Ginger Spacing in High Tunnels for Maximum Yields

Progress report for FNE21-980

Project Type: Farmer
Funds awarded in 2021: $8,048.00
Projected End Date: 01/31/2023
Grant Recipient: Rustic Roots Farm
Region: Northeast
State: Maine
Project Leader:
Erica Emery
Rustic Roots Farm
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Project Information

Project Objectives:

This project seeks to determine the most appropriate spacing of ginger rhizomes for the highest yield of fresh baby ginger. We will conduct this study for two growing seasons to establish a thorough set of data so our farm and future growers can make informed decisions about the best high tunnel spacing for ginger production. 

Objectives:

1)Research high tunnel- grown ginger using four in-ground test plots with four different spacing setups.  This set of data will demonstrate the spacing that will be the most efficient to use in high tunnels. For farmers looking to maximize their yield per row foot or dollar value per square foot of their high tunnel, this information will be vital. 

2)Research high tunnel grown ginger using three different fabric pot planting densities of ginger rhizomes. This set of data will determine yields based on the number of rhizomes present in each fabric pot. Other farmers can use this data to compare to the in-ground plots to determine if pots have the capacity to yield more net profit based on intensively planting in a controlled environment. 

Introduction:

Fresh ginger presents both an opportunity and a challenge for Maine growers. In addition to its culinary uses, research has shown the health benefits of consuming ginger. In particular, a recent study by the University of Virginia has demonstrated that the fresh, baby ginger grown in our region presents the most health benefits. Consumer demand for this popular spice is increasing in the United States and consumers have demonstrated a willingness to pay a premium price for locally-grown. Per pound, ginger yields our highest gross sales. At the same time, ginger is a relatively expensive crop to grow. Seed ginger is expensive and sometimes challenging to source. Its growing season is long and it requires dedicated space and infrastructure to germinate and grow. Baby ginger requires approximately 8 months to grow, while our region can only support 4-5 months of optimal growing conditions, particularly without the use of greenhouses. Our experience in growing ginger shows that it can be done but more data about rhizome spacing for optimal yields needs to be studied to increase yields and profits.

Given that ginger is a relatively new and lucrative crop to the Northeast, more growers are looking to add this enterprise to their operations. Due to the demands of this tropical crop and our own short growing season, the most viable growing method is within a high tunnel. This presents its own challenges as space is a limiting factor. During our own research for growing ginger the past two years, we found a wide range of seed spacing recommendations. Hawaii Clean Seed, one of the major suppliers of seed ginger, recommends between 4” and 10” seed spacing in either single or double rows. Not a very exact recommendation. Like many growers with finite space, we want to know what is the most amount of ginger that can be grown in the least amount of space, thus the importance of establishing best practices for successful high tunnel ginger growing in New England.  

Our study will examine how ginger rhizome seed spacing within our high tunnel impacts ginger yields. Across two seasons, we will plant similarly-sized ginger rhizomes at various spacing in-ground in beds and above-ground in fabric pots. This will allow us to compare planting piece weight to harvest yield based on the spacing made available to the rhizome. Water, soil amendments, and season length will remain the same for all test ginger. At the end of each season, we will compile yield data for each seed spacing set. Our goal is to identify the optimal spacing to maximize yields and develop recommendations for other growers in our region.

Cooperators

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  • Dave Fuller - Technical Advisor

Research

Materials and methods:

Objective #1 Materials and Methods

  • Ginger rhizomes will be cut and weighed into 2 oz seed pieces. The seed pieces will be placed in 1020 plastic trays in a sterile coco coir medium. These 1020 trays will be placed in the germination chamber. The germination chamber will be set to 80 degrees and the rhizomes will be left to germinate and sprout for 8 weeks. 
  • There will be four research plots in total. All research plots will be 25’ long with 36” bed tops located in a high tunnel greenhouse at our farm. 
    • Research Plot #1 will be set up for a single row of planting with rhizomes at 4” spacing. This plot will have 75 rhizomes planted. 
    • Research Plot #2 will be set up for a single row of planting with rhizomes at 8” spacing. This plot will have 37 rhizomes planted. 
    • Research Plot #3 will be set up for double row planting with rhizomes planted at 4” spacing. This plot will have 150 rhizomes planted
    • Research Plot #4 will be set up for double row planting with rhizomes planted at 8” spacing. This plot will have 75 rhizomes planted. 
  • The research plots will all be planted by mid-May on the same day. At the time of planting, the rhizome will be planted into a 6-inch trench with compost, fertilized with fish emulsion, and covered with soil. 
  • Research plots will be irrigated daily by overhead emitters set on a timer. Duration will be 1-3 hours per day based on high tunnel temperature.
  • These research plots will be hand cultivated for weeds every other week for the duration of the growing season. 
  • Plots will be fertilized every other week for the duration of the growing season. 
  • We will hill the research plots twice over the course of the growing season, once in early July and again in late August. 
  • Harvest will occur between October 1st and October 10th. All research ginger will be harvested on the same day. We will harvest, wash the ginger, and then weigh and record the ginger hands without the green stalks to determine the yield in weight per plant. 
  • Our final data analysis will be to determine an average weight for each ginger hand and an average ratio of rhizome weight to ginger hand weight for each of the four research plots. 

 

Objective #2 Materials and Methods

  • Ginger rhizomes will be cut and weighed into 2 oz seed pieces. The seed pieces will be placed in 1020 plastic trays in a sterile coco coir medium. These 1020 trays will be placed in the germination chamber. The germination chamber will be set to 80 degrees and the rhizomes will be left to germinate and sprout for 8 weeks. 
  • There will be three different data sets collected from the fabric pot research:
    • Set #1: five 20 gallon fabric pots will have a single ginger rhizome each.
    • Set #2: five 20 gallon fabric pots will have two ginger rhizomes each. 
    • Set #3: five 20 gallon fabric pots will have four ginger rhizomes each. 
  • The growing medium for the fabric pots will be 3 parts ProMix ORGANIX and one part cow manure-based compost. 
  • The fabric pot research sets will all be planted the same day by mid-May. At the time of planting, the rhizome will be planted into 6-inch holes in the fabric pot, fertilized with fish emulsion, and covered with soil.
  • Fabric pot research plots will be equally irrigated daily by emitter ground stakes set on a timer. Duration will be 1-3 hours per day based on the high tunnel temperature.
  • These research fabric pots will be hand- cultivated for weeds every other week for the duration of the growing season. These research plots will also be fertilized every other week for the duration of the growing season. 
  • We will hill the research plots twice over the course of the growing season, once in early July and again in late August. 
  • Harvest will occur between October 1st and October 10th. All research ginger will be harvested on the same day. We will harvest, wash the ginger, and then weigh and record the ginger hands without the green stalks to determine the yield in weight per plant. 
  • Our final data analysis will be to determine an average weight for each ginger hand and an average ratio of rhizome weight to ginger hand weight for each of the three fabric pot research sets. 
Research results and discussion:

One major change that we made to our methods was that we intended to use 2 oz rhizome pieces but ended up using pieces that averaged 1.6 oz. This was due to the way the seed pieces were sent to us from the seed company. The overall weight of rhizomes planted was lower than what we intended. 

  2021 SEASON
  Planted (oz) Harvested (oz) Growth Increase (%)
8" Single Row 46.36 310.24 569.20%
4" Single Row 92.72 476.8 414.24%
8" Dbl Row 92.72 615.68 564.02%
4" Dbl Row 185.44 690.24 272.22%
TOTAL 417.24 2092.96 416.82%
     
  Planted (oz) Harvested (oz) Growth Increase (%)
Container #1 2.32 19.52 741.38%
Container #2 4.64 34.24 637.93%
Container #3 2.32 27.2 1072.41%
Container #4 4.64 34.24 637.93%
Container #5 1.16 17.28 1389.66%
Container #6 1.16 0.112 -90.34%
Container #7 2.32 33.76 1355.17%
Container #8 2.32 29.76 1182.76%
Container #9 4.64 25.28 444.83%
Container #10 1.16 22.24 1817.24%
Container #11 4.64 21.44 362.07%
Container #12 1.16 4.96 327.59%
Container #13 2.32 34.72 1396.55%
Container #14 1.16 23.36 1913.79%
Container #15 4.64 35.52 665.52%
TOTAL 40.6 363.632 923.63%

 

In this study, we measured (1) harvested ginger by  weight (oz) and (2) ginger growth increase (%) in relation to seed spacing in both in-ground research beds and fabric research containers. The overall goal of this project is to determine ideal spacing for maximum yield based on a combination of these two values. 

 

In our 2021 research beds, seed ginger was planted in four 25’ plots: 8” single row, 4” single row, 8” double row and 4” double row. The least intensive planting, 8” single spacing produced the least total harvested ginger by weight (310.24oz) and the greatest growth increase (+569%). Conversely, the most intensive planting, 4” double spacing, produced the greatest harvested ginger by weight (690.24oz) and the least growth increase (+272.22%). By comparison, the two intermediate planting rates resulted in more similar results: 4” single spacing produced 476.8oz of harvested ginger and 414.24% growth increase; 8” double spacing produced 615.68oz by weight and an increase of 564.02%. It should also be noted that the latter two spacing methods contained a near equal weight of initial seed ginger.

 

In our 2021 research containers, seed ginger was planted in fifteen 20 gallon fabric pots at a rate of 5 containers each of 1 seed, 2 seed or 4 seed. Pots were randomly arranged. The total harvested ginger by weight ranged from 4.96oz to 34.72oz and the average growth increase of all containers was 923.63%. Of the five containers containing 1 seed, three resulted in a growth increase greater than the average, one resulted in less than the average, and one pot failed completely. For the containers planted with 2 seed, one resulted in below the average whereas four were above average. All five containers with 4 seed resulted in growth increases below the average.

 

Over the course of the 2021 growing season, we made several changes from our initial project design. Originally, we proposed a larger individual seed ginger size. However, we opted to have the seller pre-cut seed ginger into plantable pieces. As a result, the average size of the seed material received was much smaller. After weighing and sorting our 50lbs of ginger, we opted for an average individual size of 1.16oz. While it is possible that smaller seed may result in smaller yields, this size was a good representation of the ginger sent by the grower. Another option would have been to order the ginger uncut by the grower, allowing us to cut into larger sized ourselves. While we have done this in the past, we felt that this would result in too much waste and possibly less viable seed since we are not very experienced at ginger cutting and curing.

 

Another divergence from our proposal was in our irrigation method. Initially we planned to water research beds and research containers by overhead sprinklers and drip stakes respectively. After two weeks, we observed that our containers were receiving more water than we desired and we worried about rot in our seed. In order to address this, we moved our containers closer to our beds so that they could receive the same overhead watering. For the remainder of the season, all research ginger received the same amount of watering.

Research conclusions:

In this study, we sought to determine the ideal spacing of seed ginger in a greenhouse for maximum yield in the least amount of space. This is important because ginger is a high value crop best planted in a greenhouse. Small farms, such as ourselves, have limited greenhouse space and must balance valuable real estate among many crops. For this study, ginger was planted in-ground at four different spacing patterns. Ginger was also planted in fabric containers at three different seeding rates. All ginger was harvested on the same day at the end of the season and then weighed by individual in-ground plot or container.

 

Though this was the first of our two-season study, the initial data has revealed some interesting trends. In regards to the research beds, though the 8” single row plot produced the greatest percentage growth increase from seed to harvested ginger, this came at a cost total harvested weight, ie. ginger at this spacing grew very well but at the cost of total yields because the initial planting was so small. In contrast, the 4” double row plot produced the greatest yield by weight, likely due to it being the most heavily planted. However, this plot had the lowest percent growth increase, suggesting that perhaps ginger grew less ideally in such a heavily planted area.

 

Of the remaining plots, despite nearly equal starting seed weight, 8” double row was greater than 4” single row in both harvested weight and percent growth increase. These results suggest that ginger is again benefitting from greater space between plants. In comparison to the 8” single row plot, 8” double yielded nearly twice the harvested weight and just below the highest percent increase. Compared to the 4” double row, 8” double again fares very well with nearly the same amount of harvested ginger by weight and more than double the percent growth increase.

 

Based on the 2021 data, an 8” double row has emerged as the most optimal spacing for growing ginger in a greenhouse. This planting pattern allows for the most amount of ginger to be planted without overcrowding the plants. Such overcrowding may lead to smaller yields due to competition for water, light and nutrients. Similarly, in our research containers, grow pots that contained two pieces of seed resulted in the highest percent growth increase compared to those with one or four seed pieces. Though total yield by weight was higher in some of the 4 seed pots, those with 2 seed again appear to strike the balance between yield and maximum increase from seed to harvest. We look forward to replicating our study in the 2020 season to learn whether these trends will continue.

Participation Summary

Education & Outreach Activities and Participation Summary

1 Workshop field days

Participation Summary:

12 Farmers
4 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:

Our farm hosted a field day tour of our farm operations and we spent a significant amount of time in our ginger tunnel talking about our ginger production practices. This happened on August 5th, 2021. The groups involved were Maine Agriability and the Maine Veteran Farmer Boots to Bushels group. There were three service providers and 12 farmers on the tour. The 4th service provider referenced above is our technical advisor, Dave Fuller. 

Learning Outcomes

12 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:

Production methods

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.