In 2002, Carandale Farm initiated an on-farm trial for screening unknown, little known and overlooked fruit crops for adaptability, sustainability and economic potential.

Goals of the project included:
• introduce new choices in the local food shed
• strengthen producer-consumer relationships
• diversify the agricultural base (especially in urbanizing areas)
• create profitable niche markets
• benefit public health by introducing more fresh and processed fruit products

Economic sustainability is necessary for commercial fruit growers, but social and environmental sustainability cannot be overlooked in a changing world. Climate change due to global warming associated with burning fossil fuels will demand unprecedented energy conservation in addition to an emphasis on renewable energy sources that are carbon neutral.

In an arguably over-populated world, the need for a nutritionally balanced and sustainable food system will become paramount. Perennial fruiting systems are energy efficient and nutritionally balanced. Diversity takes advantage of symbiotic relationships that reduce pest problems and maximize soil nutrient availability and efficiency. A series of fruiting plants that ripen sequentially and can be similarly mechanically harvested and processed can compensate for the “economics of scale” attributed to mono-cultural systems that are less sustainable.

On the 10th anniversary of the Carandale fruit trials, the site was started to offer observations and anecdotal interpretations. This is not a replicated trial (with the exception of the plum trials), nor are the observations peer-reviewed or statistically evaluated. Research is a snapshot in time and location. Additional information from amateur and professional sources will further the cause of encouraging and implementing sustainable systems using uncommon fruits.

This site has been designed and is hosed by the UW-Madison Center for Integrated Agricultural Systems (CIAS). The research project was funded by Agricultural Development and Diversification (ADD) grants from the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) . This is not intended to be a one time, stand-alone site, but rather to be dynamic, interactive and ongoing. Additional input is welcomed.

Research background

In 2002, grant funds were used to purchase plants and establish a two-acre plot, later expanded to three acres. The research goal was to identify nutritionally rich food types that could be grown successfully (and profitably) in a permaculture environment, taking advantage of symbiotic relationships. The goal was to identify adaptable as well as environmentally, socially, and economically sustainable fruit types for a local/regional distribution and marketing system that would contribute to local economies, resulting in an equitable distribution of wealth and job opportunities while reducing the carbon footprint of the food system.

The first 335 perennial, deciduous fruiting plants were planted in the spring of 2003. Subsequent grant funds helped finance a drip irrigation system, a weather monitoring station and additional plant trials. 54 distinct fruit types and 140 cultivar variations were evaluated. Even those that have been eliminated from further consideration will be discussed. Carandale continues to add more fruit types as they become available and/or have been suggested for addition.

Carandale Farm also intends this to be a replicable model for evaluating fruit types in other climate zones.

Research parameters

Plant selection
• Perennial, edible fruit-bearing plants
• Cold hardiness Zones 2-5 (mostly 3 and 4) with minimal winter hardiness of -20 degrees F
• Soil pH range 5.5-7.5 (generally 6.0-7.0)
• No plant size restrictions, but mostly bushes and shrubs with mechanical harvesting potential

Plant screening
• Horticultural adaptability
• Invasive potential
• Pest issues
• Fruitfulness
• Fruit quality

Plant objectives
• Low maintenance
• Consistent performance
• Non-invasive
• High productivity
• Hardiness
• Processing versatility
• High nutritional value

Other guidelines
• Native species given priority
• Considered all temperate climate species from around the world
• Avoided known invasive species
Screening is being done to maximize nutraceutical and nutritional benefits.

Test site background

The test plot is located just south of Madison near Oregon, Wisconsin. The winter hardiness zone classification at this site is between Zones 4 and 5 (4b). The lowest temperature recorded at the site since the weather station was installed in 2004 was -31,6 degrees F (January 16, 2009). Average minimum temperature during the last eight years has been somewhat warmer than -20 degrees F.

Soils at the site are classified as silt loam, but are extremely variable due to their glacial origin and heterogenous deposition at the southern most fringe (terminal advance) of the last glacial period, about 12,000 years ago. The soil is classified as Westville silt loam, but may also include some Pecatonica and Troxel silt loams. Internal soil drainage is only moderate as is reflected by the poor adaptability of plant species such as Hardy Kiwi that demand good internal soil drainage.

Organic matter is about 2 percent, but improvements are being made with compost and organic mulches. The site has a 3 percent slope, providing good surface water drainage. It has an easterly exposure that delays bloom and reduces frost and freeze injury.

The site has a long and variable cropping history. The last crop was strawberries in their last year of a four-year fruiting cycle. It is bordered on the west by a mature pine windbreak. The windbreak reduces desiccation in the dormant period and wind stress in the growing season.
The downside of the windbreak is that it increases leaf drying time that can increase disease pressure. Shade from the windbreak can also reduce fruit production. These undesirable features actually become beneficial in the test plot because it provides more information about tolerance for disease pressure and shading.

Test site layout, preparation and maintenance

The site was tilled after strawberry harvest in July 2002, and kept weed-free until planted to a permanent grass cover in the fall. In early spring of 2003, a spading machine was used to establish 5-foot wide planting strips, through a weed-free sod cover, spaced 22 feet apart center-to-center. An in-row planting grid at four-foot intervals was marked with flags.

The trees, bushes, shrubs and vines selected for evaluation would vary greatly in size and root structure upon maturity. The plants were spaced in multiples of the 4-foot grid (4,8,12 or 16 feet, etc.), based on recommendations for each plant type. Row orientation is north and south. Cultivation, leaf mulch and hand weeding were used to control in-row weeds. The sod cover between rows was maintained by mowing.

Maintenance has varied over the years based on the competitiveness and needs of individual plant types. As the planting matured, growers used mulches and sting trimming replaced mechanical tillage for weed control. Trees and other plants vulnerable to rodent girdling are protected by hardware cloth barriers, preferred over plastic tree guard that can promote disease and insect damage is not constantly monitored and maintained. The greatest maintenance challenge is control of Canadian Thistle and Field Bindweed, which are especially problematic in the Ribes subplot and other shrubs and bushes that generate new canes annually.

The site was protected from deer by a temporary electric fence around the perimeter until a permanent seven-foot deer fence was erected in October 2003. An overhead irrigation system was installed at planting time to supplement rainfall as needed. Knowing that overhead irrigation would not be adequate as larger shrubs and trees matured, drip lines with emitters were installed in 2004 to supplement and eventually replace the overhead system

The research plot is divided into three areas.
• The primary area contains perennial fruiting plants that are unknown, little known or under used as food crops (though some have been promoted for landscape and/or wildlife food plantings).
• The second area is devoted to Ribes, that are being screened to determine what selections are best adapted with the most marketing potential in the U.S. (Currants and gooseberries are popular in Europe and are being re-introduced in the U.S. as a diverse and healthful dietary component.)
• The third area is devoted to variety trials for regional adaptability and marketability of stone fruits, primarily plums and cherries. Adapted varieties could have a major role as a fresh fruit in regional marketing systems where freshness, quality and flavor are a value-added feature.
Before the plants start fruiting, no pesticides or commercial fertilizers are used. The intent is to evaluate environmental adaptability using only sustainable practices. After fruiting starts, the emphasis changes to fruitfulness and fruit quality. At that time some pesticides are selectively used if needed.