Impact of Shade and Fogging on High Tunnel Production and Mineral Content of Organically Grown Lettuce, Basil, and Arugula in Georgia

This study evaluated the impact of shade cloth and fogging systems on the microclimate at the plant canopy level and yield of basil (Oscimum basilicum L.), arugula (Eruca vesicaria subsp. Sativa L.), and lettuce (Lactuca sativa L.) planted in mid-September and early October in high tunnels. Fogging systems were installed at canopy level in plots within shaded (30%) and non-shaded high tunnels. Average air temperatures in the shaded high tunnels were 0.9 °C lower than non-shaded high tunnels during the day. Shade cloth significantly reduced soil temperatures during the day and night periods by 1.5 °C and 1.3 °C, respectively, compared to non-shaded treatments. Fogging systems did not have an impact on air temperature, soil temperature, or relative humidity, but did increase canopy leaf wetness. Shade and fogging did not impact the yield of any of the crops grown. Yield was impacted by planting date, with earlier planting result in higher yields of lettuce and basil. Yields for arugula were greater during the second planting date than the first. Planting date and shade cloth interacted to affect the concentrations of macronutrients.

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High Tunnel Coverings Alter Crop Productivity and Microclimate of Tomato and Lettuce

HortScience ◽

10.21273/hortsci16208-21 ◽

2022 ◽

Vol 57 (2) ◽

pp. 265-272

Author(s):

Kelly M. Gude ◽

Eleni D. Pliakoni ◽

Brianna Cunningham ◽

Kanwal Ayub ◽

Qing Kang ◽

...

Keyword(s):

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Crop Productivity ◽

Full Spectrum ◽

High Tunnel ◽

High Tunnels ◽

Soil Temperatures ◽

Subsequent Crop ◽

Leaf Lettuce ◽

The Impact

The implementation of high tunnels has shown to increase marketability and/or yield of tomato (Solanum lycopersicum) and lettuce (Lactuca sativa) crops compared with open-field systems. These structures provide the opportunity to alter light intensity and spectral quality by using specific polyethylene (poly) films and/or shadecloth, which may affect microclimate and subsequent crop productivity. However, little is known about how specific high tunnel coverings affect these parameters. The overall goal of this study was to evaluate the impact of various high tunnel coverings on the microclimate and crop productivity of tomato and lettuce. The coverings included standard, ultraviolet (UV)-stabilized poly film (standard); diffuse poly (diffuse); full-spectrum clear poly (clear); UV-A/B blocking poly (block); standard + 55% shadecloth (shade); and removal of standard poly 2 weeks before initial harvest to simulate a movable tunnel (movable). Microclimate parameters that were observed included canopy and soil temperatures, canopy growing degree-days (GDD), and photosynthetic active radiation (PAR), and crop productivity included yield and net photosynthetic rate. Hybrid red ‘BHN 589’ tomatoes were grown during the summer, and red ‘New Red Fire’ and green ‘Two Star’ leaf lettuce were grown in both spring and fall in 2017 and 2018. Increased temperature, GDD, and PAR were observed during the spring and summer compared with the fall. The soil temperatures during the summer increased more under the clear covering compared with the others. For tomato, the shade produced lower total fruit yield and net photosynthetic rate (Pn) compared with the other treatments, which were similar (P < 0.001 and <0.001, respectively). The greatest yield was 7.39 kg/plant, which was produced under the clear covering. For red leaf lettuce grown in the spring, the plants under the clear, standard, and diffuse coverings had significantly greater yield than the movable and shade coverings (P < 0.001). The coverings had less effect on the yield during the fall lettuce trials, which may have been attributed to the decrease in PAR and environmental temperatures. The findings of this study suggest that high tunnel coverings affect both microclimate and yield of lettuce and tomato.

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Yield of Leafy Greens in High Tunnel Winter Production in the Northwest United States

HortScience ◽

10.21273/hortsci.48.2.183 ◽

2013 ◽

Vol 48 (2) ◽

pp. 183-188 ◽

Cited By ~ 8

Author(s):

Kristy Borrelli ◽

Richard T. Koenig ◽

Brad M. Jaeckel ◽

Carol A. Miles

Keyword(s):

Spinacia Oleracea ◽

Planting Date ◽

Temperate Climate ◽

High Tunnel ◽

Leafy Greens ◽

Air Temperatures ◽

Cropping Season ◽

High Tunnels ◽

Season Extension ◽

Cold Tolerant

Season extension structures like high tunnels make it possible to produce cold-tolerant crops during winter months for both a longer cropping season and a winter market season. The effects of location and planting date on the fresh yield of several cultivars of Asian greens (Brassica rapa L.), lettuce (Lactuca sativa L.), and spinach (Spinacia oleracea L.) were examined at Moscow, ID/Pullman, WA, and Vancouver, WA, a cold temperate climate and a mild marine climate, respectively. In Winter 2005–06, 20 cultivars were evaluated and in Winter 2006–07 a subset of 12 cultivars were evaluated. Location impacted yield, and higher yields overall were attained at Vancouver than at Moscow/Pullman, likely as a result of more consistent, warmer soil and air temperatures as well as increasing irradiance in February and March at Vancouver. Asian green cultivars had the highest overall yield resulting from faster growth compared with spinach and lettuce cultivars at both locations. Although most lettuce cultivars grew throughout the winter, further research is needed to identify the most suitable cultivars, seeding dates, and planting densities to optimize winter production of this crop and for Asian greens and spinach. Planting date influenced yields with the highest yields obtained for the third planting date for all trials except at Moscow/Pullman in the second year. Overall, this research suggests that it is possible to grow many cold-tolerant cultivars of Asian greens, spinach, and lettuce in a high tunnel during the winter months in both mild and cold temperate northern climates.

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Season, sowing date, and row cover influences the production of cool season vegetables in movable high tunnels

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0150 ◽

2020 ◽

Vol 100 (5) ◽

pp. 528-536

Author(s):

David A. Baumbauer ◽

Macdonald H. Burgess

Keyword(s):

Sowing Date ◽

Fresh Weight ◽

Cool Season ◽

High Tunnel ◽

Leafy Greens ◽

Air Temperatures ◽

Seeding Date ◽

Northern Latitudes ◽

Growing Degree Hours ◽

High Tunnels

Moveable high tunnels offer the possibility of increasing the number of crops harvested from a given piece of ground in northern latitudes where there is a short growing season. In an effort to expand crop scheduling options, three leafy greens and three root vegetables were grown in the spring in a movable high tunnel, and in the fall were sown outside and the tunnel was moved over the crops in late September. The effects of seeding date and addition of row cover were further explored on fresh weight and days to harvest. Using row cover within the high tunnel increased growing degree hours (GDH) by an average of 29% in the spring and 17% in the fall over a high tunnel without row cover. Soil degree hours (SDH) in the high tunnel with row cover increased an average of 9% in the spring and 12% in the fall over the high tunnel without row cover. The addition of row cover increased yield of leafy greens and turnip by an average of 35% in spring 2018 when the outside air temperature was considerably below average. Early-seeded fall leafy greens out-yielded late-seeded by 52% due to the ability to make a second harvest. Using row cover within the high tunnel increased GDH and SDH during both spring and fall seasons and increased the yield of cool season vegetables when outside air temperatures were considerably below average.

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Soil Solarization in High Tunnels in the Semiarid Southwestern United States

HortScience ◽

10.21273/hortsci.49.9.1165 ◽

2014 ◽

Vol 49 (9) ◽

pp. 1165-1170 ◽

Cited By ~ 2

Author(s):

Kristen Hanson ◽

Tilak Mahato ◽

Ursula K. Schuch

Keyword(s):

United States ◽

Soil Surface ◽

Soil Solarization ◽

Daily Maximum ◽

Base Temperature ◽

Southwestern United States ◽

High Tunnel ◽

Adverse Weather ◽

High Tunnels ◽

Soil Temperatures

High tunnels are unheated structures covered with polyethylene (PE) glazing to protect high-value crops from adverse weather. The objective of this study was to raise soil temperatures to determine the efficacy of soil solarization using clear mulch on the soil surface and glazing or no glazing on a high tunnel during the hottest months of the year in the semiarid southwestern United States. Solarization trials were conducted in May and June 2013 in two high tunnels in southern Arizona. Highest soil temperatures were reached with the combination of a high tunnel covered with glazing and the soil covered with PE mulch. Average daily soil temperatures were 48 and 47 °C and average degree hours (DH) per day (base temperature 45 °C) were over 14 at soil depths of 5 and 15 cm. The average daily maximum soil temperature at 5- and 15-cm depth was 63.4 and 52 °C, respectively. The second highest soil temperatures were reached when the soil was covered with PE mulch without high tunnel glazing, which resulted per day in 5.2 DH above 45 °C at 5 cm and less than one DH at 15-cm depth. Glazing on the high tunnel without covering the soil surface raised soil temperatures only at the 5-cm depth above 45 °C, but not further down. High tunnel producers in the low desert areas in the southwestern United States can complete solarization in less than 1 week, depending on the organism to be controlled, when the soil is fallow during the summer months with glazing on the high tunnel and on the soil surface.

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High Tunnel and Field System Comparison for Spring Organic Lettuce Production in Georgia

HortScience ◽

10.21273/hortsci12284-17 ◽

2017 ◽

Vol 52 (11) ◽

pp. 1518-1524 ◽

Cited By ~ 1

Author(s):

Theekshana C. Jayalath ◽

George E. Boyhan ◽

Elizabeth L. Little ◽

Robert I. Tate ◽

Suzanne O’Connell

Keyword(s):

Weather Conditions ◽

Romaine Lettuce ◽

Planting Dates ◽

High Tunnel ◽

Light Levels ◽

Air Temperatures ◽

High Tunnels ◽

Average Relative Humidity ◽

Disease Pressure ◽

Tunnel System

High tunnels may help mitigate unfavorable climate and weather on lettuce (Lactuca sativa L.) production leading to greater yields and quality, yet information for using these systems in the Southeast region is lacking. This study evaluated the effect of high tunnels and three planting dates (PDs) (early March, late-March, and mid-April) on spring organic lettuce production. A 25% to 36% increase in marketable fresh weight for butterhead and romaine lettuce, respectively, was observed under high tunnels compared with the field in 2016, but there was no difference among the two growing systems in 2015. High tunnel lettuce was harvested ≈2 to 7 days earlier than in the field in 2015 and 2016, respectively. Pest and disease pressure (e.g., Sclerotinia sclerotiorum) as well as the incidence of physiological disorders (i.e., bolting, tip burn, and undersized heads) were similar between the two systems indicating that our high tunnel system did not provide a benefit for these issues. High tunnel air temperatures were ≈3 to 5 °C greater on the coldest mornings and only 1 °C greater on the warmest days compared with the field. Average relative humidity (RH), leaf wetness, and light levels were all lower under the high tunnels. Our results indicate that high tunnels can help increase the production of spring organic lettuce in Georgia, but that the advantage may depend on yearly weather conditions.

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Effect of High Tunnel Coverings on Antioxidants of Breaker and Light Red Tomatoes at Harvest and during Ripening

Agronomy ◽

10.3390/agronomy10111639 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1639

Author(s):

Kelly M. Gude ◽

Channa B. Rajashekar ◽

Brianna Cunningham ◽

Qing Kang ◽

Weiqun Wang ◽

...

Keyword(s):

Ascorbic Acid ◽

Antioxidant Capacity ◽

Phenolic Compound ◽

Stage Versus ◽

High Tunnel ◽

Shade Cloth ◽

Acid Accumulation ◽

Harvest Maturity ◽

The Impact ◽

Β Carotene

(1) Background: We assessed the impact of high tunnel coverings and harvest maturity (breaker and light red) on antioxidant capacity, ascorbic acid (AsA), lycopene, β–carotene, and phenolic compound (flavonoid and phenolic acid) accumulation in tomatoes (Solanum lycopersicum) at harvest and postharvest. (2) Methods: The two-year study in Olathe, KS, included six different coverings: a standard polyethylene (standard poly), diffuse poly (diffuse), clear poly (clear), UV-A/UV-B blocking poly (block), 55% shade cloth + standard poly (shade), and removal of standard poly two weeks prior to harvest (movable). (3) Results: Antioxidant capacity increased in fruit grown under the clear covering, compared to the shade covering (p < 0.05); similarly, AsA accumulation increased under the standard and clear coverings, relative to the movable and shade coverings (p < 0.001). Postharvest, at the point of consumption (POC), rutin increased in fruit harvested at light red stage versus breaker stage (p < 0.001), and chlorogenic acid increased in light red harvested fruit by 60% under movable, 55% under shade, and 43% under block covering than breaker harvested fruit (p < 0.01). (4) Conclusions: Based on these results, we conclude that both high tunnel covering and postharvest maturation alter antioxidant capacity, AsA, lycopene, and phenolic compound accumulation profiles by the POC.

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Effect of Light Characteristics on the Sensory Properties of Red Lettuce (Lactuca sativa)

Foods ◽

10.3390/foods10112660 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2660

Author(s):

Kelly Gude ◽

Martin Talavera ◽

Audra M. Sasse ◽

Cary L. Rivard ◽

Eleni Pliakoni

Keyword(s):

Open Field ◽

Ultra Violet ◽

Visual Quality ◽

Color Intensity ◽

Shade Cloth ◽

High Tunnels ◽

Green Production ◽

Soil Temperatures ◽

Leaf Lettuce ◽

Effect Of Light

Leafy green production in high tunnels (HTs) results in increased yields, improved visual quality, and extended production with polyethylene (poly) film and/or shade cloth coverings. However, altering visible and ultra-violet light with HT coverings may reduce phytochemicals, thus influencing plant pigmentation and taste. The objective of this study was to examine various HT coverings on the sensory perceptions, soil temperature, color, and anthocyanin accumulation of red leaf lettuce. The coverings included standard poly, standard poly with removal two weeks prior to harvest (movable), diffuse poly, clear poly, UV-A/B blocking poly (block), standard poly with 55% shade cloth, and the open field. A highly trained descriptive panel evaluated the samples using a scale from 0 (none) to 15 (extremely high) and determined a list of 20 sensory attributes. The color intensity attribute had the most differentiation between coverings, and the open field was higher (i.e., darker) than the others at 7.5 (p < 0.0001), followed by clear and movable coverings at 6.8, and the shade covering scored a 2. Strong relationships existed between both colorimetric (hue°) and anthocyanin analysis to panelist-based scores (R2 = 0.847 and 0.640, respectively). The initial crispness was similar for movable, standard, diffuse, and block coverings at 5.3 on average, which was higher than the open field at 4 (p < 0.01). The open field lettuce grew under cooler soil temperatures, which may have slowed down maturation and resulted in softer tissue. Based on this study, HT growers can implement specific coverings to cater to markets that value visual quality.

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Ornamental Kale as a Cut Flower under High Tunnels in the Southeastern United States

HortTechnology ◽

10.21273/horttech04100-18 ◽

2018 ◽

Vol 28 (6) ◽

pp. 855-862

Author(s):

Suzanne O’Connell

Keyword(s):

United States ◽

Southeastern United States ◽

Stem Length ◽

Cut Flower ◽

Planting Dates ◽

High Tunnel ◽

Color Changes ◽

Air Temperatures ◽

High Tunnels ◽

Ornamental Kale

The potential to expand the production of ornamental kale (Brassica oleracea var. acephala) grown as a specialty cut flower in the southeastern United States appears promising, especially for the winter holidays. This 2-year replicated study investigated the effects of two fall plantings and three cultivars on ornamental kale yields grown under organic high tunnels. In addition to the production study, informal interviews of local florists were conducted. The earlier planting dates resulted in longer stem lengths (≥5 cm) and fewer days to harvest (≥5 days) across both seasons. Commercial stem length goals were not achieved (≥60 cm) but local florists did not appear to have the same standards (≥31 cm). The cultivars Crane Bicolor and Lucir White had longer stems and larger heads than Crane Red. Our high tunnel system provided favorable air temperatures for vegetative growth from late September through early November indicating an earlier planting date may be possible. Commonly accepted nighttime temperatures required to induce color changes occurred in early to mid-November during our study period.

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Effect of Tomato Rootstock on Hybrid and Heirloom Tomato Performance in a Midwest High Tunnel Production System

HortScience ◽

10.21273/hortsci13874-19 ◽

2019 ◽

Vol 54 (5) ◽

pp. 840-845

Author(s):

Kristine M. Lang ◽

Ajay Nair

Keyword(s):

Production System ◽

Chlorophyll Concentration ◽

Research Station ◽

Continuous Cropping ◽

Tomato Production ◽

High Tunnel ◽

Leaf Chlorophyll ◽

High Tunnels ◽

The Impact ◽

Leaf Chlorophyll Concentration

High tunnels allow vegetable growers to extend the growing season, increase crop production, and improve produce quality. Tomatoes (Solanum lycopersicum L.) are the most widely grown crops in high tunnels; however, tomato production in high tunnels can be challenging. Continuous cropping in high tunnels can increase soil-borne disease pressure and can lead to soil salinity or nutrient depletion issues. Based on preliminary research, we hypothesized that use of the rootstock ‘RST-04-106-T’ would increase yield and quality of heirloom and hybrid tomato scions compared with nongrafted plants. To test this hypothesis, our research objectives were to assess marketable yields, fruit quality and nutritional value, and plant growth of grafted and nongrafted hybrid and heirloom tomatoes in a high tunnel production system. Grafted and nongrafted ‘Cherokee Purple’ (heirloom) and ‘Mountain Fresh Plus’ (hybrid) tomatoes were grown in the same high tunnel for two seasons (7 May–20 Oct. 2015 and 29 April–7 Oct. 2016) at the Horticulture Research Station in Ames, IA. Grafted plants produced significantly more marketable fruit, although marketable and total fruit weight did not increase significantly. Individual fruit size was unaffected by grafting. Across cultivars, mean soluble solids content (SSC) in fruit was 0.3 °Brix lower in grafted plants as compared with the nongrafted control. Grafting did not affect lycopene content of fruit. Grafting increased stem diameter by an average of 0.8 mm, but overall plant biomass was unaffected. The effect of grafting on leaf chlorophyll concentration (SPAD readings) was mixed. In addition, grafting increased leaf chlorophyll concentration in ‘Cherokee Purple’ but decreased it in ‘Mountain Fresh Plus’ plants. Grafting is a valuable tool in tomato production, but the impact of ‘RST-04-106-T’ rootstock use appears to be specific to certain soil types with high incidence of bacterial wilt.

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Microenvironmental Variations within the High Tunnel

HortScience ◽

10.21273/hortsci.44.2.235 ◽

2009 ◽

Vol 44 (2) ◽

pp. 235-238 ◽

Cited By ~ 9

Author(s):

Hans Christian Wien

Keyword(s):

Spatial Variation ◽

Growing Season ◽

Ambient Air ◽

Cut Flowers ◽

High Tunnel ◽

Perennial Crops ◽

Freezing Soil ◽

Horticultural Crops ◽

Air Temperatures ◽

Soil Temperatures

Simple unheated greenhouses covered with clear polyethylene, also known as high tunnels, in which plants are typically grown in the ground have become popular for extending the growing season for high-value horticultural crops. Although they are used principally to produce annual crops such as vegetables and cut flowers, increasing interest has focused on their use for perennial crops such as raspberries, blackberries, and ornamentals. Studies of temperature variation within the tunnel during the growing season have emphasized the rapid rise in air day temperature above ambient during the day and an equally rapid decrease at night. Spatial variation in temperature within the tunnel were much less marked, however, with air temperatures at the edge of a 10-m wide tunnel only ≈2 °C lower than in the center. For perennial crops, tunnel conditions during the off-season are also an important factor. In winter, air temperatures in the tunnel during sunny days rose above freezing even when ambient air temperatures stayed below freezing. Soil temperatures during the day and night fluctuated much less both inside and outside the tunnel and were significantly higher in the tunnel. Studies with nursery plants overwintered in similar structures indicate that spatial variation is again dwarfed by the overall air temperature fluctuation in these structures.

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