High Tunnel Production Research Articles

Sustaining Soil Health in High Tunnels: A Paradigm Shift toward Soil-centered Management

This review was conducted to synthesize current knowledge, learn producer and Extension specialist perspectives, and identify gaps in understanding of the role of soil health in sustaining production in high tunnel (HT) systems. This synthesis includes findings from scholarly resources related to soil health in HTs, including research and Extension-based literature, perspectives from experienced HT producers and technical assistance providers, and the direct observations of a broad network of university research and Extension personnel working with HTs. Findings are intended to identify knowledge gaps and additional research and Extension resource needs of greatest priority to the HT producer community and technical assistance providers that support them at the time of publication. A review of 68 research articles and 58 Extension resources was conducted. Focus group interviews were conducted with small groups of experienced HT farmers in four regions of the eastern half of the United States, with in-depth farm case studies conducted in individual farmers in three of these regions. Growers across regions identified soil fertility management, soilborne diseases, soil compaction, and lack of consistency of soil analyses specific to HTs as the greatest soil-related challenges to HT production. Research and resources for technical assistance providers on mitigation strategies to remediate yield-limiting HT soil conditions, such as excessive soil salinity and high pathogen populations, were also lacking. As such, process-based research on techniques such as leaching, soil steaming, solarization, and anaerobic soil disinfestation in tunnels that consider short- and long-term costs, benefits, and effects on soil and plant productivity should be prioritized in the future when considering the impact of HT production on soil health. Interviews also indicated a need for networking opportunities for technical assistance providers across agencies (e.g., Natural Resources Conservation Service, Extension, nongovernmental organizations). Despite a high and increasing rate of adoption, there is currently a lack of information about maintaining HT systems. Given that HTs play a critical and growing economic role for specialty crop growers throughout the eastern United States, comprehensive intervention across the research–Extension spectrum to sustain productivity in HT systems is recommended.

Specialty Melons Grown under High Tunnel Conditions Yield Good to Excellent Internal Quality

Interest in local foods, especially locally grown fruit, is increasing. High tunnel vegetable growers are strategically poised to meet this demand by growing specialty melons (Cucumis melo). Although specialty melons are commonly grown in high tunnels in other parts of the world, it is an uncommon practice in the midwestern United States. The objectives of this study were to evaluate 10 specialty melon cultivars for high tunnel production and measure fruit yield and internal quality. Fruit of the cultivar Eden’s Gem yielded the greatest number of marketable fruits per plant; however, these melons are small and have a loose cavity. Fruit of the cultivars Honey Orange and Divergent yielded the largest marketable fruit per plant with tighter cavities; however, the cavities were large. All cultivars had good to excellent internal quality in terms of sugar content. The production of specialty melons in the high tunnel was successful, resulting in the production of melons with good to excellent internal quality, and several yielded three to four marketable fruit per plant. Implementing a strong pest management plan for cucumber beetle (Diabrotica undecimpunctata howardi) and powdery mildew (Erysiphe cichoracearum, Sphaerotheca fuliginea) is recommended to prevent yield loss, especially in locations such as the Midwest, where cucumber beetles often vector bacterial wilt (Erwinia tracheiphila).

Daily Light Integral, but Not the Photoperiod, Influences the Time to Flower and Finished Quality of Dianthus Specialty Cut Flowers

Because of the burgeoning year-round demand, greenhouse growers across the United States are increasingly becoming interested in producing specialty cut flowers for local and regional markets. However, outdoor or high tunnel production is not possible year-round in northern latitudes because of low temperatures and radiation intensities experienced during the winter and early spring. Additionally, natural short days in these seasons can limit which photoperiodic crops can be grown. Thus, our objectives were to quantify the influence of the photoperiod and daily light integral (DLI) on greenhouse-grown dianthus ‘Amazon Neon Cherry’ and ‘Amazon Rose Magic’ (Dianthus barbatus interspecific) cut flowers during the young plant and finishing stages. Seeds of both cultivars were sown under 9-, 10-, 11-, 12-, 13-, 15-, or 16-hour photoperiods and a DLI of either ≈5 or 10 mol⋅m−2⋅d−1. After 4 weeks, seedlings from several young-plant photoperiods were distributed across 11-, 12-, 13-, 14-, 15-, or 16-hour photoperiods or a 4-hour night interruption (NI) under a DLI of either ≈5 (low) or 14 (moderate) mol⋅m−2⋅d−1 for finishing. The young plant photoperiod generally had a statistical, but not commercial, influence on development and finished cut flower quality, whereas a 16-h finishing photoperiod marginally hastened development compared with an 11-hour finishing photoperiod. Additionally, stems were 11 to 13 cm longer when finished under the 16-hour photoperiod compared with those finished under the 11-hour photoperiod. Day length minimally influenced the time to flower and harvest, indicating a day-neutral flowering response. However, plants finished under a moderate DLI reached visible flower bud and were harvestable 9 to 10 days earlier than those finished under a low DLI. Additionally, ≈99% of cut flowers finished under a moderate DLI were harvestable, whereas only up to 32% and 57% of dianthus ‘Amazon Rose Magic’ and ‘Amazon Neon Cherry’, respectively, finished under a low DLI were harvestable. Although finished stem lengths were comparable between DLI treatments, cut flower stems were up to 29.6% thicker under a moderate DLI. These findings indicate that high-quality greenhouse-grown dianthus ‘Amazon Neon Cherry’ and ‘Amazon Rose Magic’ cut flowers can be produced when grown under any photoperiod between 9 and 16 hours for 4 weeks (during the young plant stage) and finished under any photoperiod between 11 and 16 hours or a 4-hour NI during finishing. If longer stems are desired, then plants can be finished under a 16-hour photoperiod. Young plants should be grown under a moderate DLI ≥10 mol⋅m−2⋅d−1 to promote biomass accumulation and reduce the young plant crop time. Additionally, plants should be finished under a moderate DLI ≥14 mol⋅m−2⋅d−1 to reduce crop time and increase stem thickness and yield.

Identification and Characterization of a Virulent Meloidogyne incognita Population Breaking Tomato Mi-1-Mediated Resistance in Indiana

High-tunnel production is increasing rapidly in the US due to its effectiveness in extending production seasons. Tomato is considered one of the most profitable crops grown in high tunnels. The elevated soil temperature and constant soil moisture in high tunnels lead to the buildup of root-knot nematodes (RKNs). Growing RKN-resistant tomato cultivars or grafting onto RKN-resistant tomato rootstocks is considered effective in managing RKNs. However, all of the RKN-resistant tomato cultivars or rootstocks carry the same resistance gene, Mi-1. This lack of diversity in resistance has led to the emergence of virulent RKN populations breaking tomato Mi-1 resistance. Here, we identified and characterized a virulent population of Meloidogyne incognita from a high tunnel in Indiana. The M. incognita population was confirmed as being able to infect and reproduce on two resistant tomato cultivars, Better Boy and Early Girl, carrying the Mi-1 gene, under a controlled environment at 24 °C. To our knowledge, this is the first report of a virulent M. incognita population breaking Mi-1 resistance in Indiana. Virulent M. incognita populations overcoming Mi-1 resistance were previously reported in California and Georgia in the US. This work emphasizes the importance of regularly monitoring RKN population virulence to sustainably manage the pest.

Short-term effects of brassica cover crops on soil quality indicators in organic production in high tunnels

The use of cover crops is aimed at sustaining soil health and productivity in the context of agricultural intensification and accompanying soil degradation. While cover crops have been extensively studied in field production systems, limited research has been conducted concerning their application in high-tunnel vegetable production. This study aimed to assess the effects of turnip (Brassica napus subsp. napobrassica (L.) Jafri) and swede Brassica rapa subsp. Rapifera Metzg) cover crops (CCs) on soil physicochemical and biological properties in an organic high tunnel system in southern Poland in 2017–2019. The planting sequence was as follows: winter cover crops/pumpkin/romaine lettuce/broad bean/chilli pepper. Soil analyses included measurements of bulk density, water capacity, soil aggregation, soil organic carbon (SOC), available soil nutrients, as well as microbial abundance and diversity. Rape crops produced a higher aboveground dry biomass (4.11 t ha−1) than swede (2.85 t ha−1), and the N content in their biomass was 101 kg N ha−1 and 75 kg N ha−1, respectively. The results presented that CC residue significantly contributed to soil organic carbon stock, retention of plant-available nitrogen, and improvement of soil physical properties, especially wet aggregate stability. Soils with the highest SOC concentrations were associated with the highest bacterial and fungal abundance. The most significant number of mesophilic bacteria was detected in the soil where turnip was grown as a cover crop (7.6 × 107 cfu g−1 DM soil). Moreover, a higher abundance of the tested nitrogen cycle bacteria was found in the soils after CC cultivation compared to the control soils, particularly bacteria reducing NH4 +-N and NO₃⁻-N. These findings highlight the importance of cover crop management practices in high tunnels, as they influence the composition of the total bacterial community and the abundance of N-cycling microbial guilds.

Effects of Soil Solarization and Grafting on Tomato Yield and Southern Root-knot Nematode Population Densities

High tunnel production has increased in the past 10 years in Kentucky with more than 1500 high tunnels constructed across the state. Tomato is the most popular and most valuable high tunnel crop per square foot. This has contributed to a lack of rotation and increased pressure from root-knot nematodes (RKN; Meloidogyne spp.). Infection by RKN leads to root galling and reduces the host plant’s ability to take up water and nutrients. Sustainable strategies are needed to manage increasing RKN populations for long-term health of high tunnel soils. Soil solarization is a nonchemical management strategy that has shown promise in other regions and in open field systems. Because tunnels are primarily used to produce high-value crops and are often used for season extension, solarizing during the off-season would be the most beneficial for growers because solarizing would require taking the tunnel out of production. The primary objective of this study was to determine whether springtime soil solarization in Kentucky high tunnels followed by use of resistant tomato cultivars is a viable and effective management strategy for RKN populations. Soil solarization was performed in two commercial high tunnels naturally infested with southern RKN (Meloidogyne incognita) for 2, 4, and 6 weeks and compared with a nonsolarized control. Soil temperatures reached during solarization were assessed at 7.6-, 15.2-, and 22.8-cm soil depth. After solarization, tomato was transplanted, including ‘Cherokee Carbon’ grafted onto RKN-resistant rootstocks ‘Fortamino’ and ‘Estamino’, RKN-resistant nongrafted ‘Caimon’, and susceptible ‘Cherokee Carbon’ as the control. The highest soil temperature achieved was 50 °C during 6 weeks of solarization at 7.6-cm soil depth compared with 38 °C reached in nonsolarized soil. Soil population densities of RKN increased each month after solarization and were generally lower after solarization with resistant tomato cultivars. The interaction of soil solarization and tomato cultivars was significant with respect to RKN densities in soil and roots. The mean RKN soil and root population densities in the nonsolarized, nonresistant treatment combination was significantly greater compared with all other treatments (P < 0.0001). Population densities of RKN were significantly higher in the nonsolarized control compared with solarized treatments (P = 0.0002). Nongrafted ‘Cherokee Carbon’ had significantly more RKN in surrounding soil compared with all other tomato treatments. Tomato yield was unaffected by soil solarization, but there were significant differences based on tomato cultivars alone; nongrafted ‘Cherokee Carbon’ yielded less than the resistant ‘Caimon’. Together, solarization and resistant cultivars reduced RKN population densities in soil and roots, which can provide growers with a nonchemical approach for long-term RKN management and high tunnel resiliency.

Comparison of organic eggplant yields under open-field and high tunnel production systems in Texas

High tunnel (HT) vegetable cultivation stands out as a superior choice when compared to open field (OF) production due to its numerous production benefits. However, intensive cultivation practices involving excessive use of inorganic fertilizer (IF) in HT production systems may lead to degradation of soil health, and ultimately poor crop yields. Therefore, this study investigated the effect of liquid organic fertilizer (LOF) and IF on growth and yield of eggplant (Solanum melongena L.) cultivars in HT and OF production systems. Two experiments were conducted in a split-split plot design with production systems (HT and OF) as main plot, fertilizers (LOF and IF) as sub-plot, and cultivars (‘Angela’ and ‘Jaylo’) as sub-sub plot factors. Throughout the growing season, daily average temperature and relative humidity were greater by 2 to 4 ​°C and 2 to 4%, respectively, under HT compared to OF conditions. In contrast, average daily light integral of HT decreased 18 to 24% compared to OF. Results from pooled growth and yield data of both experiments indicate HT produced 61% taller plants with 62% thicker stem diameter compared to OF. However, eggplant height and stem diameter did not differ significantly between fertilizer treatments or between cultivars. Due to a greater fruit count for each plant (63%) and average fruit weight (9%), total yield was 84% greater in HT compared to OF. Eggplant cultivar ‘Jaylo’ yielded 33% greater fruit count for each plant and 38% greater fruit yield compared to ‘Angela’ cultivar. However, no differences in fruit count, fruit weight, and the total yield were observed between LOF and IF. Results indicate that HT production offered a favorable microclimate which encouraged plant growth and greater fruit yield of eggplant compared to OF conditions. LOF and ‘Jaylo’ could be successfully used in organic eggplant production in HT and OF systems.

Yield of paste tomato cultivars using season extending high tunnel production practices in North Dakota’s short growing season

Yield of paste tomato cultivars using season extending high tunnel production practices in North Dakota’s short growing season

Plant Density Recommendations and Plant Nutrient Status for High Tunnel Tomatoes in Virginia

Open-field tomatoes in Virginia are traditionally planted in a single row with 2 ft (0.60 m) of in-row spacing, resulting in a plant density of 4356 plants per acre (10,890 plants/ha). However, there has been increasing interest among small and medium-sized farmers in high tunnel production. In order to be profitable, farmers must maximize their yield per unit area and take advantage of the potential benefits of producing under high tunnels. A common approach under greenhouse conditions is to increase the planting density to enhance yield per area. However, high tunnel farmers often extrapolate open-field practices to their high tunnels as they believe both systems are closer related together than to greenhouse production. In those cases, high tunnel farmers could potentially be neglecting yield increases due to their planting density selection. Additionally, irrigation and fertilization management (fertigation) under high tunnels tend to be more efficient than open-field systems, as the frequency of application is increased with a lower volume per application. A higher efficiency of fertigation could alter plant yield responses, especially under traditional planting-density systems. Hence, this study aimed to identify the effect of high planting density on high tunnel tomatoes and their nutrient status on the Eastern Shore of Virginia. The experiment was established on a completely randomized block design with four replications, with 20 ft (6.09 m) experimental plots. We evaluated the combination of two in-row distances and single and double planting rows, with treatments consisting of 2 ft of in-row distance in a single row (4356 plants/acre—current open-field recommendation), 1.5 ft (0.45 m) of in-row distance in a single row (5808 plants/acre [14,520 plants/ha]), 2 ft of in-row distance in a double row (8712 plants/acre [21,780 plants/ha]), and 1.5 ft of in-row distance in a double row (11,616 plants/acre [29,040 plants/ha]). Summer-grown tomatoes produced on the Eastern Shore of Virginia under high tunnel conditions should be planted with 2 ft of in-row spacing and with a single row of plants per planting bed. Increasing the plant density or modifying the current recommended plant distribution could result in yield losses per plant between 32% and 46% and substantial increases in production costs compared with the traditional planting density. Throughout all treatments, tomato plants did not show deficient nutrient status. We hypothesized that irrigation water and pollination were the limiting factors that promoted a decrease in yield per plant for the high-density treatments.

Using High Tunnels to Enhance Organic Vegetable Production in Florida: an Overview

Cost-effective high tunnel systems as a protected production tool hold great potential for offering multifaceted benefits to vegetable growers in Florida beyond season extension. The adoption of high tunnels in the U.S. has been largely fueled by the NRCS High Tunnel System Initiative. Various high tunnel structures may be adapted to the Florida environment for growing high-value vegetable crops. In particular, high tunnels can help improve crop yield and quality in organic vegetable production. This article provides an overview of high tunnel structures and environment, growth of high tunnel production and the organic produce sector, major advantages of using high tunnels to enhance organic vegetable production, and challenges of high tunnel management in Florida. Some online resources for high tunnel vegetable production are provided, and future research needs are also pointed out for improving the long-term environmental and economic sustainability of high tunnel production systems.

The Cost of High Tunnel and Caterpillar Tunnel Establishment for Vegetable Production

Due to increasing marketing and production risks in specialty crop production, a shift toward more protected culture systems such as a high tunnel production system is crucial to keep specialty crop farms profitable and sustainable in the United States. In this publication, we analyzed the cost of constructing high tunnels and caterpillar tunnels in Florida and examined the major contributors to their establishment costs. The findings are intended to assist farmers in deciding whether or not to add high tunnel or caterpillar tunnel systems to their farming operations.

High tunnel production for high yields: options for established and annual asparagus

High tunnel production for high yields: options for established and annual asparagus

Managing Southern Root-knot Nematode in Kentucky High Tunnels Using Grafted Tomato

Infection by root-knot nematode (Meloidogyne spp.; RKN) leads to root galling and reduces the host plant’s ability to take up water and nutrients. Protected cropping systems, such as high tunnels, create conducive environments for RKN through increased soil temperatures and more intensive crop production. In Kentucky, high tunnel production has increased in the past 10 years, with tomato being the most cultivated high tunnel crop. This has contributed to a lack of rotation and increased pressure from RKN. Tomato grafting with RKN-resistant rootstock is a nonchemical management strategy that has shown promise in other regions of the United States. The primary objective of this 2-year, two-site study (Knox and Boyle Counties) was to determine whether using grafted resistant rootstock could be a viable management strategy in high tunnels naturally infested with Meloidogyne incognita. The rootstocks included ‘Arnold’, ‘Maxifort’, ‘Shin Cheong Gang’, and ‘Estamino’. ‘Primo Red’ and ‘Cherokee Purple’ were the scions and nongrafted controls in Knox and Boyle Counties, respectively. In 2020 and 2021 in Knox County, three of the four grafted treatments produced at least 38% higher yield than the nongrafted control. Grafted treatments had at least 44% fewer RKN eggs/g of dry root compared with the nongrafted control in both years. In 2021 and 2022 in Boyle County, tomato yield was at least five times greater in all four of the grafted treatments compared with the nongrafted control. In 2021, the nongrafted control had three times more RKN eggs/g dried root compared with three of the four grafted treatments. In 2022 in Boyle County, the nongrafted control had four times more RKN eggs/g of dried root than all grafted treatments. In both years and locations, ‘Arnold’ and ‘Estamino’ treatments had higher yield and lower RKN population densities in soil and roots compared with the nongrafted controls. Utilization of resistant rootstock will help Kentucky growers maintain crop productivity in soils infested with RKN, but should be combined with other management methods for long-term resiliency of the high tunnel system.

Common Tomato High Tunnel Production Diseases in Florida

This new 7-page article provides a concise overview of some influential high-tunnel tomato soilborne and foliar diseases and their cultural management techniques. Written by Zachary D. Eldred, Shufang Tian, Gary E. Vallad, Xin Zhao, Mathews Paret, and Nicholas S. Dufault and published by the UF/IFAS Plant Pathology Department.https://edis.ifas.ufl.edu/pp368

A systematic assessment of how rootstock growth characteristics impact grafted tomato plant biomass, resource partitioning, yield, and fruit mineral composition.

The appropriate selection of rootstock-scion combinations to improve yield and fully realize grafting benefits requires an in-depth understanding of rootstock-scion synergy. Toward this end, we grafted two determinate-type scions [grape tomato ('BHN 1022') and beefsteak tomato ('Skyway')] onto four rootstocks with different characteristics to examine plant growth, yield performance, biomass production, and fruit mineral nutrient composition. The study was conducted during two growing seasons (spring and fall plantings in Florida) under organic production in high tunnels with the non-grafted scions as controls. Rootstocks had previously been designated as either "generative" ('Estamino') or "vegetative" ('DR0141TX') by some commercial suppliers or had not been characterized ['RST-04-106-T' and 'SHIELD RZ F1 (61-802)']. Also, 'Estamino', 'DR0141TX', and 'RST-04-106-T' had been described as more vigorous than 'SHIELD RZ F1 (61-802)'. In both planting seasons (with low levels of soilborne disease pressure), the "vegetative" and "generative" rootstocks increased marketable and total fruit yields for both scions except for the beefsteak tomato grafted with the "vegetative" rootstock in fall planting. Positive effects of 'RST-04-106-T' on fruit yield varied with scions and planting seasons, and were most manifested when grafted with the beefsteak tomato scion in fall planting. 'SHIELD RZ F1 (61-802)' led to similar yields as the non-grafted controls except for grafting with the grape tomato scion in fall planting. For vegetative and fruit biomass, both the "vegetative" and "generative" rootstocks had positive impacts except for the beefsteak tomato in fall planting. For fruit mineral composition, the "vegetative" and "generative" rootstocks, both highly vigorous, consistently elevated fruit P, K, Ca, Zn, and Fe contents on a dry weight basis, whereas the other rootstocks did not. Overall, although the more vigorous rootstocks enhanced tomato plant productivity and fruit minerals, the evidence presented here does not support the suggestion that the so-called "vegetative" and "generative" rootstocks have different impacts on tomato scion yield, biomass production, or fruit mineral contents. More studies with different production systems and environmental conditions as well as contrasting scion genotypes are needed to further categorize the impacts of rootstocks with different vigor and other characteristics on plant biomass production and their implications on fruit yield development.

Strawberry Cultivar Evaluation for Fall-planted High Tunnel System

Locally produced strawberries (Fragaria ×ananassa) have outstanding market potential. But strawberry production has been decreasing in the north-central United States, partly because of high production risks associated with the traditional matted-row system. The annual plasticulture system attracts attention but its low yield limits the wide adoption of the production system in the north-central United States. High tunnels are widely used to extend strawberry seasons worldwide, but the system was not fully explored in the United States. Although the benefits of growing strawberries in high tunnels were recognized, information on suitable strawberry cultivars specific for the fall-planted high tunnel production system is limited. A wide range of short-day and day-neutral strawberry cultivars, including recently released cultivars, were evaluated in the fall-planted annual plasticulture high tunnel systems for three seasons. Averaged among cultivars, the marketable yields were 1.96, 1.35, and 2.27 lb/plant for 2015–16, 2019–20, and 2020–21 seasons, respectively. The combined use of high tunnels and floating rowcovers created favorable microclimate conditions that led to high yields. Florida Radiance, San Andreas, Chandler, and Rocco were the top-yielding cultivars. Besides Chandler, the other top-yielding cultivars entered peak harvest in the second half of April. Harvests ended at the end of May or early June. All cultivars reached the US Department of Agriculture standard for total soluble solids in all three seasons, although Camino Real, FL Radiance, and Sweet Sensation consistently had relatively lower sugar content. Considering a warm-season crop could grow in high tunnels before or after strawberry, a diversified cropping system involving strawberry and other vegetables is highly valuable for high tunnel production systems in the north-central United States. This study did not compare cultivars’ resistance to diseases, but it should be a critical factor in selecting cultivars. Future studies are also warranted to evaluate the effects of incorporating soil treatments and cover cropping for suppressing diseases in the soil-based high tunnel system. Sustainable management strategies to control two-spotted spider mites (Tetranychus urticae) are also crucial in successfully using the system in the north-central United States.

Effect of High-tunnel Production Systems on the Preharvest Losses and Harvest Quality of ‘BHN 589’ and ‘Cherokee Purple’ Tomatoes

The objective of this study was to investigate the effect of high-tunnel production on preharvest losses and harvest quality of two tomato (Solanum lycopersicum) cultivars. Our results indicate that using high tunnels for tomato production can reduce the preharvest food losses for this crop compared with open-field production, as indicated by increased productivity and percent marketability during the span of three production seasons. The tomato harvest quality did not differ in terms of physical attributes. However, open-field–grown tomatoes demonstrated a significantly greater antioxidant capacity when compared with the high-tunnel–grown tomatoes.

Indoor Vegetable Production: An Alternative Approach to Increasing Cultivation.

As the world's population is increasing exponentially, human diets have changed to less healthy foods resulting in detrimental health complications. Increasing vegetable intake by both rural and urban dwellers can help address this issue. However, these communities often face the challenge of limited vegetable supply and accessibility. More so, open field vegetable production cannot supply all the vegetable needs because biotic and abiotic stress factors often hinder production. Alternative approaches such as vegetable production in greenhouses, indoor farms, high tunnels, and screenhouses can help fill the gap in the supply chain. These alternative production methods provide opportunities to use less resources such as land space, pesticide, and water. They also make possible the control of production factors such as temperature, relative humidity, and carbon dioxide, as well as extension of the growing season. Some of these production systems also make the supply and distribution of nutrients to crops easier and more uniform to enhance crop growth and yield. This paper reviews these alternative vegetable production approaches which include hydroponics, aeroponics, aquaponics and soilless mixes to reveal the need for exploring them further to increase crop production. The paper also discusses facilities used, plant growth factors, current challenges including energy costs and prospects.

Economic Analysis of Grafted Organic Tomato Production in High Tunnels

With the phase-out of methyl bromide because of its impact on ozone depletion and the shift to a more protected culture system in organic vegetable production, grafting practice has gained greater attention in the United States because it may be considered a viable disease control method in organic vegetable production. However, there is a lack of information on the economic feasibility of using grafting in organic tomato (Solanum lycopersicum) production in a protected culture system such as a high-tunnel system. Using 2-year on-station trial data collected in Citra, FL, we examined the effect of using grafting on the economic returns of organic tomato production in high tunnels. Our analysis suggests that grafting tends to increase the marketable yield of organic tomato production in high tunnels. However, the enhanced yield does not necessarily increase the net return, depending on market conditions and the relative performance of grafted transplants. In addition, our results indicate that the net return of grafted production is highly sensitive to the tomato selling price. Obtaining a price premium is essential for increasing the profitability of grafted organic tomato production in high tunnels.

Effect of Rootstock on ‘Tasti-Lee’ Tomato Yield and Fruit Quality in a High Tunnel Production System

Grafting tomatoes with vigorous rootstocks can be used to increase yield in high tunnels without significant soilborne disease pressure. However, evidence suggests that grafting with high-yielding rootstocks could compromise the accumulation of primary and secondary metabolites. ‘Tasti Lee’ is a hybrid tomato that is bred to have a superior fresh-eating quality and higher lycopene content. The objective of this experiment was to investigate the yield and fruit quality impacts of grafting ‘Tasti Lee’ with rootstocks with ranging vigor and typical yield performance in high tunnels. Nongrafted ‘Tasti-Lee’ and ‘Tasti-Lee’ scion grafted onto ‘Maxifort’, ‘DRO141TX’, ‘Fortamino’, ‘Estamino’, and ‘RST-04-106-T’ rootstocks were trialed in a high tunnel in Kansas for three consecutive growing seasons (2018–20). The trials were arranged in a randomized complete block design with four replications. Total yield, marketable yield, average fruit size, and distribution of fruit size classes were assessed. Red ripe tomato fruit were harvested to determine the soluble solids content, titratable acidity, lycopene content, vitamin C content, antioxidant capacity, and fruit firmness. ‘Maxifort’, ‘DRO141TX’, ‘Estamino’, and ‘Fortamino’ significantly increased marketable yield (kg/plant) by 31.5% to 47.0% more than nongrafted plants. In contrast, ‘RST-04-106-T’ did not lend any significant yield benefit. Regardless of the rootstock, grafting increased the marketable average fruit weight by 20 g. Grafting did not have significant effects on any of the fruit quality attributes assessed. However, the soluble solids content of fruit from plants grafted to ‘RST-04-106-T’ was 10% higher (P < 0.05) than that grafted to ‘Maxifort’, indicating that rootstock genotype can influence this quality trait. Our findings suggest that growers can graft the tomato ‘Tasti-Lee’ with select vigorous rootstocks to increase marketable yield without sacrificing fruit quality for high tunnel production.