Testing tabletop strawberries in the Upper Midwest

August 24, 2020

       

strawberries growing in raised troughs

       

By
Nathan Dalman

Looking beyond day-neutrals

Day-neutral strawberry varieties have already greatly extended the Minnesota strawberry production season that was traditionally from June into July to July through October. However, this extended season has also come with new challenges such as soil borne diseases and insect damage that typically occur later in the growing season. These issues were not as prominent during the traditional strawberry production season. One way we can address these problems is by exploring new production systems with the goal of making production less labor intensive while still producing high quality fruit in a more sustainable way.

Getting up off the ground

During the 2020 and 2021 growing seasons, we are exploring a tabletop growing system for day-neutral strawberries. Plants are grown in troughs which sit in a gutter that is raised several feet off the ground, about waist height, which is where it gets the nickname “tabletop”. This raised growing system will not have the production challenges of weed control or soil borne diseases. The system produces very clean fruit that is harvested quickly and easily. A gutter system also allows for early planting of the strawberry plants as you are not dependent on soils drying out and warming up. Another benefit of this raised gutter system is that it can be installed on marginal land that wouldn’t normally be used for agriculture. The only requirement is that it must be located near a water source that is appropriate for irrigation. This system will allow new producers to get started in strawberry production who wouldn’t normally have the land to produce berries, which will result in more locally grown strawberries.

A closer look at our research

Now, to get into the specifics of the project. Trials are taking place at West Central Research and Outreach Center in Morris, MN and at the UMN St. Paul Campus. At both of these sites we are testing two different growing substrates, one is organic and one is not. These substrates are primarily composed of peat moss. There are 12 troughs filled with organic substrate and 12 with non-organic substrate. Each trough is 3 feet long, 6 inches deep and contains 9 plants. In addition to trialing two media, we are also using two day-neutral strawberry varieties, Cabrillo and Albion.

strawberry plants growing in a plastic trough
Each trough is filled with soilless substrate and contains 9 plants. In this image, the trough is sitting on the ground for demonstration purposes. For production, all troughs are placed in a raised gutter system as shown in other photos.  ​​​Photo by Nathan Dalman.
In addition to the UM trial sites, our team consists of two farmer-cooperators trying the system: one site near Garfield, MN and one near Farmington, MN. The site near Garfield only has non-organic substrate and the one near Farmington only has organic substrate. These two farmer-cooperators are trialing 6 varieties: Cabrillo, Albion, Monterey, Mara de Bois, Seascape and Evie II. These producers will take observational data on which varieties seem to perform well in this new growing system, and will also share information about the system with other producers. 
 
strawberries growing in troughs on a raised gutter system
The raised trough system includes a band of white trellis tape which supports the berry trusses (the stemlike structures that form the berry clusters). This prevents damage to the trusses and also makes harvesting easier because the berries are supported rather than hanging down below the gutter. Photo by Nathan Dalman.

Precise irrigation and fertilizing

Since the strawberry plants have a limited root system in the troughs, they must be regularly fertilized to maintain plant health and production. This is done using a fertigation system that adds a small amount of fertilizer each time the plants are irrigated. The injector takes the fertilizer solution and injects it to the irrigation lines. The irrigation system provides water and nutrients directly to the plant’s roots as shown here. 

 

fertigation system for tabletop strawberries
The injector draws a fertilizer solution from the bucket and adds it to the water that flows through the main irrigation line (left). The main irrigation line is the larger tube hanging on the side of the gutter (right). Smaller tubing then connects the main line to the trough ensuring proper placement of water and nutrients to the plants' roots. Photos by Nathan Dalman.

Goals of our research

Overall, the objectives of this project are to determine:

  • If the raised growing system is feasible in Minnesota.
  • If the system can be used by both organic and conventional farmers.
  • How well the different varieties produce in this new system.

We have just recently started harvesting berries from this system, and we’re excited to update you with our findings!

 

row of tabletop strawberries
Tabletop strawberries can be grown in areas that may not be suited for traditional agriculture. Photo by Nathan Dalman.

Acknowledgements

Thanks to project personnel Steve Poppe, Dr. Emily Hoover, Dr. Neil Anderson, Lindsey Miller, Emily Tepe, Dr. Andrew Petran of Twin Cities Berry Co., and Jeff and Jane Way of Ida Valley Farm.

This project is funded by the Minnesota Department of Agriculture and made possible through the University of Minnesota West Central Research and Outreach Center and Department of Horticultural Science. Thanks to JR Peters, Inc. for supplying fertilizers, Berger Horticultural Products for supplying the growing media, and Meteor Systems for supplying the materials necessary for building this growing system.

Mention of particular businesses or products does not imply an endorsement by the University of Minnesota, but is intended for informational and acknowledgement purposes only.