Techniques for Growing and Overwintering Japanese Fig Tree Espalier in the Northeast

Progress report for FNE22-003

Project Type: Farmer
Funds awarded in 2022: $30,000.00
Projected End Date: 11/30/2024
Grant Recipient: Boyer Holdings LLC
Region: Northeast
State: Pennsylvania
Project Leader:
Craig Boyer
Boyer Holdings LLC
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Project Information

Project Objectives:

This project will contribute to an understanding of whether figs are a viable fruiting crop for retail and wholesale markets for distribution in the NE.  The main objectives of the project are: 

Primary

(1) Establish a fig orchard with low-cordon espalier using the Japanese Stepover method and (2) replicate the results of previous efforts in this area with improvements to determine if the above method is viable and scalable for fruit production.

Secondary

(1) Utilize high tunnels to extend the seasons on each end--both spring and fall and (2) use low tunnels with light mulching to further create a microclimate for cordons to survive the winter and consistently produce a fig crop.

My hope is to get one step closer to inaugurating a wave of northeastern commercial fig orchards, bringing this ancient and elusive fruit to our climate so that it can be shared and treasured regardless of socioeconomic status. If successful with figs, other Mediterranean fruits may also be grown similarly on a commercial scale. If we can redefine local as meaning within 50 miles--not 500 miles--I believe we can make the lives of both farmers and consumers more gratifying. 

Establishment of Fig Cordons from base of the plant. Picture of Fig Epslier before Cordons are pruned to encourage vertical growth.

 

Introduction:

Figs were one of the very first cultivated fruit trees (1).  The tree and its fruit (or flower, rather) have inspired stories and cultures in both ancient and modern times.  Although figs have been successfully cultivated in the Northeast for many years in backyards both in-ground and pots, no commercial fig growing operations exist north of the Mason-Dixon line.  In fact, California produces 98% of the country's fresh and processed fig fruit (2). How do we build upon the success of backyard fig enthusiasts, who are indeed harvesting fig fruit consistently from pots and in-ground trees throughout the Northeast, and scale that into a commercial operation in which figs are produced, marketed, and sold locally? 

I’d like to apply new growing and overwintering techniques to Mediterranean fruit crops, starting with the fig, using high tunnels.  If we can learn to produce high-value crops like figs, which are typically grown on the West Coast and shipped across the continent, this will help reduce our carbon footprint.  This will also provide more people an opportunity to taste a locally produced, fresh fig versus one that is necessarily harvested early for extended transport. This is at odds with the fig's ephemeral quality; when picked and eaten at its peak of ripeness, it is beloved, and has inspired thousands of backyard growers.

Whereas some have reported success in growing figs and other unique crops like citrus throughout the tri-state area, the larger commercial market is unexplored.  The barriers to entry in growing Mediterranean crops are high, and the accessibility of information to enter the market is scarce.  If we can develop a more sustainable way to overwinter fig trees in zones 6 and 7, we can bring local fig fruit to retail and wholesale markets in the tri-state area, while minimizing fossil fuel expenditures. This in turn will produce more local jobs and grow the market share directly for figs and other Mediterranean-originated fruit grown and sold in the Northeast.   

Historically, the heating high tunnels used for growing figs has been inefficient. The entire tunnel is typically heated, using natural gas, propane, or fuel oil.  This method wastes both energy and space. Fig trees are unique, in that the fruit forms on new growth, not old growth. I propose using the Japanese Stepover Espalier technique (3), Using this method, permanent cordons are established slightly above or at ground level (at ground level, they can be mulched for an extra layer of protection).  Once the cordons are established, fruiting branches can be formed every 14 inches along the horizontal growth.  These vertical branches are then pruned back every year and new buds emerge the following year, forming new vertical branches on which fruit will form.   

To overwinter these cordons, I used Eliot Coleman’s system (4) of floating row covers over the cordons inside the high tunnel. Coleman has used this method for years to grow cold-hardy crops without heat in Maine. According to Coleman, "Double coverage moves the covered area about three USDA zones to the 'south' "(5). During extremely cold nights or weeks, greenhouse plastic could also be added directly on top of this floating row cover. This method allows the soil to store the heat. Coleman commented, “When the outdoor temperature drops to –15˚F (–26˚C), the temperature under the inner layer of the cold house drops only to 15˚F  to 18°F above zero (–10˚C to –8°C) on average (5).” Cold-hardy fig trees will suffer no die back until the temperatures are consistently lower than 15˚F. An alternative source of income could be produced while the trees are dormant by planting cold-hardy crops under these row covers.

\Temperature sensor placed on outside of tunnel on ground, inside of tunnel on ground, and at the top of the floating row cover to track temperature. Floating row covered placed over fig espalier in mid December.

Description of farm operation:

I have grown fig trees for retail sales since 2017. More recently, I have entered the wholesale fig tree market. When I learned that California and Florida were the leading producers of fruit and plants, I decided to make it my mission to bring this specialty crop directly to and from the NE market. Currently, I farm part time on 2 acres My wife and I have 8, soon to be 9 children. My oldest children are involved in small tasks like moving plants, placing soil in pots, and planting figs. My high tunnel covers 5,000 square feet. Last year, my tree sales (including other items like citrus, raspberries, blackberries, pomegranates, guavas, olives, etc. was $28,000.

Cooperators

Click linked name(s) to expand/collapse or show everyone's info
  • Bill Lauris - Technical Advisor (Educator)

Research

Materials and methods:

The first step in the process of establishing a Japanese Stepover Espalier was to plant fig trees in the high tunnel. Fig cuttings were started in cells during the winter of 2021 and 2022; the trees were about 1 foot tall when transplanted from their cells. They were planted in May of 2022.  At the time of planting, the apical bud was pinched to induce branching. From this branching, two leaders were chosen as the cordons.  A piece of wire was run 1 inch from the ground over the length of the row, and tomato clips attached the cordon to the wire.  

The selected branches were allowed to grow 2 1/2 feet vertically.  Once this growth was established, the lower 6 inches was clipped to the guide wire. This allowed the apical bud to continue growing vertically (which is more vigorous than horizontal growth), while slowly training the cordon along the wire.  The bottom was trained horizontally biweekly or whenever the horizontal growth was above 2 1/2 feet, encouraging cordon formation horizontally. Leaves were trimmed from the cordon as it was attached to the wire. During this period, the trees were fed fish emulsion, a high nitrogen fertilizer via micro sprinklers.

Vole Traps have been successful so far in capturing both voles and mice in the high tunnel.
Vole Traps in Action

The primary goal in 2022 was to establish healthy cordons and to gain optimal thickness. Thicker, more lignified fig wood survives lower temperatures better than thinner, non-lignified wood (1). To accomplish this, all suckers and fruit were pruned in the first year until the desired length of the cordon was reached. Trees were spaced 7 feet apart in each row, with 6 feet between rows, allowing for 120 trees in our 5000 square foot high tunnel. 

 Eliot Coleman-style vole traps (non-baited mouse traps set inside of wooden boxes with small entrance holes) were placed inside and outside the high tunnel in mid-December 2022(2).  Voles can do serious damage to a fruit orchard by girdling the bark and eating through the base of the plant. Vole traps were checked and reset daily through the winter months.  These traps alone proved to be enough in deterring voles from entering the high tunnel. 

Beginning in November of 2022, a wireless thermometer and humidity gauge were placed on the ground in the high tunnel. Once nightly high-tunnel temperatures begin to dip into the mid-20s for more than an hour or two a night (in 2022 this was mid-December), the low tunnels were deployed.  64# pre-arched wire hoops were placed over the cordon row and Dewitt AG19 was placed over these wire hoops. A second temperature sensor was placed on the ground next to the cordon and a third sensor was placed at the top of the arch inside of the low tunnel. Temperature and humidity from these thermometers were taken and recorded every minute. 

A support system for the vertical espalier growth was erected in early 2023.  Wires were run above the trusses and connected to the end walls.  Two wires were run for each cordon about 4 feet apart.  S hooks were attached to the support system.  Tomahooks (Tomahooks | Lower & Lean | Johnny's Selected Seeds (johnnyseeds.com) were wrapped with string and used to establish the vertical fruiting branches from the cordon.  Starting in spring of 2023, buds were allowed to form on the cordon every 14 inches. All other buds were removed at first sight. As buds formed into branches, the branches were trained out from the cordon to allow light and air to reach the center of the cordon. 

Strings attached to tomahooks from the rafters of the greenhouse support vertical Espalier growth.
Vertical growth supported by stringreach the center of the cordon.

Suckers were pruned from the vertical fruiting branches.  The branches were trained with Dr. Gowaty figs forming on the Cordon June 12, 2023. tomato clips weekly. Once fruit began to form and, the leaves below the fruit were pruned from the bottom of the plant moving up as the fruit ripened (like pruning low vegetative growth on greenhouse tomatoes to improve airflow). Leaves below harvested fruit were continually pruned to increase airflow. Starting in early May, the trees were fed with Fertrell Gold Special Starter 2-4-2 which was placed at the base trunk under the black woven fabric. 

About 90 days is required for figs to progress from embryo formation to ripening.  The first fruit for the project ripened from the variety Longue D'Aout on August 16th of 2023.   The second variety that ripened was Dr. Gowaty on August 21st.  Ronde de Bordeaux did not start to ripen until September 21st.  Teramo ripened next on September 30th.  Golden Riverside ripened in the beginning of October on the 6th.  Atreano and Susser George ripened right behind Golden Riverside on October 7th.  

Longue D'Aout produced the largest amount of fruit (55 fruits) and was the most consistent.  The others did not produce enough fruit to record.  There was not a sufficient amount of fruit to sell in 2023.  This was disappointing, but my mentor Bill Lauris reminded me that it will take more than one to two years for a significant crop to be produced.  As the trees continue to establish themselves and the cordons continue to thicken this next year, we are excited and anticipate harvesting figs in the middle of July next year as opposed to August.  

Longue D'Aout First Ripe Fruit August 16, 2023 Dr. Gowaty 8/21/2023Ronde de Bordeaux Ripening on Septmber 21st Dr. Gowaty in HandTeramo Unknown Ripening on September 30th.

Golden Riverside Ripening on October 6, 2023Atreano ripening on October 7th Boys with Figs on November 13th

 

 

Espaliered Figs still holding on to their Leaves on October 31stEspaliered Figs losing their leaves on November 20, 2023

The same process will be repeated in 2024. Now that the project is established, I will focus this next year on video documenting every part of the process. 

Research results and discussion:

The temperature monitoring system was set up in early December of 2023.  Five monitoring stations are placed in the following areas:

    1. Monitor 1 has been placed on the ground outside of the High Tunnel
    2. Monitor 2 is connected to the top of the wire hoop inside of the low tunnel. 
    3. Monitor 3 has been placed on the ground inside of the low tunnel. 
    4. Monitor 4 has been placed on the ground, outside of the low tunnel. 
    5. Monitor 5 has been placed on the ground outside of the low tunnel, next to the northern wall of the high tunnel. 

The full results of the temperature monitoring are premature, but so far, the floating row cover has produced significant increases in air and soil temperatures inside of the low tunnel in December 2023.   The low in December on the outside of the high tunnel was 4 degrees Fahrenheit recorded on the evening of December 24th, while the temperature on the soil inside of the low tunnel that evening was 24 degrees Fahrenheit.  The temperature on the ground next to the low tunnel that same evening was 17 degrees. When the temperature outside rose the following day to 29 degrees the temperature on the ground inside the low tunnel went to 62 degrees. 

The highest temperature recorded on top of the soil inside of the low tunnel was 87 degrees on December 30th.  The temperature on the outside of the high tunnel that day was 42 degrees.  For comparison, the highest temperature recorded at the top of the low tunnel was 93 degrees on December 30th when the temperature outside was 42 degrees.  That is a temperature difference of 51 degrees on a sunny day.  None of the fig's cordons were damaged by the low temperatures during the winter of 2022-2023

December Temperature Readings Monitor 1 Outside of High Tunnel Green line is Temperature 

December Temperature Readings Monitor 2- Attached to top wire of Floating Row Cover

December Temperature Readings Monitor 3- On Ground inside of Floating Row Cover

December Temperature Readings Monitor 4- On Ground outside of Low Tunnel

The temperatures in January and February of 2023 were comparably moderate.  The low for outside of the high tunnel in January was 25 degrees F and 15 degrees F for February.  The temperatures inside of the low tunnels did not fall below freezing in the month of January. The temperatures inside of the low tunnels only dipped below freezing one time in the month of February.   Additionally, by mid-February, the temperatures on the ground in the high tunnel, were consistently getting in to the 80s and 90s and even went up to 100 on a few occasions, if the sun was out.  The first recorded bud breaking inside of the high tunnel for 2023 was on March 10th.   Typical bud break inside of a high tunnel without using low tunnels is the second week of April.  This puts fig trees grown as a Japanese espalier under row covers about 4 weeks ahead of those grown only in high tunnels and about 7-8 weeks ahead of those grown in the field. This is a significant movement up in bud break and the main reason that we think we will see ripe fruit in mid-July in 2024. 

January Temperature Readings Monitor 1 Outside of High Tunnel 

January Temperature Readings Monitor 2- Attached to top wire of Floating Row Cover

January Temperature Readings Monitor 3- On Ground inside of Floating Row Cover

January Temperature Readings Monitor 4- On Ground outside of Low Tunnel

As we moved into March and April the temperatures in the greenhouse and particularly under the row cover really began to increase.  After talking with our mentor Bill, we decided against venting the low tunnels in these early Spring months.  Conventional wisdom says to begin venting a low tunnel, or more specifically a greenhouse, when temperatures rise above 90 degrees F.  Experts say that plants won't grow above these temperatures.   Perhaps that is true for plant growth if these temperatures are sustained for long periods of time.   However, the temperatures under the low tunnels went above 120 and sometimes up to 130 and 140 during these months and there was not a single case of a wilting plant or leaf.  Figs, and probably other subtropical, mediterranean, and tropical plants can withstand and even thrive in these temperatures if the humidity stays high with those temperatures.   This is an extreme advantage to the Espalier method because the floating row cover can stay on the espalier until the fig reaches the height of the row cover.

One of the things I would do differently when planting the figs is to hill the rows where the figs were planted.  I would do this because our soil can be quite wet, even during the dry months, and this slight ridging would help keep the base of the figs dry.  I would also grow the cordon slightly higher off the ground.  I would probably do 2-3 inches.  The reason for this is that any figs that form along the cordon may touch the ground and if the humidity is high during the time they're ripening, they will rot if they are touching the woven landscape fabric.   One of the changes I made from the original proposal was the choice to not mulch the cordons.  I did this because I wanted to determine if the figs would survive without this extra protection.  So far this has been the case and I propose that orchards farther north employ mulching as an extra preventive measure. 

Another change I would make is planting figs from quarts or gallons.  Planting from cells proved to be too small and we had to baby some of the plants through the first year.  Since these plants would be farther along in the process, I would prune the apical bud in the pots so that low branches would form allowing the espalier to be partly established at the time of planting rather than afterwards. 

One of the possibilities I see with protecting the Japanese Fig Espalier with floating row covers, particularly for shorter season climates, is growing the espalier not as verticals, but merely as single cordons each year.  In places where one might not be able to protect the cordon for winter survival, I believe one could grow new fruiting cordons each year.  The cold hardiest figs will sprout new growth from the base if they die to the ground.   The advantage to growing new cordons yearly would be the ability to keep the floating row cover on during the spring and early summer.  During the height of the summer, the cover could be removed, but added back on in the fall for additional ripening time. In this way, the high tunnel could be densely planted because not as much space would be need per plant since the cordons would die to the ground yearly. 

 

Participation Summary

Education & Outreach Activities and Participation Summary

1 Tours

Participation Summary:

Education/outreach description:

This year the youtube channel will be started.   The channel will be titled Coastal Fig Company which is our nursery name.   Please follow along for updates to our progress. 

Learning Outcomes

2 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

Farmers are starting to realize the benefits of growing inside of low tunnels inside of high tunnels.  For us, the JapaneseJapanese Fig Tree Espalier begins to bud and leaf out in early March. Fig Espalier started to wake up around March 10th in the low tunnels. In contrast, the majority of figs planted in the ground in zone 7a and 6b will wake up in early May.  The picture below was taken on March 11th.  This is at least 7 weeks before the in-ground fig trees begin to wake up. We believe this head start of 7 weeks will produce significantly higher quality and earlier fruit than their in ground open field counterparts.  

We also believe that attitudes are changing toward some standard growing practices.  During the early months of Spring, temperatures under the low tunnels were reaching 130 degrees Fahrenheit.  There was not a single incident of leaf burn or plant die back.  Traditional wisdom and every greehouse book recommends venting above 90-100 degrees.  We did not find this necessary. Of course we opened the sides of the high tunnel eventually in mid June but we found that figs in particular can withstand the extreme temperatues for a few hours a day as long as the humidity stayed high within the tunnel. 

 

 

Project Outcomes

Project outcomes:

One possible outcome of this project is seeing an increase in numbers of individuals and farmers growing figs inside of high tunnels using low tunnels. I would also like to see farmers trying to grow this crop even farther north than Pa as a single rejuvenated cordon or mulching the cordon yearly to see the success rate of survival.  I hope to see a farmer intercropping lettuce, kale, or spinach between the rows of the Japanese Fig Espalier during the winter months for an early spring harvest. 

 

 

Assessment of Project Approach and Areas of Further Study:

 

 

Information Products

    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.