Final report for FNC19-1188
1.5 acres of organic day-neutral strawberries and 0.1 acre of organic raspberries in high tunnel. We are entering our 3rd field season in 2020. Our primary sustainability goal is to work towards a zero-spray operation while maintaining economic sustainability.
Demand for local, organic fruits is increasing throughout the United States. For strawberries in the Midwest it is difficult to meet this demand with a concurrent supply; this is due to the short harvest window of June-bearing fruit grown in the region. Organic production of day-neutral strawberries with vastly extended harvest windows is growing in the Midwest, and has potential to meet this increased demand for local and organic fruit available almost year-round. However the practice is still in its infancy. Little is known on how to properly and sustainably produce day-neutral strawberries over an extended season exposed to a longer buildup of pest, disease and weather pressures unique to this region. We propose a comparison of the yield, quality and harvest windows of two strawberry management practices: a raised bed, plasticulture system managed with a traditional organic spray regimen in the open field, versus a similar raised-bed system equipped with exclusion netting to provide a physical barrier for pests and allow reduced chemical inputs. A thorough yield and quality comparison will allow us to determine if a protected culture system can produce profits and harvest seasons high enough to justify the increased initial costs.
- Compare the yield, quality, harvest window and profitability of an exclusion vs organic spray system for day-neutral strawberry production.
- Evaluate and discuss the ecological and economic impact of each system by recording the spray regimen of the pesticide treatment and comparing its cost vs the installation of exclusion netting.
- Continue TCBC’s mission of open-source farming by sharing project findings via conference presentations, website blog updates and social media interaction.
This one-year research/demonstration project will comprise of two equal-size insect management treatments: an open field treatment using a traditional organic spray regimen (Figure 1a) and an exclusion netting treatment, held up with bent pipes in a hoophouse-type structure (Figure 1b). Each treatment will be 0.5 acres and consist of 9 raised beds of 380′ length and 5.5′ bed spacing. The exclusion netting will cover the strawberries in the tunnel treatment after strawberries are planted, to accommodate tractor and bed shaping equipment (Figure 1c). Finally, mason bee pollinators will be introduced to the exclusion treatment to accommodate the perpetual flowering nature of the strawberry plants.
We will record weekly yield (lbs), quality (grade A vs. grade B fruit) and harvest duration (# of weeks) of strawberry fruit, compared between each treatment. Data will be analyzed in the winter of 2019-2020 with updates throughout the season via farm website blog updates (www.tcberries.com), social media (Instagram @twincitiesberry and Facebook) and field days upon request. Raw data for the project will also be made available upon request.
Spray regimen for the open field treatment will be recorded as well. Total cost of sprays will be calculated and incorporated into final analysis and discussion. Data analysis topics will heavily focus on profitability comparisons between systems, such as ‘total cost of each treatment’, ‘yield and fruit quality differences between treatments’, ‘estimated time that decreased sprayings and increased quality will pay for the cost of exclusion system’. A discussion of the environmental benefits of reduced spraying will be incorporated as well. Final data analysis, results and discussion will be distributed online and via conference presentations (SFA, MFVGA, MOSES etc.) in the winter of 2019-2020. Dr. Petran has already been asked to present at the 2020 Hort Night in Morris, MN and will incorporate results from this project.
Yield– Weekly total and cumulative yields were higher in the netting treatment throughout the entirety of the 2-year project. The figure shown here summarizes the comparative yields for each treatment separated by year. Fruit quality was also greater, both in total amounts and proportionally, in the netting treatment compared to the open field, as seen here.
Sprays– In both 2019 and 2020, Sprays were conducted 2x/week in the open field plot over the course of the recording period, compared to 2x/month in the net, for a total annual spray event reduction of 14 under the net. In addition to the benefit of this reduction to native pollinators, it also resulted in a reduction of approximately 42 oz. of pyganic 5.0 per year, saving nearly $200 of annual field expenses.
Financials– 2020 harvest data revealed that netting production yielded 272% more fruit over the course of the 8-week recording period than open field production, which in the case of our trial equated to approximately 700 more pounds of fruit. Depending on markets and demand this can result in a revenue increase of $4,000-$5,000, meaning that combined with savings from spray reductions the cost of the netting system would pay for itself within 2 years and quite possibly within 1 year. Consideration must be made that this was only over the course of the recording period and not the entire harvest season, so the real advantage is possibly even more.
Educational & Outreach Activities
- July 25, 2019- Horticulture Night, West Central Research and Outreach Center, Morris, MN. Discussed the netting system and project during a presentation with Steve Poppe. Estimated 70 audience members over two 45-minute talks.
- August 28, 2019- YouTube video on The Young Berry Farmer channel about the netting structure, titled “Do You Use CHEMICALS on Your Farm?” A discussion on sprays and my efforts to reduce them on my farm”. 60 views as of this report.
- Oct 1 2019- ON-farm meeting and tour with Annie Klodd, research and extension educator at the University of Minnesota. This meeting has led to the netting system being discussed at several UofMN Extension meetings and an invitation to speak with Annie at the 2020 MOSES conference about netting control for SWD, where this project will be discussed. Estimated grower/farmer attendance 200.
- January 16-17 2020- Conference presentation at the Northern Growers and Marketers Conference in St Cloud, MN. Will discuss and credit the netting project in a co-presentation with Dale-Ila Rigs of Berry Protection Solutions. Estimated grower/farmer audience 50.
- June 2019-present. Consistent updates about the construction, management and status of the netting project on the Twin Cities Berry Company Instagram account. Several hundred unique post views to date.
- Feb 2020- Conference presentation with Annie Klodd at 2020 MOSES Organic conference, “How is SWD changing the way we grow berries?” Estimated attendance, 200
- August 20, 2020- Insect Netting for Spray-Free Pest Control on Fruits and Veggies, YouTube video published documenting the construction and benefits of netting system funded through this project. Views as of Jan 25- 46.
Much was learned after the first year of this grant project, but can be most easily summarized into two categories:
- Construction and Maintenance of mobile, low cost netting structure. The advantage of the netting system proposed was twofold- one, that it is significantly cheaper than other protected culture options, like high tunnels, and thus more financially accessible for farmers, and two, that it is fairly modular/mobile, meaning that it can be removed at the end of the season for storage and protection from MN winters, and also be placed in a new location in subsequent field seasons, allowing the system to “move with production” in an annual rotation system. This is also something high tunnels cannot do easily or at all. The learning experience came from how to construct and maintain the netting system, as there are no readily available online resources, manuals, videos or toolkits for this relatively new process. It took two weeks (on and off, of course) to put up the initial structure in mid-June, consisting of PVC support poles placed into the ground, with endcaps on top and poly-wire stringing from pole to pole, making a raised grid system to support the relatively light and porous net. Unfortunately, the literal day after the net was completed, the farm experienced it’s strongest windstorm of the season, with gusts over 60MPH. This blew down the net structure. It was a bad day for morale. However, after a few hours of pouting I got to work on improving the system. After the blowdown, I secured the perimeter poles with rope tied to anchors or fenceline, and further secured the four corner poles with multiple anchors in different directions. After this adjustment, the net structure never blew down again. Unfortunately, I had to reduce the size of the net treatment to a 1/4 acre due to damage to the netting from the windstorm that could not be quickly fixed. Therefore, the adjusted project became comparing total and marketable yields of a 1/4 acre net plot to 1/4 open field plot, as opposed to the originally proposed 1/2 acre plots. In 2020 I believe we will be able to move back to 1/2 acre. In the future, I believe a stronger system would use stainless steel support poles, placed 32″ into the ground, instead of PVC. With this stronger support, I doubt that strings and anchors would even be needed.
- Performance of fruit grown under netting structure vs. open field. Day neutral strawberries grown under the netting structure performed incredibly well compared to the open field control. Please refer to these figures: https://imgur.com/a/YEYwuNY I learned that total yields and ratio of grade A : grade B fruit were considerably higher under the net treatment, both cumulatively and in every individual week of comparison, totaling 2 months. After week 8, harvest no longer occurred in the open field due to pest and disease pressures, but continued within the net for several more weeks. I estimate that the increase in yields under the netting system over the open field will be enough to pay for the cost of the netting within two years. There were also zero spray events within the net, opposed to weekly and sometimes twice-a-week sprays in the open field treatment, totaling a 15 to 0 comparison of spray events in the open field and net plots, respectively. Due to these observations, I learned that day-neutral strawberry production within a net environment appears to be beneficial for both economic and environmental aspects of sustainability.
After presenting at multiple conferences and discussing with farmers, the response for the system in general is mixed. While many farmers see the benefit of insect netting and have contacted me asking for where to procure netting for their own farms, others have the feeling that the netting system wouldn’t work on their operation, though cannot articulate why. Still other farmers feel confident in investing in other, less thoroughly researched or proven SWD management practices for their small fruits. I believe that as time goes on and this practice becomes more adopted it will decrease general apprehension of implementation.
Since receiving this grant I was also funded through the MDA Researcher and Demonstration Grant. In this new grant I am testing the productivity of the netting structure against a more controlled protective “hybrid” system that also includes poly to reduce fungal pressures inside the exclusion environment. This project will begin in earnest in 2021.
Discussion of the system was warmly received by many farmers at the MOSES Conference in 2020. I have been contacted by several sources asking for my netting source, as farmers are now considering incorporating physical exclusion practices onto their farms. I anticipate continuing to strengthen the exclusion system annually and discussing/optimizing practices with other farmers who incorporate netting systems onto their own farms.
The netting system has, so far, been an incredibly useful tool for increasing harvest season, total yields and % marketable yields for day-neutral strawberries at a relatively low cost compared to other protected culture systems, like high tunnels. However, while almost completely eliminating pest pressures, the nets do relatively little to fend off the considerable disease pressures that are mounting in the face of increasingly rainy field seasons. A modified system that excludes both pest and disease pressures would help increase yields/economic viability of small fruit operations in our region without relying on chemical sprays. A simple structure with a poly top and netted sides would likely do the trick. Indeed, in 2021 I will be testing this system out against the traditional netting enclosures through a grant secured from the Minnesota Department of Agriculture.