From 2016-2018, a SARE partnership project was conducted to evaluate leafy green production in the Eastern Panhandle region of West Virginia. This region of West Virginia is the fastest growing area of the state and is adjacent to large, diverse population areas. A unique characteristic of this region is the availability of agricultural land. As retail markets become more saturated, growers are seeking regional wholesale markets such as hospital and school districts. The objectives of this project were to evaluate the feasibility of year-round head lettuce and spinach production; establish best management practices for leafy green high tunnel production; train a cohort of new growers; and establish a relationship between growers and regional institutional buyers.
Approximately 100 varieties of lettuce and 20 varieties of spinach were screened for year-round production resulting in selection of eight adaptable varieties for year-round production of head lettuce and five varieties of spinach. The most versatile lettuce cultivars evaluated in this trial included ‘Alkindus’, ‘Buttercrunch’,’Magenta’, ‘Cherokee’, ‘Sierra’, ‘Tropicana’ ‘Green Forest’, ‘Breen’, ‘Salvius’ and ‘Monte Carlo’. The most versatile spinach cultivars evaluated in this project included ‘Abundant Bloomsdale’, ‘Mandolin’, ‘Scorpius’, ‘Unipack-12’, ‘Violin’ and ‘Regiment’. Growers were trained on variety selection, production practices, harvest, postharvest handling and marketing to a Veteran’s Administration Hospital and local school district. Most growers received an average lettuce price of $2-2.50/lb. from the institutional buyers which was significantly above the estimated break even price of $0.50/lb. The project established a successful connection between producers, WVU Extension and institutional food service directors.
Outreach took the form or workshops around the state, two fact sheets and a poster at a scientific horticultural conference. The results of the project will be replicated in other regions of West Virginia which have limited wholesale market opportunities.
The objectives of this project were to: 1) identify adapted and versatile cultivars (or varieties) of head lettuce and spinach for year-round production in West Virginia; 2) Evaluate sequential planting of lettuce and spinach within the high tunnel; 3) establish a relationship with the culinary and nutrition staff at the Martinsburg, WV VA Hospital; 4) train 2 cooperating growers on winter leafy green production and marketing to institution markets.
The Eastern Panhandle region of West Virginia is an eight county area with a base population of approximately
260,000 residents. This region is the fastest growing area of West Virginia and adjoins the Northern Virginia, Washington, D.C. and Baltimore metropolitan areas with approximately eight million residents. In addition to access to large consumer markets, the region has fertile soils and a microclimate suitable for production of many specialty crops. Historically, the area has been a commercial tree fruit production area. Many of the commercial orchards have consolidated or have been subdivided for commercial development within the past decade. In addition, approximately 30 new high tunnels have been constructed primarily through the USDA-NRCS Seasonal High Tunnel Program in the Eastern Panhandle. To keep agriculture sustainable within this region, a more diverse and intensive food production system with year-round market outlets must be adopted.
In West Virginia, approximately 35 county school districts out of 55 counties statewide have been purchasing some food products from local producers. In addition, regional hospitals have expressed an interest in buying
local products. Vegetables in demand by institutions include leafy greens, broccoli, tomatoes, squash, cucumbers and melons (B. Leigh, Personal Communication).
Leafy greens are a diverse group of cool season vegetables which includes popular vegetables such as kale, spinach, Swiss chard and lettuce. Leafy green vegetables have a strong demand by all school districts and some hospitals in West Virginia and can be profitable crops for new producers.
There is tremendous opportunity for expanded production and marketing of specialty crops including leafy greens in the Eastern Panhandle region by using seasonal high and low tunnel structures. However, there is a deficit of technical information related to production, scheduling, postharvest handling, food safety, economics and marketing of specialty crops using protected environment structures such as high and low tunnels.
The objective of this project is to create an expanded capacity of information related to production, scheduling, economics, food safety and postharvest handling of select leafy greens in the Eastern Panhandle of West Virginia for institutional markets such as schools and hospitals.
From 2015-2018, 90 varieties of Bibb, Romaine and Crisphead lettuces and 20 varieties of spinach were evaluated for marketable yield, quality, color and stress tolerance. Trials were conducted within high tunnels located at the WVU Kearnesyville Research and Education Center and cooperators in Hardy and Berkeley Counties, West Virginia. Each variety was replicated a minimum of three times in a randomized complete block design within each high tunnel. The high tunnels were 24-30 ft. wide x 72 ft. long. The lettuce was seeded into 128-cell or 228-cell plug trays filled with ProMix BX media and grown in a high tunnel or greenhouse at WVU. The plugs were allowed to mature for 3-4 weeks in a greenhouse before planting within the high tunnel. To demonstrate that high tunnels can be used to grow lettuce and spinach plugs, the transplants were grown as transplants in unheated high tunnels in 2017-18 before planting within the high tunnel for harvest as a fall, winter or spring cash crop.
Lettuce planting dates within each high tunnel were April, October, and November of each year. These planting dates provided an evaluation of the leafy greens for spring/summer; summer/fall and fall/winter. The plants were spaced 9 to 12 inches within row on a 3-4 row bed. Drip irrigation of the lettuce was used at all evaluation sites. Each bed was covered with black or white embossed plastic mulch with two drip lines per bed. The soil pH at each planting location was 6.2-6.8. Preplant nitrogen, phosphorus and potassium were applied based on recommendations from the Mid-Atlantic Vegetable Production Guide. No supplemental fertigation was applied through the drip irrigation system. The lettuce was irrigated based on soil moisture tension readings from a tensiometer placed at rooting depth within the bed. Irrigation frequency averaged three times per week through spring-fall and was curtailed after late November for winter production.
The center row of each bed was harvested for data collection. Fresh weight, head diameter, color and quality was measured. Pest interactions were noted through each growing season. Bolting (i.e., reproductive growth) was noted as well as physiological tip burn incidence. Each variety was harvested approximately twice as a once-over harvest. A subsample of varieties was placed in a controlled environment cooler (34°F) for approximately 4-5 weeks to evaluate post harvest quality.
Spinach was established as direct-seed or transplants within high tunnels for spring and fall/winter evaluations. Spinach was seeded in a 4-row bed within a single layer high tunnel at the WVU Kearneysville Farm in early March, 2017. The soil at this farm is a silt loam with a pH of 6.8. Prior to seeding, 46 lbs. /1000ft2 of 5-4-3 HarmonyÒ fertilizer was applied and tilled into the beds. The spinach was hand-seeded with each seed ≈1 inch apart in-row and 6 inches between rows. Each plot was 6 ft2. In addition, spinach was transplanted within a double-layer high tunnel in Hardy County, WV in November, 2016. The transplanted spinach was spaced 4 inches apart in a 4-row bed covered with black plastic mulch. Twenty varieties of spinach were evaluated for yield and quality. Two sequential harvests were made per variety. The cut leaves were sorted and fresh weight recorded. In addition, color, flavor and overall quality were subjectively rated. Each variety was replicated in a randomized complete block design.
Institution Markets and Growers:
The Institutional partners in this evaluation were the Veterans’ Administration Hospital in Martinsburg, West Virginia and the Hardy County, West Virginia School District. The contact representatives were Ms. Barbara Hartmann RD and Ms. Bekki Leigh The individual growers who partnered with Dr. Jett on this project were introduced to these representatives. The representatives conducted site visits of each farm and negotiated with the growers on specific volume and grade standards required. A vendor payment system was established with each grower. Dr. Jett conducted site visits through the growing season and collected data on cultivars. Discussion and demonstrations with each grower on food safety, harvest and postharvest handling was performed.
Field days at growers farms and the WVU Kearneysville Farm were conducted in 2016-2017. In 2018, an Eastern Panhandle Growers’ Conference was started and the results of the leafy green project were presented to new and interested growers. Representatives from the VA Hospital presented information to growers on selling to their institution. The field fays and conference created relationships between new producers and cooperating growers for this SARE Partnership project and the participants in this project will present information at other state and regional conference to duplicate this model throughout West Virginia.
Lettuce can be grown year-round in West Virginia. To achieve high marketable yield and quality, cultivars must be selected for the specific season of the year. Open-field production of lettuce is challenging given the erratic climate observed in the Mid-Atlantic region during spring through fall. High tunnels, however allow the grower to have some control over the growing environment resulting in more predictable quality and yield.
The research from this SARE Partnership Grant has identified foundation cultivars for year-round production of lettuce and fall-spring production of spinach. Best Management Practices for lettuce production including cultivar selection, row cover management, economics and pest management within high tunnels in the Mid-Atlantic U.S. were outcomes of this project.
Lettuce Cultivar Selection:
Cultivar selection is one of the most important decisions any specialty crop grower can make. Lettuce is a cool season vegetable crop which has an optimal temperature for growth of 65°F. Significant deviations from this temperature can reduce marketable yield and quality. Moreover, physiological disorders such as tip burn can be exacerbated by high temperature and humidity.
During this project duration, extreme low (0F) and high (98F) temperatures were observed during lettuce production trials.
One of the objectives of this project was to identify versatile and adaptable varieties of head lettuce for year-round production. Varieties which had significant marketable yield and quality during high and low temperature were identified. Within the Crisphead class of lettuce, ‘Sierra’ which is a green-leaf variety had excellent heat and cold tolerance. A red-leaf Crisphead, ‘Cherokee’ was extremely versatile and had a color intensity which changed with ambient temperature. ‘Magenta’ is a red-green Crisphead lettuce with excellent yield and quality in high and low ambient temperatures. No tip burn was observed on any of these varieties in cold or hot weather. ‘Red Cross’ is an excellent Bibb lettuce with red coloration. ‘Alkindus’ is also a very high yielding, red Bibb lettuce. ‘Buttercrunch’ would be a good choice for a green Bibb lettuce.
Romaine lettuce tends to show tip burn more often than other types of lettuce. Our trials with romaine lettuce revealed ‘Monte Carlo’ Salvius’, ‘Green Forest’ and ‘Breen’ as excellent romaine lettuce for year-round production. The EZ-leaf types included many of the Salanova varieties which can be used as a loose-leaf lettuce or as an intact head. Our trials indicated that that varieties such as ‘Hampton’ and Salanova buttercrunch (red or green) and Salanova oakleaf (red or green) were excellent. ‘Tropicana’ and ‘Starhawk’ are excellent, loose-leaf lettuce with exceptional heat and cold tolerance. Minimal evaluations of iceberg lettuces were performed but ‘Crispino’ and ‘Declaration’ were high yielding iceberg lettuce varieties.
Spinach Cultivar Selection:
UniPack 12’, ‘Regiment’, ‘Violin’ ‘Cello’ and ‘Mandolin’ were excellent cultivars, exhibiting both high yield and quality. ‘Violin’ was the highest yielding smooth leaf cultivar while ‘Regiment’ and ‘Unipack 12’ were the highest yielding savoy cultivars. In late spring, ‘Scorpius’ was observed to have heat tolerance (i.e., no bolting) and thus, could possibly be grown as a summer spinach. ‘Regiment’ and ‘Emperor’ were productive during the winter season. ‘Red Kitten’ had red veins and can be blended with traditional green spinach for a color mix.
Sequential Planting of Lettuce:
For continual harvest of lettuce, we discovered that sequential planting every 3-4 weeks from February through November will facilitate an even supply of lettuce for institution markets. Lettuce planted in October and November was harvested through deep winter (January-February). Lettuce can be reestablished beginning in February.
Temperature and Row Cover Management:
The optimal temperature for production of head lettuce is 65-75°F. Thus, venting should be controlled to reach this temperature range. Most head lettuces will grow if the temperature is >40°F. When air temperatures exceed 85°F for extended periods of time, the lettuces will often bolt (i.e., produce a seedstalk), develop tipburn or become bitter. A 30-50% shade cloth can be used to reduce air temperature within the high tunnel. Summer lettuce should be grown on white plastic mulch and irrigated daily. Row covers should be used to modify temperatures for lettuce growth. A 0.8-1.0 oz. /yd2 row cover is recommended. When the minimum (night) temperatures are forecast to be lower than 40°F, row covers should be applied to the lettuce crop. When the ambient temperature is 30-40F, 2 layers of a 0.8-1.0 oz. row cover can be used. If the ambient temperature is below 20F, 2-3 layers of 0.8-1.0 oz. row cover can be used. The following morning (temperature permitting) the row covers can be removed. Row covers are applied 2-3 hours before sun set in the fall and winter. Avoid growing lettuce for extended periods of time under row cover since this will often produce tip burn symptoms on the leaves.
Pest Management of Leafy Greens:
Common pests of lettuce and other leafy greens grown within high tunnels include aphids, slugs and grasshoppers. Routine scouting of the rows were done to detect aphid “hot spots”. These areas were treated before the pest invades the rest of the crop. Red leaf varieties of lettuce seem to be more attractive to aphids. There are several organic and “soft” pesticides for aphid control. Slugs were controlled with iron phosphate baits while larger insects such as grasshoppers or crickets were excluded with Protek Net exclusion netting.
Economics of High Tunnel Lettuce:
A 1000 ft2 of bed space will accommodate production of approximately 1900 heads of lettuce. Each lettuce cropping cycle is 65-80 days. Enterprise budgets of high tunnel head lettuce production revealed a breakeven price of $0.50/head of lettuce. A 30 ft. x 96 ft. high tunnel with 1800 ft2 of usable bed space could produce net revenue of $1600-2500/1000ft2 per lettuce crop cycle.
Year-round production of head lettuce and spinach can be achieved by use of high tunnels in West Virginia. Synchronizing production with institution markets is critical. Sequential planting of head lettuce every 3-4 weeks ensures a steady supply for institution markets with most high tunnel production systems. Spinach can be planted every month from August through early April. Spinach produces more gross revenue per square foot than head lettuce, but requires relatively more postharvest handling.
Matching suitable adapted varieties with the season of the year is important when producing leafy greens for institution markets. Mulch type also affects growth and quality of head lettuce and should be used to reduce heat stress or absorb heat. Shade cloth (47-50%) can be used in mid-June through early September for summer lettuce production.
Lettuce for high tunnel production is spaced 9-12 inches within row in a 4-5 row bed. Head lettuce is harvested when the head diameter is greater than 6 inches. Average weights for head lettuce are 0.5-1.25 lbs./head. The average production cycle for head lettuce is 75 days in a high tunnel from planting to harvest.
When working with an institutional buyer, there may be some flexibility in postharvest handling. If the culinary staff at the school or hospital will do washing, the grower must simply harvest, trim and package at the farm and transport to the facility. Unwashed lettuce can be stored for up to 4 weeks at 33-36F. The grower must build a relationship with the culinary staff or food service personnel at the institution. A farm visit or inspection must occur prior to selling or delivery. Working with the institution to register as a vendor and meet specific criteria for size, grade and uniformity is important.
The case studies created from this SARE Partnership Grant will be replicated across West Virginia. The cooperating growers in this project and I have been invited to the meeting of Registered Dieticians for Hospitals and Schools in West Virginia in 2019 to discuss the output from the project and to try to replicate our project across West Virginia with both hospitals and other school districts.
Education & Outreach Activities and Participation Summary
ASHS181In 2017-18, three on-farm field days were conducted. Leafy green production, pest management, postharvest handling and marketing were discussed with attendees. Data from the research trials was presented at 3 multi-state meetings with over 200 attendees. Two fact sheets were created which included the “Season Extension Lettuce Guide” and “High Tunnel Spinach Production”. At the 2018 American Society for Horticultural Science Annual Meeting, this project summary was presented as a poster.
variety selection, pest management, harvesting, postharvest handling
The two cooperating farmers involved in this Partnership Grant have been acquiring skills related to extended season leafy greens production and marketing. The growers have become aware of what makes a high quality lettuce or loose-leaf green such as spinach. Planting dates for uninterrupted production have been adopted. Grower-cooperators have become more knowledgeable on essential Best Management Practices such as variety selection, fertilization, irrigation, pest management, harvesting, food safety and postharvest handling. We have other groups of high tunnel producers in West Virginia who will use the important output from this project. Project participants are meeting with Food Service Directors from other regions of West Virginia to replicate this Farm-to-Hospital project.
In West Virginia, like the rest of the planet, we are in a period of climate change. West Virginia growers must adapt to these changes by adopting new crops and new technologies. Anecdotally, in the 3.5 year duration of this project, we experienced 2 extreme weather events (summer and winter) which damaged the high tunnel structures used to evaluate the production of leafy greens. Each time, we rebuilt the structures, but these events were part of a series of extreme and erratic weather experienced each month of the growing season. The use of high tunnels for this project demonstrates the effects of technology which buffers or adapts to climate change. Moreover, selecting genotypes of leafy greens which are adapted to the specific growing season is another significant long-term output from this project. The results of this project have immediate application to other regions of West Virginia. The next stage of research is to evaluate methods which make leafy green production more efficient. Ideally, we need to evaluate more treatments for growing leafy greens including low-tech hydroponics, soil heating systems and supplemental lighting. Moreover growers need to be organized into supply and marketing cooperatives which will enable them to access more regional wholesale markets.