- Day-neutral strawberries have a longer harvest season and higher overall yields than June-bearing strawberries.
- They yield best when grown on plastic mulch but can be grown on other mulch types.
- They are usually grown under low tunnels but can also be grown in caterpillar tunnels, high tunnels or tabletop systems.
- They can be grown successfully on both organic and conventional farms.
- UMN research has allowed us to learn a lot about how to grow day-neutral strawberries successfully and sustainably in the upper Midwest.
Day-neutral strawberries have different growing requirements than June-bearing strawberries:
- They are grown as annuals.
- They are typically grown under protected culture (low tunnels, high tunnels).
- They are harvested for a longer season.
- They have higher yields.
- They require more maintenance throughout the growing season.
Day-neutral varieties are not sensitive to day length, which means the plants flower and fruit continuously when temperatures are moderate. Because of this, day-neutral varieties typically produce fruit from July through October or until the first killing frost.
June-bearing strawberries, on the other hand, form flower buds during the short days of fall. These buds complete their development and bloom the following spring, which is why they produce fruit during a short window in late June to early July.
Day-neutral strawberries are commonly grown under low tunnels, though this is not required for successful production. Low tunnels are thoroughly tested and found to be the most effective method for growing day-neutral strawberries. Caterpillar tunnels and high tunnels can also be used, but these cost more than low tunnels.
Whichever system you choose, protected culture will increase the season length and greatly reduce disease compared to open-field conditions.
Most day-neutral strawberry varieties grow best between 45°F and 85°F. The plants stop growing in temperatures lower or higher than that range.
Strawberries have shallow root systems, so during the summer when temperatures can be over 85 degrees, finding ways to cool the plants may improve flower initiation and thus fruit production. University of Minnesota research trials have found that white on black plastic mulch performs well for this purpose.
Day-neutral strawberry varieties
A growing number of day-neutral varieties are available for production in Minnesota. The varieties below have been compared in University of Minnesota trials under low tunnels and in open fields. Variety performance will vary from farm to farm. Before committing to one or two varieties, experiment with several to determine which are best for your site.
- San Andreas
Generally, day-neutral varieties are just as sweet as June-bearing varieties. San Andreas and Albion were found to be the sweetest in UMN trials. Portola had the highest yields but was the least sweet of the six varieties tested. However, all varieties tested are relatively sweet.
Planting and setting up low tunnels
Day-neutral strawberries require the same soil and sites as June-bearing cultivars. Plant them in the early spring, at the same time as June-bearing cultivars.
If a bed shaper is available, plant on a 6- to 8-inch tall raised bed as shown in the videos above. The raised bed provides higher spring soil temperatures and better drainage, allowing faster establishment and earlier harvest.
Using a plastic layer attachment, cover the beds in white-on-black plastic. University of Minnesota research has found that day-neutral strawberries yield best on white-on-black plastic. The strawberries have lower yields when grown on straw. Landscape fabric can potentially work for some growers, but it carries logistical challenges such as removing, cleaning and re-using the fabric from year to year.
Plant the strawberry plants into 2 rows per bed. The rows should be 8 to 12 inches apart with 8 to 12 inches between plants within the row. Day-neutral varieties can also be planted in single rows 3 feet apart with plants 6 to 9 inches apart in the row. Multiple rows per bed bring higher yields per acre than single rows. Leave 18 to 24 inches between each bed to allow for movement of pickers and equipment.
In the inter-row spaces, lay landscape fabric, plant a cover crop or leave the soil bare. UMN research found that test plots with landscape fabric between rows had higher yields than plots with cover crops between the rows. This is likely because the plants are sensitive to competition for water and nutrients (see video below).
Managing day-neutral strawberries
- Remove flowers from day-neutral plants for four to six weeks after planting to encourage vegetative growth. When plants have developed five or six expanded leaves, they should be allowed to flower.
- Remove runners throughout the season to encourage greater fruit production.
- Harvest every 1 to 3 days. Harvesting every 1 to 2 days decreases spotted wing drosophila (SWD) infestation and increases marketable yield.
- Manage weeds between the rows by mulching between the rows, hand-weeding and hoeing. Cover crops may be used between the rows, but they will not necessarily outcompete weeds unless vigorous varieties are planted at high seeding rates.
Year before planting:
- Plan project: 2nd week of April through mid-June
- Site selection: Early June through July
- Incorporate compost and other nutrients: September through late October
Planting and production year:
- Tilling to prepare for bed formation: 2nd through last week of April
- Form beds, lay drip tape, punch plant holes: First 2 weeks of May
- Lay landscape fabric between rows: First 2 weeks of May
- Planting: Last 2 weeks of May
- Construct tunnels: Mid May through the first week of June
- Control weeds: Mid May through late October
- Remove flowers: Last week of May through end of June
- Remove runners: July through mid August
- Harvest berries: Mid July through late October
- Deconstruct tunnels and beds; prep for next year: End of October through December
Day-neutral strawberries have high nutrient demands because they fruit throughout the season while also growing vegetatively. Nutrient management is achieved through soil applications before planting, and fertigation to add nutrients during the growing season.
- Before planting, incorporate P, K, and part of the total nitrogen.
- Then, use fertigation to apply the rest of the total recommended N rate in 4 to 6 applications at intervals throughout the season.
- Base rates on the percent of organic matter on the soil test report.
- Soils with lower organic matter have higher annual nitrogen needs (see table below).
- Base your phosphorus and potassium applications on soil test results as well.
- Use soil tests and annual foliar analyses to determine whether micronutrient applications are necessary. Routine micronutrient applications are not necessarily beneficial and should only be applied if indicated by foliar testing.
Day-neutral strawberries are typically grown as annuals. Some growers choose to overwinter them, although they are not as productive in the second year.
Irrigation, fertilizer application and pest control during the second year are similar to the first year.
Cover the plants with straw in late fall, following recommendations for June-bearing strawberries; they can succumb to winter injury at or below 12 degrees F.
You may need to use spring frost protection measures in the late spring.
Marketing day-neutral strawberries
Growing Day Neutral Strawberries for Market (Webinar recording: 00:59:51)
UMN research on day-neutral strawberries
University of Minnesota researchers have been refining day-neutral strawberry production recommendations for Minnesota through several years of research. Past and current projects include:
- Biodegradable mulches
- Between-row cover crops/living mulches
- Low tunnel vs. open field production
- Testing table-top strawberries in the upper Midwest
- Planting borage to attract pollinators to berries
To read the most up-to-date information about this research, visit fruit.umn.edu.
Fruit and Vegetable blog: Want to Try Day Neutral Strawberries?
Reviewed in 2021