An integrated approach to developing a day neutral strawberry production industry

2006 Annual Report for LNE06-241

Project Type: Research and Education
Funds awarded in 2006: $88,700.00
Projected End Date: 12/31/2010
Region: Northeast
State: Maryland
Project Leader:
Willie Lantz
University of Maryland Extension

An integrated approach to developing a day neutral strawberry production industry


Strawberry producers in the eastern United States primarily use spring bearing cultivars, which produce a crop for a relatively short period of time. Harvest is finished by the end of June; however, with large urban populations nearby, the demand for fresh strawberries is strong throughout the summer. Until recently the small size and poor quality of day neutral strawberry cultivars have prohibited day neutral strawberry production from filling a portion of this market. Many growers are looking for ways to produce fruit during the summer months to meet the demand by the consumers.

This project will introduce farmers to new varieties of day neutral strawberries, which have the potential to produce heavy yields of fruit with very desirable flavors. Potential producers will be invited to yearly field days, have the opportunity to attend a strawberry short course, and participate in monthly field walks during the growing season.

As a result of this project, growers will have information on the best nitrogen fertilization levels, plant propagation methods, growing techniques and variety selection. During the first year of the project organic nitrogen (compost) and nitrogen levels will be evaluated to determine which level will produce the highest marketable yields and healthiest plants. In the second year of the project, growers will evaluate the best method of propagating day neutral strawberry plants. In the final year of the project, growers will evaluate new varieties in variety trial plots.

Potential producers will be invited to attend annual field days held during each of the three years of the project. Of the 200 potential producers that will attend a field day, 100 will attend a strawberry short course or field walk to further their knowledge of growing day neutral strawberries and 20 will plant day neutral strawberries utilizing new varieties and production techniques. Surveys will be conducted to determine that milestones have been reached.

Objectives/Performance Targets

The primary outcome of this project will be to establish a day neutral strawberry production system in the cool climate areas of the northeast. Information gained through this project will be presented through field days, yearly strawberry short courses, and field walks held during the growing season. 200 farmers will attend field days on growing day neutral strawberries. Farmers who have interest in producing fruit will be invited to attend a yearly strawberry short course or field walks. 100 farmers will attend a second educational event such as a strawberry short course or field walk. Of the farmers that attend the field walks or strawberry short courses, 20 will add day neutral strawberries growing new varieties utilizing advanced growing techniques to their farming operation. All participants of the short courses and field days will be surveyed to determine who has added day neutral strawberries to their farming enterprises.


During 2006, the project established two research plots (one in Garrett County, MD and the other at Penn State’s Horticulture Farm at Rock Springs) to examine the nutrient needs of annual planted day neutral strawberries. Each site looked at nine nutrient levels created by overlapping three levels of compost (0, 40, 80 pounds of available nitrogen) and three levels of nitrogen applied through drip irrigation (0, 1, & 2 pounds of soluble nitrogen each week). Each plot contained three reps in a split block design. Dormant cold stored ‘Seascape’ day neutral strawberry plants were planted in 32 cell trays and were started in a greenhouse. The plants were held at 10 degrees C until planting time. The plants were planted into a raised bed which was covered with an aluminized plastic. Aluminized plastic was selected to keep the soil as cool as possible during the growing season. Flowers were removed on the plants until the middle of June to promote plant growth. Fruit harvest began the first part of July and continued until frost the middle of October. Berries were harvested three times weekly and the number of berries were counted to determine size. Leaves were harvested four times during the picking season and analyzed.

We were successful in establishing an annual day neutral strawberry planting that produced fruit from July through mid October. Fruit production ranged from .4 pounds of fruit per plant in Maryland to 1.2 pounds in PA. This production is comparable to the production levels in Canada and slightly less that those in the United Kingdom. The average fruit weight at the Pennsylvania site was 11.7 grams for marketable berries and 10.6 for all fruit at the Maryland site.

In the nutrient study, no overall statistical difference was achieved when the results of both locations were combined between the nine nutrient levels. At the Garrett County site, a statistical difference occurred on the soluble fertilizer dripped through the irrigation. The 2 pounds of soluble nitrogen level produced .58(a) pounds of fruit per plant, the 1 pound of soluble nitrogen level produced .51(ab) and the 0 nitrogen level produced .44(bc) pounds of fruit per plant. The number of berries produced was also significantly different with the 2 pounds of soluble nitrogen producing 1014(a) berries, the 1 pound of soluble nitrogen producing 906(b) berries, and the 0 level produced 794(c). The leaf analysis regression results using SAS PROC Stepwise MaxR improvement (r2=0.18,p(F) = 0.0004) in the best 4-element model for yield per plant yielded a significance for nitrogen (0.02) and potassium (0.01). This indicates that the statistical difference in yield was likely a result of the varying the amount of nitrogen and potassium. These two nutrients are important for plant growth and fruit sugar accumulation.

The research plot at Penn State was featured as part of the biannual Penn Sate Fruit and Vegetable Field Day. A field day held at the Garrett County site explained the research to 13 participants. Data from the 2006 project was also presented at the 2007 Northeast Region American Society for Horticultural Science meeting and the 2007 Mid Atlantic Fruit and Vegetable Conference.

Impacts and Contributions/Outcomes

The 2006 research project has provided valuable information for local producers. The yields achieved at both sites for the annual production system were adequate to provide for a profitable enterprise. By producing fruit during the summer months, local producers should be able to achieve prices such as $3.00 per pint which results in an income of about $1.50 per plant. At a cost of about $.50 per plant, producers should make a profit equal to about $15,000 per acre. Hopefully future research with different varieties will give higher yields providing for higher profits. In this year’s project, no pesticides were required for disease control.

At the field day held at the Garrett County site, 9 participants completed a survey. Of those surveyed, 6 out of 9 were not currently raising any type of strawberries. On the survey participants were asked “After attending this field day rank how the field day helped your understanding of day neutral strawberry production. On a scale of 1 (Not helpful) to 5 (Very Helpful), the average response was 4.3. The participants at the field day and at a High Tunnel Twilight Meeting were asked if they would be interested in participating in a group order for day neutral strawberries to be planted in an annual system. A large number indicated they were interested. The type of plant used in the annual system (large plug plant) cannot be ordered from an existing supplier. We have made arrangements with a local greenhouse to get the plants in February and prepare them for plug planting in the spring. We currently have 15 people who have ordered 200+ plants each and a total of nearly 20,000 plants (enough for 1.3 acres).


Harry Swartz

[email protected]
Associate Professor - Small Fruits
Univeristy of Maryland
2102 Plant Science Building
Univerity of Maryland
College Park, MD 20742-4452
Office Phone: 3014054337
Kathleen Demchak

[email protected]
Small Fruit Specialist
Penn State University
107A Tyson Building
University Park, PA 16802
Office Phone: 8148632303