Evaluation of hardy fig varieties in a northern New England high tunnel

Final Report for FNE14-797

Project Type: Farmer
Funds awarded in 2014: $14,992.00
Projected End Date: 12/31/2017
Region: Northeast
State: Maine
Project Leader:
Bill Errickson
Singing Nettle Farm
Expand All

Project Information

Summary:

This research explores the potential for organic fig (Ficus carica) fruit production in a northern New England high tunnel (Zone 5b). The study was conducted over the course of two growing seasons (2014-2015) and included on-farm and off-site outreach in 2015. Building on the success of fig producers who have utilized high tunnels in the mid-Atlantic states and on variety trials of fig enthusiasts in New England, this project is the first to quantify the survivability, productivity, and economics of four hardy fig cultivars (Gino’s Black, Marsailles Black VS, Ronde de Bordeaux, and Sal’s GS) grown in a high tunnel in coastal Maine. Half of the trees of each variety also received additional winter protection in the form of an Agri-bon row-cover wrap. While all trees exhibited complete above-ground winter dieback, nearly all varieties did survive and regrow from the roots the following spring, with the exception of the uncovered GB trees, in which only 50% survived. Covered RDB trees displayed the greatest vegetative growth (1200 inches of total stem length in 2015). Uncovered RDB trees had the highest average fruit set (70 fruits per plant) followed closely by MVBS (69 fruits per plant). Ripe fruit harvested from MBVS had the highest average Brix values (19.0) and scored highest overall on the taste-test. While the results are encouraging and suggest that figs have potential as a high tunnel crop in the Northeast, future investigations into methods to increase above-ground winter survivability, including heavier winter covers, laying trees down and mulching, and/or supplemental heat sources are needed before recommending fig production as an economically viable commercial endeavor in this climate. Outreach from this project included a workshop at the MOFGA Common Ground Education Center with over 75 participants, an on-farm field day that hosted 20 attendees, and an article published in the MOFGA quarterly newsletter.

While the results are encouraging and suggest that figs have potential as a high tunnel crop in the Northeast, future investigations into methods to increase above-ground winter survivability, including heavier winter covers, laying trees down and mulching, and/or supplemental heat sources are needed before recommending fig production as an economically viable commercial endeavor in this climate. Outreach from this project included a workshop at the MOFGA Common Ground Education Center with over 75 participants, an on-farm field day that hosted 20 attendees, and an article published in the MOFGA quarterly newsletter.

Introduction:

In the Northeast, where farmers consistently struggle with climatic challenges presented by a short growing season, cool temperatures, and harsh, unpredictable winters, agricultural producers are often dedicated to increasing the diversity of their enterprises, building sustainable farms that provide a livelihood and comprise the local food system. When considering a farm system’s resilience and the security of a local or regional food system, fruit production is an area of particular interest. There is currently a high consumer demand for local fruits in the Northeast, though the production of many traditional species presents ecological and financial challenges. Apples and plums, for example, frequently suffer from insect and disease pressure and are subject to crop failure when pollination is disrupted due to cold spring temperatures and rain during bloom times. The pesticides necessary to produce a marketable fruit crop pose both environmental risks and a health danger to farmers and consumers. As pest, disease, and moisture issues increasingly plague the traditional fruits of the Northeast, farmers must begin to consider alternative approaches for fruit production, including the incorporation of additional species into our agricultural systems.

 

Figs, native to the Middle East and Western Asia are one of the earliest cultivated plants in the world, with origins that go back over 11,000 years. Exceptionally high in calcium, the fruits are produced on self-fertile trees with minimal pest and disease issues. They can be enjoyed fresh, and also dry well for winter storage, having the potential to provide income for the farmer and local fruit for consumers beyond the window of harvest. Figs are currently shipped great distances to consumers in Maine; however, they have the potential to be produced in this region if given adequate microclimate conditions. While annual crops such as tomatoes and overwintered greens, and occasional specialty crops such as ginger, are currently produced in high tunnel growing spaces, perennial crops offer the prospect of reduced soil disturbance and therefore less nutrient, moisture, and organic matter loss during production. Expanding the use of high tunnel structures to include perennial crops such as figs opens a new window of sustainable agriculture opportunity in the Northeast while decreasing the region’s dependency on fossil fuels for the production and import of fruit. The major challenges of producing a fig crop in the Northeast lie in the success of overwintering the plants and ripening the fruit.

 

While some home gardeners have been experimenting with growing figs in the northeastern United States in recent years, there is a significant lack of scientific field trials to date. Variety trials in such countries as Egypt(1) and Turkey(2), and in the state of Hawaii(3), have evaluated multiple fig varieties for productivity; however, these studies have not evaluated the productivity of cold-hardy figs specifically, nor pressed the climatic limits of the species. Previous SARE-funded research in New Jersey demonstrated that figs are a viable high tunnel crop, producing higher yields of marketable fruit and exhibiting higher rates of winter survival when compared to field-grown figs(4). Additional research has demonstrated the viability of perennial fruit crops such as strawberries(5,7), blackberries(6), and raspberries(7) in high tunnel production systems. Ginger, which thrives in a tropical environment, has been shown to be a viable northeast hoop house crop(8).

 

This research built upon the New Jersey fig study by applying their successful findings (using appropriate high tunnel technology) to further test the climate boundaries of the fig tree and assess whether a marketable, and economically viable, crop can in fact be produced in a northern New England state. The fig varieties selected for this study are suggested to be hardy, when planted unprotected, to approximately -15 0F (Zone 5). Brooks, Maine is currently rated as Zone 5b. High tunnels, which are generally understood to moderate the extreme temperature fluctuations during the coldest winter months, are also expected to raise temperatures inside the tunnel anywhere from approximately 7 to 12 0F9.

This trial was conducted by Bill and Lauren Errickson of Singing Nettle Farm in conjunction with Mark Fulford of Teltane Farm. While Singing Nettle Farm commenced its operations at the conclusion of the 2015 growing season, the farm was a certified organic, horse-powered, off-grid operation, specializing in vegetables, fruits, medicinal herbs, and nursery stock during its six years of operation. The farm consisted of approximately three acres of annual and perennial crops, ten acres of pasture, and additional forested land. All fieldwork and sustainable forestry practices were conducted with a team of Haflinger horses. Singing Nettle Farm marketed their produce and cut flowers through a 40-member CSA, the Common Ground Fair, the Brooks Farmers’ Market, a local restaurant, and the RSU-3 school district. Nursery stock is sold through the Fedco Trees mail-order catalog and direct retail sales. Figs were a natural fit within the diverse, developing perennial agroecosystem of Singing Nettle Farm. While the Erricksons are no longer owner/operators of the farm business, the land base and all of the plantings are now being managed by the next generation of organic farmers to steward that property. Mark Fulford, technical consultant, has over 35 years of experience growing and trialing fruit crops at his diversified farm in Monroe, Maine. Mark specifically aided as a consultant regarding soil and plant health throughout the duration of this study.

1Abo-El-Ez, A., Mostafa, R., and Badawny, I. “Growth and productivity of three fig (Ficus carica) cultivars grown under upper Egypt conditions.” Australian Journal of Basic & Applied Sciences, Feb2013, Vol. 7 Issue 2, p709-714.

2Caliskan, O. and Polat, A. “Morphological diversity among fig (Ficus carica) accessions sampled from the Eastern Mediterranean region of Turkey.” Turkish Journal of Agriculture & Forestry, Apr2012, Vol. 36 Issue 2, p179-193.

3Love, K. 2007. “Choosing the best figs for Hawaii.” SARE project number FW07-034.

4Sheets, M. 2011. “Raising fig trees in high tunnels in the northeast.” SARE project number FNE11-727.

5Coldwell, D. and Wells, O. 1997. High tunnel strawberries for New England.” SARE project number FNE97-164.

6Gundacker, E. 2009. Growing blackberries organically under high tunnels for winter protection and increased production.” SARE project number FNC09-749.

7Mielke, D. 2002. The use of moveable high tunnels in the organic production of strawberries, potatoes, and raspberries.” SARE project number FNC02-387.

8Bahret, M. 2007. Greenhouse ginger cultivation in the Northeast, Part II.” SARE project number FNE07-596.

9Rutgers New Jersey Agricultural Experiment Station. High Tunnels in New Jersey.” <http://njsustainingfarms.rutgers.edu/hightunnels.html> Accessed 2013 Nov 22.

Project Objectives:

The objectives of this study were to:

1) Compare the survivability and productivity of four of the hardiest available fig varieties in a northeast high tunnel

2) Determine the usefulness of providing additional winter protection by wrapping fig trees with row cover

3) Assess the economic viability of figs as a northern New England fruit crop.

The objective of this research was to identify one or more varieties of fig tree that can be successfully grown to produce marketable fruit in USDA Zone 5b with the protection of a high tunnel. In addition to showing varietal differences, the results suggest how variation in winter protection practices influences fruit production and survivability. To make these determinations, winter hardiness, bloom time, harvest dates, total stem length, total and marketable fruit yield, Brix levels, and taste were measured. A complete crop budget was created to account for financial expenses, labor inputs, and projected profit from fruit sales.

Cooperators

Click linked name(s) to expand
  • Lauren Errickson
  • Mark Fulford

Research

Materials and methods:

In the spring of 2014, four varieties of fig trees hardy to zone 5 (Gino’s Black, Marsailles Black VS (MBVS), Ronde de Bordeaux (RDB), and Sal’s GS) were planted in a 26×48 foot high tunnel in mid-coast Maine, Zone 5b. Eight trees of each variety (a total of 32 trees) were planted on five foot centers into soil that had been amended for optimum fig tree nutrition with a mineral and worm castings blend, which included granite meal, colloidal phosphate, bone char, and kelp meal, based on a soil test taken prior to planting. All trees were mulched with wood chips and landscape fabric and watered with drip irrigation at regular intervals throughout the growing season. In the fall of 2014, four trees (half the total number) of each variety were wrapped with fabric row cover for the winter to assess whether there is a benefit to providing extra protection from freezing temperatures.

In 2014 and 2015, data was collected for the following parameters: flowering dates, harvest dates, total yield of fruits, yield of marketable fruits, yield of unripe fruits, fruit size (average weight per fruit), total stem growth, peak plant height, Brix levels, taste, and economics. Winter survival data was collected in the spring of 2015 by measuring the percentage of winter injury/die back on each tree. The effects of wrapping trees in the winter are quantified by comparing wrapped vs. un-wrapped trees on the basis of the above parameters.

Trees were monitored daily during their potential bloom period to ensure accurate data collection. Figs produce an inflorescence, called a syconium, which contains numerous unisexual flowers that are not outwardly visible; thus, flowering dates were recorded as the first observance of syconium formation. Harvest dates were recorded for each variety, wrapped and unwrapped when ripe fruits were harvested. Total yield of ripe fruits was calculated by weighing the fruits of each harvest throughout the season, for each variety, wrapped and unwrapped. Average fruit size was calculated by counting the number of fruits in each harvest and dividing the total weight by the number of fruits for each variety, wrapped and unwrapped trees. Total fruit set was also evaluated by counting all fruits on the plants, whether they ripened or not. This data was used in the budget projection as an estimation of yield potential if all fruit were to ripen.

Winter survival rate was determined first by total tree mortality or survival for each variety, wrapped and unwrapped. Second, for surviving trees, overwintering rate was determined by measuring the length of vegetative die-back on each tree and obtaining an average for each variety, wrapped and unwrapped. Dead wood was pruned each spring.

Vegetative growth was measured in September, after all growth for the season had culminated. Measurements were taken from each tree, with average values calculated for each variety, wrapped and unwrapped. Because the figs in the high tunnel were grown as multi-stemmed plants, and each stem has the capacity to produce fruit, the length of every stem was measured and recorded.

Brix levels were measured using a refractometer; sap from three fruits from each tree were measured at peak harvest for that variety. Average Brix readings were calculated for each variety, wrapped and unwrapped trees. Taste was evaluated by conducting an on-farm, blind taste test of each variety from wrapped and unwrapped trees. Participants were recruited from the community and each received a comment card to numerically score each sample according to defined taste parameters, including sweetness, aroma, and texture. Participants were asked to evaluate each parameter on a scale of 1 to 5, and to provide additional written comments for each variety.

An economic analysis was performed by creating a crop budget for each variety, wrapped and unwrapped trees. Labor, infrastructure, amendments, and the cost of trees were included as expenses; potential sales of marketable fruit were projected.

The 2014 season essentially served as an establishment year for the trees, while data gathered in 2015 provided more accurate results. While this study was originally planned to continue through the 2016 growing season, the trial concluded in 2015 because Singing Nettle Farm ceased all operations and was sold at the end of the year.

Research results and discussion:

The winter of 2014-2015 saw temperatures of -15 degrees F, and resulted in all the fig trees dying back to the ground, regardless of whether they were wrapped for additional winter protection or not. In the spring, all tress began growing again from the base, with the single exception of the uncovered GB trees, which experienced complete winter mortality in two out of four plants.

Figs produce an inflorescence, called a syconium, which contains numerous unisexual flowers that are not outwardly visible; thus, flowering dates were recorded as the first observance of syconium formation. In 2015, the first syconiums were observed on SGS on June 19th, followed by MBVS on June 26th, and RDB and GB on July 3rd.

Vegetative growth was calculated for each variety by measuring stem length for covered and uncovered trees (Figure 1). Covered RDB plants displayed the greatest amount of vegetative growth of the four varieties, averaging 1200 inches of total stem length per plant, while uncovered RDB had slightly greater than 1,000 inches of stem length per plant. Covered GB and covered MBVS demonstrated the next highest levels of stem length, with 620 inches and 580 inches respectively. Vegetative growth was greater in covered varieties of GB, MBVS, and RDB, while winter protection did not result in greater vegetative growth for SGS.

Figure-1-Vegetative-Growth-and-Figure-2-Fruit-Set

Fruit set for each variety is displayed in Figure 2 and is described here in order of productivity. Uncovered RDB and covered MBVS had the highest fruit set, producing 70 and 69 fruits per plant, respectively. Covered GB plants produced an average of 61 fruits per plant and covered RDB averaged 58 fruits per plant. Uncovered SGS produced an average of 49 fruits per plant, while uncovered MBVS averaged 43, and covered SGS averaged 38 fruits set per plant. Uncovered GB only set an average of 6 fruits per plant.

For covered trees, each variety did successfully produce ripe fruits, which were weighed, and evaluated for Brix levels. The first ripe fruit was produced by SGS with winter protection on September 19th. The harvest continued until the first week in November. All ripe fruit harvested was considered marketable. From the covered GB trees, 3 ripe fruits were harvested, with an average of 0.75 fruits per tree, an average weight of 0.33 oz, and an average Brix of 16. Covered MBVS trees yielded 17 fruits, with an average of 4.25 fruits per tree, an average weight of 0.57, and an average Brix of 19. Covered RDB trees produced 12 ripe fruits, with an average of 3 ripe fruits per tree, an average weight of 0.56 oz, and an average Brix of 16.5. Covered SGS trees were the first to bear, and produced 23 ripe fruits, with an average of 5.75 ripe fruits per tree, an average weight of 0.52 oz, and an average Brix of 17.7. RDB was the only variety to ripen fruit on trees that were not covered through the winter, yielding 2 fruits, with an average of 0.5 ripe fruits per tree, an average weight of 0.55oz and an average Brix of 16 (Table 1).

Table-1-Ripe-Figs-Harvested

Independent blind taste tests were also conducted for each variety in 2015. Taste test participants were given one variety at a time, with a scorecard to rank the qualities of each variety ranging from one to five for texture, sweetness, floral/aromatic, and overall flavor, with five being the highest score. An open ended “comments” section was also included on the cards for additional feedback. Participants were unaware of which variety they were sampling during each phase of the taste test. MBVS scored highest overall, followed by SGS, GB, and RDB. Descriptive comments during the taste test suggest banana flavors for GB; sweet melon flavors for MBVS, a subtle spicy sweetness for RDB, and a very good, complex flavor for SGS. It is also worth noting that the RDB figs may not have ripened to their full potential, affecting their scores in the taste test (Table 2).

Table-2-Fig-Taste-Test

An enterprise budget was created to illustrate the expenses and potential income for producing figs in a high tunnel in Maine (Table 3). While there will likely be no income realized in the first year, an income projection was made based on the fruit that was set during the second year, provided the grower could get all of the fruit to successfully ripen with additional winter protection and/or supplemental heat. Production would likely increase for the third and fourth years. The budget was based on 32 plants occupying 2/3 of a 26’x48’ high tunnel, with a projected project lifespan of 20 years. Expenses included the plants, the physical high tunnel structure, plastic covering for the tunnel, drip irrigation infrastructure, annual irrigation events, soil amendments, landscape fabric, winter coverings, and labor. The annual expense for growing and maintaining 32 trees is estimated at $841.70 or $26.30 per tree. Income was estimated using an average of 60 fruits set per plant, weighing 0.5 oz each; an average of 1.875 lbs per plant. If 60 fruits were ripened on 32 trees, a total yield of approximately 60 lbs could be expected. In order to break even, the producer would need to charge $14/lb for figs. If productivity were to increase in future seasons, additional income could be realized. However, this study did not achieve those production goals in the second year, and additional work on winter survivability and increasing the percentage of ripe fruit will be essential before figs can become commercially viable. 

Table-3-Fig-Enterprise-Budget

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

In 2015, Singing Nettle Farm hosted an on-farm field day in which 20 participants visited the farm to observe the figs growing in the high tunnel and to learn about the research underway. Each participant received a handout summarizing the variety trials. Attendees were able to tour the high tunnel, ask questions, and even sample ripe figs on this day.

2015-Handout

Flyer

The outreach component of this study also extended to the MOFGA Common Ground Fair, where Errickson delivered a presentation to 75 participants. Attendees received handouts summarizing the study, while viewing a slideshow summarizing the research. A question and answer session followed the presentation, and participants were invited to continue the conversation at the Singing Nettle Farm booth in the Farmers Market.

Fig-Presentation

In 2016, an article was written and published in the Maine Organic Farmer and Gardener and this project was used as a case study for experimental design in crop variety trials in a course that Errickson taught at Stockton University. The Erricksons also presented their work on Singing Nettle Farm at the NOFA-NJ winter conference in January 2017, which included a discussion of this study.

Figs-MOFGA-Article

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Future Recommendations

Our initial findings regarding hardy fig production in an unheated high tunnel in Maine suggest that, while it is possible to successfully ripen fruit, yields would improve with additional winter protection. While the majority of our trees regrew from the base after dying back in the frigid winter of 2014-2015, this level of winter injury most likely set them back in terms of earliness and overall amount of fruit that was able to ripen. If growers can maintain a greater degree of above ground winter survivability, the plants will have a better start, and potentially produce a better crop the following year. One way to achieve this is to lay the trees down in the fall by cutting the roots on one side with a spade, and covering them with a heavy layer of mulch. In the spring, the trees can be stood up again, though they may need additional support on the side with the severed roots. Heavier winter covers on the plants or a minimal amount of supplemental heat may also be an option for growers who have that capability. Additional crops, such as winter greens, may simultaneously be grown in a heated winter greenhouse with the dormant fig trees, in order to maximize the use of the space, further justifying the extra expense and energy use of the supplemental heat. In the summer, additional crops such as melons, cucumbers may be grown as an understory companion to the figs that will become the greenhouse canopy. Figs are also fairly easy to propagate from cuttings in the spring. This can provide both an additional source of plants for home use and/or another source of income from the sale of plants. In addition to the four figs trialed at Singing Nettle Farm, Brown Turkey and Hardy Chicago may also bring success if growers can be sure to have sourced a true strain.

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.