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

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

Summary

This research is exploring the potential for organic fig (Ficus carica) fruit production in a northern New England high tunnel (Zone 5b). 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 grown in a high tunnel in coastal Maine. The study is taking place over the course of three growing seasons (2014-2016) and will include on-farm and off-site outreach in 2015 and 2016.

In 2014, Bill Errickson (owner) and Mark Fulford (technical advisor) amended the soil in the high tunnel and planted eight figs each of the four varieties (Gino’s Black, Marsailles Black VS, Ronde de Bordeaux, and Sal’s GS) for a total of 32 plants. Wood chip mulch and landscape fabric were applied after planting and water was supplied throughout the season using drip irrigation. Data on plant height and fruit yield were collected during 2014. After leaf drop, four trees of each cultivar were wrapped with fabric row cover to evaluate the necessity of additional winter protection. The row covers will be removed in the spring of 2015, at which time winter dieback will be measured.

Objectives/Performance Targets

The objective of this research is 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 will demonstrate how variation in winter protection practices influences fruit production and survivability.

In the spring of 2014, four varieties of the hardiest available fig trees (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, including 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 were 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, 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), peak plant height, Brix levels, taste, and economics. Winter survival data will be collected in the spring of 2015 and 2016 by measuring the percentage of winter injury/die back on each tree. The effects of wrapping trees in the winter will be quantified by comparing wrapped vs. un-wrapped trees on the basis of the above parameters.

Accomplishments/Milestones

Initial baseline data was collected during the 2014 season as figs trees were establishing in the high tunnel. The fig trees were transplanted from 5 inch pots in May and all varieties were flowering by the middle of July. 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. Plant height was measured in October, after the cessation of vegetative growth for the season, with some trees reaching 72″ in this first year. Average plant heights were recorded as follows: Gino’s Black: 52″; MBVS: 55″; RDB: 56″; Sal’s GS: 36″. Each variety, with the exception of RDB, had some individual plants that suffered transplant shock when transitioning to the conditions of the high tunnel, setting their growth back during this year of establishment. Two ripe figs were harvested from a RDB plant in September and 1 ripe fig was harvested from anMBVS plant in November. The fruit of the RDB had an average weight of 0.04 lbs and a Brix level of 17. The fruit of the MBVS weighed 0.03 lbs and had a Brix level of 19. In November, unripe figs were counted and removed from the trees. The average number of unripe figs per tree was recorded for each variety as follows: Gino’s Black: 7; MBVS: 7; RDB: 17; Sal’s: 9. The 2015 and 2016 seasons will also include comparative data for wrapped vs unwrapped plants of each variety, to determine the efficacy of additional winter protection. Labor hours and costs are being documented during the establishment year to develop a comprehensive crop budget following the third season. Taste analyses will be performed in 2015 and 2016 when specimens of each variety are ripe for comparison. Data will be collected regarding winter injury/dieback in 2015 and 2016 to evaluate the cold hardiness of each variety when overwintered in the high tunnel.

Impacts and Contributions/Outcomes

Collaborators: