I have a question about hoop house strawberries, especially elevated beds with various substrates. Can someone help?

J.D.IdahoAnswer: Your research request suggests that you are primarily interested in hydroponic strawberry production. Hydroponic means that a non-soil based medium is used as a substrate and fertilizer and pest control happens through the irrigation system. If this is the case in your situation, perlite is a common medium used for hydroponic strawberry production. Since the substrate is typically expensive as is the nutrients, the bed width is kept to a minimum and alternative containers are typically used.A study published by the USDA-Agricultural Research Service describes a few different hydroponic strawberry production systems and suggests a few varieties that work well in a hydroponic system. One of the systems is a vertical system of which they have the following suggestion. “Light intensity greatly affects strawberry growth and development. Since light levels reaching the plants at the lower section of the towers were only 20 percent of levels measured at the top, fruit production was reduced. Slightly taller pots spaced farther apart on the towers would reduce this problem.” They also describe a system that is initially capital intensive, but has the potential to bring high returns. This research report is available online at the following link:Hydroponic Strawberries Avoid Soil PestsBy: Doris Stanley; November 1998; Agricultural Research magazineAnother study on hydroponic strawberry production showed that certain varieties yielded well under hydroponic conditions and were less susceptible to powdery mildew and aphid predation. In this study they did not use fungicides or pesticides and had yields that were almost 2x greater than field grown strawberries. They outline the advantages and disadvantages of greenhouse culture in this publication:Advantages:

  • Soil fumigation in not required.
  • Yields per acre up to five times greater than field grown
  • Quality of fruit is increased
  • Grey mold and anthracnose are not a significant problem
  • Fruit can be produced and marketed as pesticide-free.
  • Harvest efficiency can be improved by 25-30%
  • Production is increased during the early season.

Disadvantages

  • Start-up costs for greenhouse production can be high.
  • Grower knowledge deficit. Growers are skilled at highly intensive fieldproduction; they must adapt their skills for greenhouse production

The study, “Protected Culture of Strawberry as a Methyl Bromide Alternative: Cultivar Trial,” by: Ashwin V., et al. 2003 can be viewed online in the embedded link. [PDF/34K]PVC strawberry production is a hydroponic system using large (4″ or greater) PVC pipes cut in half to make troughs to hold the substrate and plants in. Below I have listed a publication that describes the PVC Trough system among other systems complete with pictures and substrate information for a hydroponic situation. They also looked at different substrates to plant the strawberries in?peat mix, perlite, and pine bark. All of these substrates yielded virtually the same, which is not surprising, as all of the nutrients in a hydroponic situation are from the hydroponic solution (Paranjpe, A., et al. 2003). Winter Strawberry Production in Greenhouses Using Soilless Substrates [PDF/285K]By: Paranjpe, A., et al. 2003. If hydroponic production is not your intention, below is a great overview by a horticulture specialist at Cornell University who specializes in greenhouse berry production. Berried Treasures: Off-Season Production of Strawberries and RaspberriesBy: Marvin Pritts – Department of Horticulture. Cornell University. 2000. If you are particularly interested in organic strawberry production it is important to consider fertility management for organic strawberries. For sustained organic fertility throughout the season (which is what an everbearing will need,) a common practice is to apply enough high-N materials, such as fish meals, seed meals or alfalfa meal, to supply 30 pounds of actual N per acre. Compost can be used as a supplement and serves well to condition the soil and balance nutrients but does not provide enough available N at the time needed. An inch of compost and the appropriate amount of a high-N organic material spread directly over the rows is recommended (Sideman 2002). For information on organic hydroponic nutrient solutions see the further resources section below for Mary Peet’s power point on the topic.