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In temperate climates, aquaponic producers must use artificial lighting; however, purchasing light-emitting diode (LED) grow lights can be cost-prohibitive. Two aquaponic trials evaluated low-cost LED lighting for the growth of bibb lettuce (Lactuca sativa var. capitata). In trial 1, seven low-cost LED lights were screened and compared with a high-end LED grow light. The three best-performing lights in terms of total plant biomass produced (grams) and total plant biomass per unit of electricity (grams per square meter per kilowatt-hour) were more intensively evaluated in trial 2. These lights included Spider Farmer SF-2000 [SPI ($300)], Fluence RAZRx [FLU ($364)], Designers Fountain 6-Light 5000 K LED High Bay Light [DES ($100)], and the control NeoSol DS [NEO ($1400)]. After 17 days, lettuce grown under NEO achieved higher (P ≤ 0.05) total biomass (939 g) than DES (812 g). There were no differences (P > 0.05) in the average individual plant weights in any treatment. Plant production efficiency (grams per square meter per kilowatt-hour) was higher in DES than NEO (P ≤ 0.05) but was not different from SPI and FLU (P > 0.05). Results indicate that low-cost LEDs are a viable option for producers looking to reduce investment costs while maintaining adequate plant growth. To further describe potential cost savings for producers, a partial budget analysis evaluated the net change in profits and benefit/cost ratio (BCR) of the experimental lights. All showed improved economic results compared with the control (NEO). These studies indicate that low-cost LED lights can support similar plant growth, at higher energy efficiencies, with better economic viability than more expensive grow lights.

Farmers in the high desert are challenged by a short growing season and slow crop establishment of warm-season vegetables. Yet an increasing demand for local produce in nearby urban areas presents an opportunity to diversify farms while adapting to climate uncertainty. Vegetable rootstocks can confer advantages under biotic and abiotic stress conditions, but information on which and how melon rootstocks can improve management does not exist for high desert and short-season regions. Commercial, squash-hybrid rootstocks (i.e., Cucurbita maxima × C. moschata) were grafted with a common scion (Cucumis melo cv. Sarah’s choice). Nine rootstocks in 2021 and four selected rootstocks in 2022 were evaluated in four field trials (two per year) in northern Nevada at two distinct locations. Melon grafting did not consistently increase crop performance in the high desert, and it was influenced by location and year. Throughout the initial half of the harvesting period, grafted plants tended to produce more melons, irrespective of location or year, offering a potential appeal for melon growers operating in shorter growing seasons. However, a slight reduction in fruit quality (i.e., °Brix) was observed in some grafted plants compared with the ungrafted control. The benefits of grafting melons onto squash hybrids in high desert conditions remain uncertain and may depend on microenvironment and farming practices that affect crop establishment, such as mulching effects on soil temperature.

We investigated the growth dynamics of hydroponic lettuce (Lactuca sativa) driven by the influence that potassium (K⁺) has on crop growth. This study aimed to determine whether increased K⁺ concentrations under different daily light integrals (DLIs) in a hydroponic system will boost growth of greenhouse lettuce. This study was conducted within a controlled glass greenhouse environment with varying DLIs achieved by integrating an adaptive lighting control system over a 16-hour photoperiod. We used three K⁺ treatments of 200, 400, or 600 mg⋅L⁻¹ K⁺ and six DLI lighting treatments of 11.1, 12.9, 14.6, 15.9, 16.9, and 17 mol⋅m⁻²⋅d⁻¹. We found that increasing K⁺ did not increase shoot dry weight, leaf area, or specific leaf area with increasing DLIs. Although K⁺ and DLI had an interacting effect on the root dry weight fraction, leaf chlorophyll content, and quantum yield of photosystem II, the K⁺ treatments did not increase or decrease with increasing DLIs. The influencing factor was DLI, which led to increases in shoot dry weight and leaf area, whereas a decrease in specific leaf area was observed with increasing DLIs. Ultimately, adding supplemental concentrations of K⁺ did not enhance lettuce growth, nor did these effects show any increase with increasing DLIs.

Perennial ornamental grasses are often recommended for rain gardens, but few data support their use. We conducted two experiments to evaluate the ability of ornamental grass cultivars to grow while subjected to cyclical flooding, submergence, and drought typical of rain gardens. Our objectives were to determine the effects of cyclical flood and drought (Expt. 1) and submergence depth and duration (Expt. 2) on grass growth and survival. Seven cultivars were evaluated during greenhouse trials, including Pixie Fountain tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.], Northwind switchgrass (Panicum virgatum L.), Red October big bluestem (Andropogon gerardii Vitman), Purpurascens Chinese silvergrass (Miscanthus sinensis Andersson), Blue Heaven^® little bluestem [Schizachyrium scoparium (Michx.) Nash], Blonde Ambition blue grama grass [Bouteloua gracilis (Kunth) Lag. ex Griffiths], and Karl Foerster feather reed grass [Calamagrostis ×acutiflora (Schrad.) DC]. During Expt. 1, grasses underwent four cycles of flooding duration (2 days or 7 days) followed by drought (drying to volumetric soil water contents of 0.14 or 0.07 cm³·cm⁻³). During Expt. 2, grasses were cyclically submerged at 15 or 30 cm above the soil surface for 2, 4, or 7 days, followed by floodwater removal and drainage for 2 days before being resubmerged. Cyclical submergence continued until the 7-day submergence treatments completed four cycles. Both experiments were replicated in a full factorial randomized complete block design. Controls were included in both experiments. Plants were measured to determine plant height, shoot count, visual damage rating, shoot dry weight, and root dry weight. Floodwater chemistry and soil reducing conditions were measured during Expt. 2. Chinese silvergrass and switchgrass survived cyclical soil flooding/drought and submergence for 7 days at a depth of 30 cm while maintaining acceptable foliar damage. All grasses survived cyclical flood and drought when the soil volumetric water content was maintained at 14%, suggesting they can withstand periodic soil flooding as long as the water is not too deep. As water depth and duration increased from 4 days to 7 days, little bluestem, blue grama grass, and feather reed grass experienced significant foliar damage. Tufted hair grass and big bluestem experienced significant foliar damage when submerged for 2 days. Our results showed that perennial ornamental grasses can tolerate cyclical flood and drought and periodic submergence, but that plant conditions and survival vary, which can inform strategic plant placement within rain gardens, bioretention basins, and other stormwater management systems.

Storage information regarding ‘Keepsake’ apple fruit is lacking. The objective of this research was to investigate the postharvest characteristics of ‘Keepsake’ apple (Malus ×domestica Borkh.), which is a parent of ‘Honeycrisp’. Apples were obtained from three orchards in Minnesota in 2022 and 2023, assessed for quality, and stored at 0 to 1 °C or 4 to 5 °C in air. Fruit were tested for firmness, soluble solids content (SSC), and titratable acidity (TA) for up to 6 months in storage. At harvest, fruit from different orchards differed in ground color, firmness, SSC, and titratable acidity. The starch pattern index did not differ among the orchards within a year, but it was greater during the 2023 harvest than during the 2022 harvest. Fruit firmness decreased less rapidly at 0 to 1 °C than at 4 to 5 °C. Changes in SSC with storage varied by orchard, storage temperature, and year. In 2022 to 2023, SSC changes were highly variable, remained the same during storage for fruit from one orchard, increased and then decreased for fruit from another orchard, increased after 1 month of storage, and then remained unchanged thereafter for fruit from the third orchard. In 2023 to 2024, SSC was generally unchanged during storage at 0 to 1 °C, and it increased slightly over time during storage at 4 to 5 °C. Titratable acidity decreased during storage, but there was no difference between storage temperatures. These findings demonstrate the difficulty determining when to harvest ‘Keepsake’ fruit because neither starch pattern index nor ground color is a reliable indicator of ripeness. Growers must rely on experience and fruit redness to determine when to harvest this late-season cultivar. To prolong fruit firmness, growers should store ‘Keepsake’ fruit at 0 to 1 °C rather than at 4 to 5 °C.

Continuous application of chemical fertilizers in plant cultivation can lead to the deterioration of the soil environment, resulting in reduced crop yield and quality. Currently, organic fertilizers, such as vermicompost, can partially replace chemical fertilizers and maximize yields while maintaining soil fertility. However, the effects of chemical fertilizers combined with vermicompost on watermelon (Citrullus lanatus) yield and quality are unclear. A field experiment was carried out on the watermelon cultivar Lihua No. 6. Six treatments were applied: no fertilizer (CK, control, 0N–0P–0K), 100% chemical fertilizer [CF, 5.4N–1P–5.4K (256, 47, and 255 kg·ha⁻¹)], 75% chemical fertilizer + 25% organic fertilizer [A1, 5.4N–1P–5.4K (192, 35, and 191 kg·ha⁻¹) + 2250 kg·ha⁻¹ vermicompost], 50% chemical fertilizer + 50% organic fertilizer [A2, 5.4N–1P–5.4K (128, 24, and 127 kg·ha⁻¹) + 4500 kg·ha⁻¹ vermicompost], 25% chemical fertilizer + 75% organic fertilizer [A3, 5.4N–1P–5.4K (64, 12, and 64 kg·ha⁻¹) + 6750 kg·ha⁻¹ vermicompost], and 100% organic fertilizer (A4, 9000 kg·ha⁻¹ vermicompost). Indices related to the growth, yield, and quality of watermelons were determined. Compared with CK, chemical fertilizer alone or in combination with organic fertilizers significantly increased growth parameters (plant height and leaf area) and chlorophyll content. The five fertilizer treatments enhanced the single fruit weight, yield, and biomass. In addition, the yield of reduced chemical fertilizer plus organic fertilizer was comparable to that of watermelons treated with CF. Compared with CF, the fertilizer treatments, especially the 1:1 mixture of chemical and organic fertilizer (A2) group, had elevated fruit-soluble solids and soluble sugar content, and reduced organic acid levels. Therefore, a combination of 50% chemical fertilizer and 50% organic fertilizer can effectively enhance the yield and quality of watermelons. These findings have important implications for guiding the management of watermelon fertilization and development of sustainable agriculture.

The application of seaweed extract and microbial biostimulants has been suggested as a promising approach to overcome yield-limiting factors in organic farming. Yet, information regarding their impact on organic strawberry production is limited. This 2-year field study evaluated the effect of seaweed extract and microbial biostimulants and their synergistic effects on strawberry plant growth, nutrient uptake, fruit yield, and quality under organic production. The biostimulant effects were compared on two strawberry cultivars: Sweet Sensation^® Florida127 and Florida Brilliance. Over two seasons, the combination of seaweed extract plus microbial biostimulants applied biweekly consistently resulted in a significant increase of whole-season marketable and total strawberry fruit yields by 23% and 20% on average, respectively, compared with the no-biostimulant control. Application of either biostimulant alone did not consistently show positive effects on strawberry productivity. Modified strawberry root system architecture, enhanced N uptake, increased number of crowns, and higher soil respiration were observed in the biostimulant combination treatment in contrast to the no-biostimulant control. The biostimulant impact was not influenced by strawberry cultivar, but genotypic difference in yield performance under organic production was observed. ‘Florida Brilliance’ produced significantly higher total fruit number and yield than ‘Florida127’ by 26% and 12%, respectively, in the first season, and by 34% and 11%, respectively, in the second season. Marketable fruit number (by 18%) and yield (by 9%) of ‘Florida Brilliance’ were also higher in the first season, along with greater marketable fruit number (by 31%) in the second season. In addition, ‘Florida Brilliance’ showed significantly higher values of SPAD index, photosynthetic rate (early harvest), and fruit mineral contents based on dry weight (late harvest) than ‘Florida127’ in both seasons. Although the biostimulant treatments exhibited little influence on the fruit quality attributes including soluble solids content (SSC), titratable acidity (TA), SSC/TA, and total anthocyanin content, varietal differences were observed with significantly higher levels of SSC and lower contents of total anthocyanins in ‘Florida 127’ vs. ‘Florida Brilliance’ during each season. The benefits of combined application of seaweed extract and microbial biostimulants demonstrated in this study suggest the need to further elucidate their synergistic functions in promoting nutrient uptake and fruit yield in organic strawberry production systems under different soil and environmental conditions.

This work studied the micropropagation of fegra fig (F. palmata Forssk.) during which we experienced the incidence of shoot-tip necrosis (STN). STN was evident during the shoot elongation stage, which was regenerated on Murashige and Skoog (MS) medium supplemented with 2 mg/L 6-benzylaminopurine. To alleviate SNT, we conducted a series of experiments and supplemented the medium with calcium chloride (40, 80, and 120 mg/L), ascorbic acid (50, 100, and 150 mg/L), silver nitrate (1, 2, and 3 mg/L), and boric acid (9.3, 12.4, and 15.5 mg/L). Results showed that all the treatments controlled STN at varying levels, and supplementation of medium with 3 mg/L silver nitrate reduced the incidence of STN from 80% to 24%. The regenerated shoots were rooted on the same medium with incubation of cultures in the dark for 3 weeks and subsequent 4 weeks of incubation under 16/8-hour light/dark photoperiod. The growth parameters (number of shoots and roots, length of the main shoot and root, fresh and dry weights), photosynthetic pigments (chlorophylls and carotenoids), and relative water content of plantlets were restored with the application of 3 mg/L silver nitrate to the medium. Incubation of cultures initially in the dark followed by 16/8-hour light incubation facilitated axillary shoot elongation. On the basis of our findings, it is recommended to culture the regenerated axillary shoots of fegra fig onto MS medium containing 3% sucrose, 1.5 mg/L activated charcoal, and 3 mg/L silver nitrate to manage STN effectively.

Here we review the 400-year history of hydroponic culture and describe a unique management approach that does not require leaching or discarding solution between harvests. Nutrients are maintained at a low and steady concentration by daily additions of a dilute solution that replaces the transpired water along with the nutrients that were removed in growth each day. A stable pH and a low steady-state concentration of ammonium are maintained through automated additions of a solution of nitric acid and ammonium nitrate. Ample solution volume (at least 20 cm deep) stabilizes nutrient concentrations, reduces root density, and improves uniformity. Gentle aeration at ≈100 mL·min⁻¹·L⁻¹ maintains dissolved oxygen near saturation and increases uniformity throughout the rhizosphere. These practices facilitate a uniform, closed, root zone with rigorous pH control that provides the micromolar nutrient concentrations of N and P that are representative of field soils.