Enhance Strawberry Production in North Central Region through Tunnel-based Systems

Progress report for LNC21-454

Project Type: Research and Education
Funds awarded in 2021: $250,000.00
Projected End Date: 11/01/2024
Grant Recipient: Purdue University
Region: North Central
State: Indiana
Project Coordinator:
Wenjing Guan
Purdue University
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Project Information


Strawberry is a highly popular fruit in local food markets. Yet, the number of strawberry farms and total production acreage is decreasing in much of the North Central Region (NCR). The high production risks related to recent extreme weather conditions across the region has made traditional matted-row strawberry production exceptionally challenging. As a result, farmers are looking for less risky and economically feasible alternative production systems. Therefore, we will conduct research to optimize three tunnel-based strawberry production systems, i.e., the soil-based high tunnel system, table-top high tunnel system, and open-field low tunnel system. Each system will have a unique research focus; we will evaluate planting date, winter environmental management, cultivar selection, supplemental pollination, plant spacing, etc. In addition, we will develop an integrated pest management (IPM) plan targeting two-spotted spider mites and aphids, previously identified as the most destructive insect pests in high tunnel systems, and an emerging strawberry disease that may be misdiagnosed and poorly understood. Sustainable strategies including host plant resistance, natural enemies and organic biopesticides will be the focus of our IPM plan development. The project team includes extension specialists from Indiana and Ohio, and a farmer who has extensive experience in growing strawberries. In addition, collaborating farmers in Indiana and Ohio will conduct on-farm trials investigating production systems and generating economic data in on-farm situations. Based on the production and economic data generated, detailed budgets will be developed for each of the production systems. A comprehensive and interactive production guide will be produced that will provide readily available information for farmers who are interested in tunnel-based strawberry production. In addition, this project will lead to field days, workshops, growers’ conference presentations, and multiple newsletter articles. Results of research trials will be published in three to four peer-reviewed journal articles that are expected to enhance general knowledge of strawberry production and pest management. We anticipate that this project will encourage NCR farmers to adopt economically feasible and environmentally friendly strawberry production practices, which will increase farm income, reduce pesticide usage, and increase overall viability of small and diversified farms in the NCR. Further, an increased supply of strawberries in local markets will provide consumers with a popular, healthy and fresh fruit.

Project Objectives:


  1. Optimize strawberry production practices in the NCR using tunnel-based production systems.
  2. Develop sustainable integrated pest management plans for a diversity of production systems.
  3. Establish scale-appropriate budgets for the strawberry production systems.
  4. Produce and distribute a comprehensive production guide for growing strawberries in the NCR using tunnel-based systems.


Learning – improved knowledge of NCR farmers regarding strawberry production, specifically alternative production systems, strawberry physiology, and pest management.

Action – implementation of economically feasible and environmentally friendly strawberry production systems tailored to farmers’ unique situations.

System – increased farm income and enhanced diversity in local food systems.


Locally produced strawberries have outstanding market potential. For example, in North Carolina, more than 20.3 million pounds of strawberries are produced and sold exclusively at fresh markets within the state annually, creating $29.4 million in farm income (NC Strawberry Association 2016). Yet, the number of strawberry farms and total production acreage is decreasing in much of the NCR. In Indiana alone, the number of strawberry farms decreased from 233 to 199 between 2007 and 2017 and production acreage decreased from 415 to 254 (USDA 2012; USDA 2018). The high production risk related to recent extreme weather conditions across the region (e.g., late frost, excessive precipitation, and drought) has made traditional matted-row strawberry production exceptionally challenging. As a result, strawberry production in the NCR cannot compete with California and Florida production, resulting in a dramatic production decrease.

Nevertheless, regional farmers markets continue to expand. The on-going pandemic further increases demand for local foods. In addition, strawberry production in California has recently begun to decline (Guthman 2019), creating a potential opportunity for locally produced strawberries in direct-to-consumer markets in the NCR (Samtani et al., 2019). To take advantage of this opportunity, farmers are searching for less risky alternative strawberry production systems. In a survey conducted at the Southwest Purdue Agricultural Center (SWPAC) following a field day demonstration of high tunnel strawberry production in 2018, 68% of participant farmers indicated interest in exploring strawberry production using this alternative system.

In the traditional matted-row system, bare root strawberry plants of June-bearing varieties that require photoperiods of less than 14 hours to initiate flowers are set in the spring and runners develop throughout the summer to fill in the beds. Fruit is first harvested in the second year and the planting is renovated annually. Plantings are usually maintained for two to three seasons. However, as described above, the high production risks related to extreme weather conditions in the NCR makes this production system exceptionally challenging and has led to declines.

In the southern United States, matted-row production was replaced by an annual plasticulture system beginning in the 1980s (Fernandez et al. 2001). Under this system, June-bearing strawberry plugs (rooted runner tips) are transplanted in plastic covered beds in late summer or fall. Fruits are harvested in spring the following year, and after the fruiting season, plants are removed. The annual plasticulture system largely reduces the burden of weed control and facilitates harvest a few months after planting. Farmers in the NCR have expressed strong interest in using this system. Among SARE supported farmer-initiated research, winter protection materials (FNC12-895) and cultivar evaluations (FNE18-913) have been explored. However, the low yield experienced has been a barrier to wide adoption of the annual plasticulture systems in the NCR. An adjustment to this system to increase yield is to plant bare-root June-bearing plants in summer on white plastic (Roegge, 2018), but labor requirements for planting bare-root plants, and pruning runners in summer and fall have prevented large-scale adoption.

In addition to the shift in production systems from perennial matted-row to annual plasticulture, commercial cultivars have undergone tremendous changes in the past few decades. More than 100 cultivars including day-neutral cultivars that are insensitive to day length for flower initiation have been introduced to the market (Faedi et al., 2002). The continuous flower pattern of day-neutral cultivars make year-round strawberry production possible in greenhouse and hydroponic systems. However, the high costs of establishing high-tech greenhouses is prohibitive for most small-scale and beginning farmers.

High tunnels are low-cost, unheated, plastic-covered structures that provide an intermediate level of environmental protection and control. This structure protects plants from strong winds and rainfall, and provides additional heat units and moderate frost protection. Thus, growing strawberry in tunnel systems reduces production risk associated with extreme weather conditions, and creates opportunities for extended season harvest. A national USDA initiative administered through the NRCS EQIP program has facilitated a dramatic increase in high tunnel construction with 414 tunnels funded between 2012 and 2020 in Indiana alone. This does not include those that are constructed without the assistance of NRCS. As more high tunnels are built in the NCR, there is an increasing need to diversify crop production and increase sustainability of the system both economically and productively. Strawberry has the potential to be incorporated as a rotational crop in high tunnels. Strawberry’s main production seasons (fall, winter, and spring), in general, do not overlap with traditional high tunnel crops including tomato, cucumber, pepper, etc. These high-value crops can be grown in the structure following strawberry, or the tunnel can rest during the summer, facilitating cover cropping or implementation of soil disinfection strategies, which are likely be more effective and efficient in enhancing soil fertility and reducing pest pressure in the summer. Growing strawberry in table-top systems could also fit well into high tunnels. High tunnels protect fruit from rainfall and strong wind, increasing fruit quality and reducing disease pressure. The elevated system also makes harvest and plant maintenance easier. Although strawberry is one of the most popular crops grown in high tunnels in Asian countries, the value of incorporating strawberry into current high tunnel production systems in the U.S. is far from being fully explored.

Our preliminary study on soil-based high tunnel strawberry production found low-chill cultivars such as Radiance had a high yield potential and long harvest duration. Harvest up to eight weeks with yields up to 2.5 lbs/plant may be achieved, which converts to more than 2,400 lbs in a 30’ by 96’ tunnel. We hypothesize the high yield was achieved by maximized crop growth in fall and winter. Inspired by this pilot study, Adrienne Held from Holly Berry Farm started high tunnel strawberry production in Santa Claus, IN (See Support Letter). A problem both Adrienne and our team have noted is that early-flowering cultivars may bloom in winter. Flowers initiated in winter are easily killed by frosts and may potentially reduce yield in spring. In order to maximize yield potential using high tunnel systems for strawberry production, we believe it is essential to conduct additional studies to better understand plant physiology and its relationship with high tunnel environmental management. Our proposed project’s optimization of this system will directly benefit farmers like Adrienne and others who wish to expand to growing strawberries in-soil in a high tunnel.

Supported by an NCR-SARE farmer/rancher grant (FNC18-1111), one of our team members, Richard Barnes from Tanglewood Berry Farm in Fort Wayne, IN, initiated a project to evaluate elevated systems for growing day-neutral strawberries in high tunnel and open field systems. The elevated system increased worker welfare as they do not need to bend for harvesting and crop maintenance; growing day-neutral cultivars extended harvest in spring and fall. This project achieved great success and was highlighted in the NCR-SARE newsletter. To further explore the potential of using this system to grow strawberries, and introduce it to more farmers in the NCR, we invited Richard to join our team. We will work together to evaluate the effects of using different varieties, plant spacing, and planting materials in this system to further increase yield and reduce costs. The joined research and outreach efforts of farmers and researchers are expected to achieve a profound impact and benefit more farmers in the NCR.

Lastly, we explored using low tunnels for open-field annual plasticulture strawberry production. The low tunnels are supported by wire hoops and covered with perforated plastic that can be easily adopted by growers who do not have high tunnels. Our pilot study found that use low tunnels for fall planted strawberry plugs may overcome the challenge of the short fall growing window that is experienced throughout most of the NCR region. Although promising results were achieved, additional studies under varied environmental conditions are vital to understand if this system would cause any negative impacts on strawberry growth or winter survival. Additionally, economic analyses are critically needed to evaluate the economic feasibility of using a low tunnel system in annual plasticulture strawberry production.

In our initial work, we identified two-spotted spider mites (TSSM) and aphids as the predominant insect pests in high tunnel strawberry production. The spider mites infest plants in the late fall and overwinter in the high tunnels while the aphids can be found at the same time or later in the winter and their populations increase rapidly as the seasons progress. Both pests can significantly reduce yield and shorten harvest window. We noticed varietal difference in infestation rates, and that use of floating row covers inside high tunnels may impact pest development. High tunnels create unique pest situations and therefore require management strategies tailored to these production systems (Ingwell et al. 2017). Identifying the critical time of infestation, understanding pest population growth throughout the winter months, and identifying the most cost-effective management strategies (natural enemy augmentation or biopesticide application rates and timing) will help maximize crop potential.

There are a variety of commercially available natural enemies that prey upon TSSM and aphids, the most abundant and damaging pests encountered in our previous work. Augmentation biocontrol is effective in greenhouse systems but does not easily translate to high tunnels (Ingwell et al. 2018). In off-season strawberry tunnel production, when much of the structure is closed and additional floating row covers are in place, dispersal of natural enemies will be limited, thus increasing the efficacy of this strategy. The proposed study, detailed below, will help us better understand the microclimate in these protected culture systems and identify the most efficacious products, depending on the system, pest identity, and phase of crop development. 

In our preliminary work in open-field low-tunnel strawberry production, we isolated Pestalotiopsis spp. from diseased strawberries. The strawberry disease caused by Pestalotiopsis (Neopestalotiopsis) spp. was recently reported in many strawberry production regions including, but not limited to, Florida, Brazil, and Mexico (Baggio et al., 2019) and caused yield loss up to 50%. This disease can be easily misdiagnosed as the symptoms (petiole necrosis, leaf spot, and blight symptoms) are similar to other strawberry foliar diseases. Research to understand the impacts of this new disease on strawberry production in the NCR, creating tools to help farmers correctly identify the emerging disease, and developing management practices are all critically needed to assist strawberry production in the NCR.


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Soil-based high tunnel system: Our working hypothesis is that manipulation of planting date, and microenvironment management practices that enable maximized crown development and prevent massive flower initiation in winter, strawberry yield will be increased in the soil-based high tunnel production system. In addition, introducing commercial bumble bees may further increase yield.

Table-top high tunnel system: Our working hypothesis is that bare-root and plugs can be used for spring and late summer planting. Yield improvement can be achieved through variety selection and plant spacing adjustment

Soil-based low tunnel system: Our working hypothesis is that incorporating low tunnels in the fall in an annual plasticulture system will enhance strawberry crown development and increase yield in the following spring without negatively impacting plant growth and winter cold tolerance.

Materials and methods:

Objective 1. Optimize strawberry production practices for increased yield, quality, and extended harvest by using tunnel-based production systems in the NCR.

Three tunnel-based systems for growing strawberries will be closely studied, the soil-based high tunnel system, table-top high tunnel system, and open field soil-based low tunnel system.

Research hypotheses and experimental plans for each of the production systems are described below.

Soil-based high tunnel system: Our working hypothesis is that manipulation of planting date, and microenvironment management practices that enable maximized crown development and prevent massive flower initiation in winter, strawberry yield will be increased in the soil-based high tunnel production system. In addition, introducing commercial bumble bees may further increase yield.

Approach: We will use two or three strawberry cultivars that have the highest yield potential based on our previous studies. Three planting dates from mid-August to mid-October will be examined. In the winter, plants will be covered or not covered with floating row covers inside the high tunnels. Strawberry plugs will be used as planting materials for the study. They will be planted on black plastic mulch covered beds inside high tunnels. Two rows of plants will be stagger planted with one foot between and within each row. White fabric will be placed on top of black weed barriers between the rows. We previously found this practice effective in controlling weeds and preventing heat damage as it allows ripening of strawberry fruit sitting on white fabric (Figure 1). In the spring, row covers will be used on all plants to protect flowers from frost damage.

Figure 1. Strawberry are grown in soil in a high tunnel.

Each month following planting, two plants in each experimental plot will be destructively sampled. Number of crowns, crown size, and biomass distribution in fruit, leaves, crowns, and roots will be examined by measuring dry weight of plant tissues. Fruit will be harvested when they are ripe. Fruit number and weight will be recorded. We expect the main harvest season will last from the end of March to the end of May. A portion of fruit will be sampled for quality evaluation in March, April, and May. Fruit sugar content, firmness, pH, size and shape will be evaluated. A split-split-plot design will be used for the study. Winter row cover will be the whole plot; variety and planting dates will be the sub-plots. Environmental parameters including temperature, light intensity, and relative humidity will be monitored throughout the season. The research trials will be conducted in 30’ by 96’ high tunnels at Southwest Purdue Agricultural Center (SWPAC) and The Ohio State University Piketon Research & Extension Center (PREC) in Years 1 and 2.

At Purdue Meigs Horticulture Farm in Years 1 and 2, strawberries will be planted in soil in six 20’ by 48’ high tunnels. At the initiation of flowering for marketable fruit, anticipated to occur in early March, half of the high tunnels will introduce commercial bumblebees and half will not. At this time, when the sidewalls remain closed to retain heat, we hypothesize that pollination may be a factor limiting yield. By introducing commercial bumble bees, pollination of these early flowers are predicted to increase yield. Marketable and culled yield, especially the misshapen fruit that are likely caused by lack of pollination will be recorded in each system. The economic feasibility of supplemental pollination will be evaluated by comparing hive costs to potential yield gains.

Table-top high tunnel system: Our working hypothesis is that bare-root and plugs can be used for spring and late summer planting. Yield improvement can be achieved through variety selection and plant spacing adjustment.

Approach: This study will build upon research results generated by the initial NCR-SARE supported project (FNC18-1111). Strawberries will be grown in pots in an elevated system. Each plot will include a water line. In addition to the use of bare-root plants for spring planting, we will also evaluate plug plants for late summer planting. Both day-neutral and June-bearing cultivars will be included in late summer planting. Plugs will be planted with spacing at 10’’, 12’’, and 14’’. For the spring planting, multiple day-neutral cultivars will be evaluated with spacing ranging from 8’’ to 12’’. A randomized complete block design will be used for each planting. Yields of marketable and cull fruit will be recorded. Three and five fruit per experimental plot at each harvest month will be selected for quality evaluation as described above. These trials will be conducted at SWPAC, PERC, and Tanglewood Berry Farm in Years 1 and 2.

Soil-based low tunnel system: Our working hypothesis is that incorporating low tunnels in the fall in an annual plasticulture system will enhance strawberry crown development and increase yield in the following spring without negatively impacting plant growth and winter cold tolerance.

Approach: Eight to ten cultivars will be evaluated. At the end of August, strawberry plugs will be planted on raised beds covered with black plastic mulch. Low tunnels will be installed in early October. Wire hoops will be placed 4’ to 5’ apart and a perforated clear plastic will be placed on top of the wire hoops with two sides buried in the soil. Low tunnels will be in place for 4 weeks, 8 weeks, or the entire winter. Strawberry plantings without low tunnels will be the control treatment. At the end of the allotted period, the plastic will be removed. When minimal temperatures drop below 25 °F, all treatments will be covered with 2.0 oz/ft2 floating row covers for winter protection. In the spring, two plants per experimental plot will be destructively sampled to evaluate crown number, crown size, and potential cold damage to the crown. Strawberries will be harvested in May and June. Yield by number and weight will be recorded. Five to ten fruit per experimental plot will be sampled for quality evaluation as described above. This research trial will be conducted at the SWPAC and PREC in Years 1 and 2. A demonstration trial will be conducted at the Tanglewood Berry Farm in Year 2.

Objective 2. Develop sustainable integrated pest management plans for a diversity of strawberry production systems.

Insect pest management focusing on two-spotted spider mites and aphids. Our working hypothesis is that the microclimate created by tunnel systems will facilitate the establishment of natural enemies and biopesticide pathogens that will provide pest suppression.

Approach: The seasonal abundance of pests will be monitored across all production systems described in Objective 1. This will entail bi-weekly surveys of the crop. We are specifically interested in examining how the use of floating row covers inside the tunnels impact pest development and how susceptibility varies across cultivars, therefore cultural practices and varietal selection will be compared.

To develop management recommendations, we will evaluate the efficacy of augmentation biocontrol (releasing natural enemies from commercial suppliers) in conjunction with the application of biopesticides as potential strategies. We aim to identify the most efficacious organisms, rates and timings of application for sustainable pest management. The challenge remains to identify a natural enemy that will actively forage and feed at low temperatures. We will evaluate lacewing larvae (Chrysopa carnea) and ladybeetle larvae (Adalia bipunctata) targeted to control aphids, and two predatory mite species that have been suggested to forage at lower temperatures to control spider mites (Amblyseius andersoni and A. californicus). In addition to natural enemies, we predict that bacterial and fungal biopesticides are an efficacious pest management tool in this system. The low temperatures and relative humidity inside the tunnels and under the floating row covers will likely promote their efficacy in managing pests. We will examine Chromobacterium substugaea strain PRAA4-1, Isaria fumosorosea Apopka Strain 97, and Beauvaria bassiana products. Efficacy trials will be carried out in a randomized complete block design across multiple high tunnels at the Meigs Horticulture Farm, with and without floating row covers within each high tunnel. 

Identification and management of an emerging strawberry disease caused by Pestalotiopsis (Neopestalotiopsis) spp.

Our working hypothesis is that strawberry varieties differ in susceptibility toward the new strawberry disease. Correct identification and timely spray of biological or synthetic fungicides can effectively control this disease.

Approach: The incidence and severity of the disease will be compared among varieties evaluated in the open-field low-tunnel system as described in Objective 1. Representative symptoms of the disease caused by Pestalotiopsis will be closely documented and separated from other strawberry foliar diseases. Separate efficacy trials will be conducted in the greenhouse at SWPAC with representative bare-root and plug strawberry cultivars to determine the relative susceptibility of cultivars to Pestiolopsis. A susceptible cultivar will be chosen to evaluate organic and conventional fungicides, including but not limited to the conventional active ingredients fludioxanil and captan, and alternative products such as Double Nickel, Lifegard, Regalia and Serenade.

Objective 3. Establish scale-appropriate budgets for the strawberry production systems based on data collected from research- and on-farm trials.

The overall goal of the objective is to understand the economic feasibility of the proposed strawberry production systems on small and diverse farms.

Approach: Costs associated with establishing and implementing strawberry production systems in Objective 1 will be documented at all research locations in Years 1 and 2. In addition, in Years 2 and 3, we will identify four to six farmer collaborators in Indiana or Ohio for on-farm demonstration of the production systems. Collaborating farmers will use the production systems suitable for their unique situation for growing strawberries. Collaborators will be expected to keep records of production practices, collect yield information, record material costs and time spent on managing and harvesting the strawberries, and gross income from selling the strawberries. The grant will reimburse the cost of strawberry plants and compensate farmers for time spent on collecting yield data. Using information provided by the collaborating farmers as well as information generated from research trials, we will develop budgets for each of the systems. These budgets will include and compare IPM strategies evaluated in Objective 2. Our team, composed of farmers and extension professionals, are highly experienced in developing such budgets. Nevertheless, to supplement our knowledge, we will also consult agricultural economists at Purdue University and The Ohio State University.  

Objective 4. Develop a comprehensive production guide to facilitate the adoption of strawberry production in the NCR using alternative systems.

The overall goal is to develop a comprehensive and interactive production guide for growing strawberry using alternative systems. The production guide will cover information on production practices, including but not limit to, variety selection, growing media selection, fertility management, disease and insect pest management, microenvironment management, budgets, and marketing.

Approach: The project team will work closely with farmer collaborators to develop the production guide. Initial information will be collected through research and on-farm trials. We will also review existing strawberry publications in the U.S. and abroad, including publications from Asian counties where strawberry production is primarily conducted in tunnel systems. Information will be adjusted to fit specific conditions in our region. Literature reviews and research results generated from this project will be summarized in the guide. Case studies and farmer testimonials will be included. The production guide will also link to external resources that farmers can consult for additional information. In addition to providing data collected from on-farm trials and shared experiences, collaborating farmers are expected to contribute to the development of this product.

We expect the educational publication will be delivered as an interactive book that includes articles, diagrams, pictures, and videos. It will be available for free download from Purdue Extension Education Store. A separate but related video series to demonstrate technical components of the project will also be created and shared publicly. The project team will promote the production guide through multiple extension networks. 

Participation Summary
2 Farmers participating in research


Educational approach:

Field experiments aiming to increase strawberry yield and quality and extend the harvest season are carried on at three research locations (Southwest Purdue Ag Center in Vincennes, IN; The Ohio State University South Centers, Piketon, OH; Tanglewood Berry Farm, Fort Wayne, IN). These multi-locational experiments focus on three strawberry production systems, i.e., soil-based high tunnel system, table-top high tunnel system, and soil-based low tunnel system (Obj. 1)

Additional experiments are conducting at Meigs Horticulture Research Farm in Lafayette, IN, to monitor the seasonal abundance of insect pests in the high tunnel system and to develop management recommendations focusing on augmentation biocontrol and application of biopesticides. Greenhouse experiments were conducted to improve understanding and management of the emerging strawberry disease caused by Pestalotiopsis (Neopestalotiopsis) spp. (Obj. 2)

On-going on-farm demonstration trials will enhance our understanding of the system challenges and economic feasibility in real-farm situations.


Project Activities

Strawberry Field Day
Soil based high tunnel production system on-farm demonstration
A Midwestern Perspective on a New Strawberry Disease Caused by Neopestalotiopsis spp.
Local strawberry production with alternative production systems
Strawberry production in high tunnel
High tunnel strawberry production: Opportunities and challenges
Plasticulture Strawberry Crop Status: Are Additional Protections Needed to Encourage Fall Growth?
Applying Row Covers for Winter Protection in Plasticulture Strawberry Production
Strawberry Pests Observed in 2022 Season
Is it Okay to Propagate Your Own Strawberry Plug Plants?
New Strawberry Disease

Educational & Outreach Activities

20 Consultations
3 Journal articles
3 On-farm demonstrations
5 Published press articles, newsletters
5 Webinars / talks / presentations
1 Workshop field days
1 Other educational activities: Podcast Strawberry Chat

Participation Summary:

500 Farmers participated
50 Ag professionals participated
Education/outreach description:

We have or will publish experiment results in peer-reviewed journals or extension publications. We developed a Strawberry Chat Podcast to discuss strawberry production-related topics. A field day highlighting this project was conducted in May 2022 at Southwest Purdue Ag Center. We regularly updated project progresses through newsletter articles.  A comprehensive production guide summarizing all we have learned in the project will be developed toward the end of the project, providing farmers with a readily available tool for growing strawberries. (Obj.3) 

The newsletter articles and presentations were listed under Project Activities. The published journal articles were included in Information Products. 

Information Products

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.