Winter Raspberry Production in an Earth Contact Solar Greenhouse.

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2010: $6,000.00
Projected End Date: 12/31/2012
Region: North Central
State: Missouri
Project Coordinator:

Annual Reports


  • Fruits: berries (brambles)


  • Crop Production: continuous cropping
  • Education and Training: farmer to farmer
  • Energy: energy conservation/efficiency, energy use, solar energy
  • Sustainable Communities: local and regional food systems, sustainability measures

    Proposal summary:

    The Winter Raspberry Production in an Earth Contact Solar Greenhouse project will focus on two main problems. The first problem is the unprofitability of small-scale winter production in a conventional greenhouse. The rising cost of fuel makes small scale winter greenhouse production unprofitable. A conventional greenhouse in northwest Missouri can only operate without supplemental heat from mid-April to late-September. It is difficult for small-scale producers to incur enough income during this short, 5 1/2 month period to cover the 12 month expenses of the structure.

    An Earth Contact Solar Greenhouse (ECSG) could be used to extend the season, but very little research has been done on this topic in the U.S. Overseas trials and active production have shown that the use of solar radiation and soil heat banking can maintain daytime temperatures into the 80s and nighttime temperatures in the 50s. This environment is ideal for raspberry production. In this trial, an existing high tunnel frame will be converted to an ECSG. Potted fall (primocane) raspberries will be moved into the ECSG in early October before the first fall frost. This will extend the season of these ever-bearing brambles into November. At that time, the tips will be pinched causing side branch growth and more fruit; hopefully, extending the season even further into December. This will potentially add three months to the greenhouse growing season.

    A second and third set of potted spring (florocane) raspberries will be left outside after the first frost and until daily outdoor temperature recording shows that they have accumulated their required 1000 chilling hours. Historical weather data shows this should be in early January. At this time, the raspberries can be moved into the warm ECSG and forced for early spring production. The first set should begin producing fruit by March and continue into April. The second set will be brought in so that they begin production in April and continue into May. This will extend the greenhouse growing season an additional 3 1/2 months (mid-April through May already accounted for in paragraph 1). Successful production in an ECSG could extend the greenhouse growing season by 6 1/2 months (Oct to mid-April), thus establishing a profitable system for year round small-scale greenhouse production.

    The second problem this project will address is the non-existence of local fruit during the winter months. Conventional High Tunnel production has only been able to extend the growing season by a month after the first fall frost and a month before the last spring frost. Late fall and winter holidays traditionally focus on fruit side dishes and desserts, yet fresh ingredients for these dishes must be imported from other regions and countries. Trends driven to support sustainable and environmentally conscious growing practices makes conventionally fueled greenhouses unappealing to a growing number of consumers. Local winter fruit production in an ECSG would fill this existing demand while reducing the carbon footprint through sustainable production and shorter delivery distance. The National Restaurant Association's Top 20 Trends for 2010 included five list items that referred to sustainability or local or farm/estate branded items. These trends will most likely carry forward in the coming years. Winter fruit production in an ECSG would adhere to both the principles of sustainability and locally sourced. Direct marketing to area restaurants could allow for the product to be farm branded. Fresh holiday fruit would also garner a premium price, thus stimulating the incomes of local producers.

    Records will be kept to track yield, cost and returns, and cash flow. These records will be used to determine the profitability of the crop. Daily weather and interior temperature readings will be recorded. This information, along with a project summary, cost and returns data, and the trial conclusions, will be published in an informational pamphlet to be distributed to other producers.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.