooperators and lack of time to travel, despite the availability of travel funds for growers. Each farmer was visited twice per year; once at transplanting time and once during or post-harvest (for the debriefing interview). For our target audience, our verification plan primarily involved surveys at workshops in which the project was discussed, as well as one-on-one discussions with interested farmers.

Based on preliminary results, nine cooperating growers have learned about and planted trial crops of winter sprouting broccoli. Of these, two found that it fit their growing and marketing situation well. We estimate that ten or more growers have recently evaluated the crop on a small scale as a direct result of our outreach efforts. Our work has also been of interest to home gardeners interested in season extension, but it is quite difficult to measure the impact of home scale production. Also, as a result of our outreach and requests from growers, two regional seed companies now sell seeds of this crop. The academic aspects of this work have resulted in one M.S. thesis (C. Martin, 12/10), as well as peer-reviewed abstracts and presentations at national and regional conferences. We anticipate that the work will result in two peer-reviewed manuscripts as well.

Aside from our grower-cooperators, we have been contacted by at least six growers that are interested in WSB and our results, and we know that these growers are also experimenting with the crop, in parallel with the partnership proposal. While the potential contributions are significant (increased variety of local vegetables in March-April), these contributions have not yet been realized as growers have not yet adopted this crop. Economic considerations and logistical challenges involved with scheduling crops opposite the typical production season may ultimately limit adoption by all but a few growers.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

Our research results have been disseminated to local, state, regional and national audiences through a variety of approaches. The primary target audience for our work is commercial vegetable and fruit producers in NH and neighboring states. This group has been reached through many presentations at meetings including those of the New England and NH Vegetable and Berry Growers Associations, the Northeast Organic Farming Association (NOFA) chapters in MA, NH and VT, and the Maine Organic Farming and Gardening Association (MOFGA). We also have published our research results in the New Hampshire Vegetable and Fruit Newsletter, which reaches approximately 250 growers and educators. National impact has come through publication of research results as abstracts of presentations and peer-reviewed publications in the journals and conferences of the American Society of Horticultural Science. Lastly, local citizens have been reached primarily through efforts with the NH Master Gardener program, but also through presentations to garden clubs and through Cooperative Extension publications and workshops.

Our research results have been disseminated to local, state, regional and national audiences through a variety of approaches. The primary target audience for our work is commercial vegetable and fruit producers in NH and neighboring states. This group has been reached through many presentations at meetings including those of the New England and NH Vegetable and Berry Growers Associations, the Northeast Organic Farming Association (NOFA) chapters in MA, NH and VT, and the Maine Organic Farming and Gardening Association (MOFGA). We also have published our research results in the New Hampshire Vegetable and Fruit Newsletter, which reaches approximately 250 growers and educators. National impact has come through publication of research results as abstracts of presentations and peer-reviewed publications in the journals and conferences of the American Society of Horticultural Science. Lastly, local citizens have been reached primarily through efforts with the NH Master Gardener program, but also through presentations to garden clubs and through Cooperative Extension publications and workshops.

For this project, our outreach occurred in conjunction with the project itself. We engaged our target audience through a few different strategies. Results were published in grower newsletters reaching several hundred growers. Results were presented in formal grower workshop settings, as well as several times as a component of a broader topic. This also reached several hundred growers, through a combination of workshops in VT, MA and NH. Two of our successful grower-cooperators spoke about their results with the project at workshops, reaching 85 other growers. Lastly, we held a farm tour/twilight meeting specifically focused on winter sprouting broccoli at harvest time, so that approximately 30 growers could directly see the crop and interact with other grower-cooperators.

Presentations
  1. Winter sprouting broccoli: a new crop for early Spring, New England Vegetable and Fruit Conference, December 2009, Manchester NH (115 growers)
    Production of Winter Sprouting Broccoli in New England, Northeast Regional Meeting of American Society for Horticultural Science, January 2010. Cambridge MA. (30 researchers, extension professionals, and graduate students)
    Evaluation of Eleven Cultivars of Winter Sprouting Broccoli (Brassica oleracea L.) for Potential as an Overwintering Crop in High Tunnels in New England. Annual Meeting of American Society for Horticultural Science, August 2010. Palm Desert, CA. (75 researchers)
    Winter Sprouting Broccoli Twilight Meeting, April 2010, UNH research results with growing winter sprouting broccoli, Durham NH (35 growers)
    Vegetable Research and Pest Update 2010, North Country Vegetable and Fruit Conference, October 2010, Whitefield NH. (90 growers)
    Grower Panel: Crop options for tunnel production in NH, High Tunnel Production Meeting, December 2010, Plymouth NH (85 growers)
    Winter Growing Farmer to Farmer Meeting & Tour, December 2010 Wells, Maine. (50 growers)
    Winter sprouting broccoli: a possible new crop?
    Season Extension Conference in December 2008 in Sturbridge MA
    NOFA-Vermont Winter Conference in February 2009 in Randolph VT
    Tour of SARE-sponsored Horticultural Research at the NHAES
    SARE Administrative Council Summer Tour, July 2009, Durham NH
    Tour of Horticultural Research at the NHAES
    NH Farm Bureau Board in August 2009 in Durham NH (11 NHFB members)
    USDA Foreign Agricultural Service Attache Tour of New Hampshire in September 2009 (22 foreign scientists and agricultural policymakers)
    New Hampshire Master Gardeners’ Fall Tour in September 2009 in Durham NH (43 gardeners)
    New Hampshire Master Gardeners, April 2010, (40 master gardeners)
    New Hampshire Master Gardeners, September 2010 (45 master gardeners)

Publications
  1. Growing winter sprouting broccoli in unheated high tunnels in New Hampshire. Martin CA. M.S. Thesis, University of New Hampshire. December 2010.
    Winter sprouting broccoli: a new crop for early Spring. Sideman RG. Proceedings of the New England Vegetable and Berry Conference, December 2009, Manchester NH
    Research Report: UNH Vegetable Research Update. New Hampshire Vegetable and Fruit Newsletter Vol 5:1, March 2009
    Winter Sprouting Broccoli: A crop to consider?
    NH Vegetable, Berry and Tree Fruit Newsletter, July 2008 http://extension.unh.edu/Agric/Docs/July2008.pdf
    Reprinted in UMass Veg Notes July 24, 2008 http://extension.umass.edu/vegetable/sites/vegetable/files/pdf/July%2024%202008%20vegetable%20notes%20newsletter.pdf
    Winter Sprouting Broccoli – A New Crop for High Tunnels? Online UNH Extension Research Report/Fact Sheet. http://extension.unh.edu/Agric/FactSheetsandResearchReports.htm

Project Outcomes

Project outcomes:

See above for more information. We estimate based on our results that a gross income of $1000 or more during the winter months could be produced in a typical high tunnel of 1500-1800 square feet with relatively little labor compared with other winter-grown crops. We currently estimate the total dollar impact of our work to growers and gardeners to be in the range of $5000, but we are still in the very early phases of adoption of this crop. Through our increased knowledge of this crop and its’ needs, we have been able to prevent growers from attempting to grow the crop without adequate infrastructure, saving money and permitting them to invest resources elsewhere.

Farmer Adoption

One outcome not mentioned above is that, as a result of presenting this work, farmers made suggestions that impacted our research project beyond the scope of this project. Specifically, some farmers suggested that the costs of high tunnel infrastructure was too high to warrant using the space for anything but very high yielding crops, and they encouraged us to look into feasibility of growing sprouting broccoli in unheated, low cost, low tunnels. This led us to initiate, in cooperation with other growers and researchers, a completely new line of research in the area of low tunnels. Our preliminary work in this area suggests that this is not feasible in northern New England for this crop, as the crop requires winter protection beyond that afforded by low tunnels.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Winter sprouting broccoli could almost certainly produce higher yields than we were able to produce in University-based trials by modifying growing practices, spacing, and potentially by managing the supplemental rowcover differently. This was shown by one of our grower-cooperators in year 1, who grew the crop with a small amount of supplemental heat. Additional research in the areas of rowcover management, economics, and, in warmer areas, the feasibility of growing the crop in low tunnels could all be beneficial.

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.