Search Results (155)

Microgreens have gained increasing popularity due to their cooking versatility, ease of cultivation, and high nutritional value. The use of alternative organic substrates, such as vermicompost and insect frass, offers a promising alternative to peat. This study has evaluated the integration of Tenebrio molitor and Hermetia illucens frass, along with vermicompost, in a microgreen production, while assaying several concentrations (25%, 50%, 75%, and 100%) as replacements by weight. After a preliminary assay aimed at determining the optimal frass and vermicompost levels, we assessed the agronomic, nutritional, and microbiological performances of microgreens. The preliminary results revealed phytotoxic effects of T. molitor frass, while the addition of H. illucens frass or vermicompost did not significantly impact microgreen production. In the second experiment, the interaction between plant species and substrate composition significantly influenced the leaf area, plant height, and mineral content. Partial replacement of peat with H. illucens frass or vermicompost enhanced leaf area and plant height, with a notable increase in iron content in the mizuna microgreens grown with H. illucens frass, compared to the control with peat. Additionally, microbiological safety was ensured, and a complete absence of Salmonella spp. and E. coli was observed in the plants, in accordance with European food safety regulations. Full article

Coir is widely used as a soilless substrate yet partially replacing it with walnut shells in coir-based mixes may improve the sustainability of lettuce production and quality. This study evaluated the effect of incorporating walnut shells, with or without biochar, into coir-based substrates on lettuce yield and quality. Lettuce was grown in five substrates: coir (C), three coir–walnut mixes (1:1, 1:0.5, and 1:0.25 v/v), and one coir–walnut–biochar mix (C:W:B, 10:1.5:1 v/v). Increasing the walnut-shell proportion increased the cumulative leaching fraction, likely because of the coarse walnut particles, and reduced head fresh weight. However, shoot dry weight in the 1:0.5 and 1:0.25 mixes was similar to that in coir alone and reduced leaf nitrate content. In contrast, the C:W:B mix maintained head fresh weight (7.1 kg m⁻²) and shoot dry weight comparable to coir, while markedly lowering leaf nitrate concentration from 4130 to below 200 mg NO₃⁻ kg⁻¹ fresh weight. Leaf nitrate content increased linearly with shoot Zn uptake, suggesting a Zn-mediated control of nitrate accumulation. The coir–walnut–biochar mix emerges as a suitable alternative to pure coir, as it maintains lettuce productivity, reduces leaf nitrate accumulation, enhances anthocyanin content, and reflects more favorable physiological conditions by not requiring a strong activation of antioxidant defenses. Full article

Biostimulants boost plant growth, productivity, and nutrient retention, and can be produced from agri-food waste via microbial fermentation. In this study, undersized and unsold kiwifruits were fermented with Lactiplantibacillus plantarum to produce a fermented kiwifruit-based biostimulant (FKB). FKB was applied to soilless tomato plants (cv. Solarino) at two concentrations (50 and 100 mL L⁻¹) at the root level, every two weeks throughout the crop cycle. Fruits were analyzed for technological and chemical parameters, including color, texture, total soluble solids, titratable acidity, sugar/acid ratio, pH, electrical conductivity, total polyphenol content, antioxidant activity, and lycopene concentration. Additionally, metataxonomic analysis characterized the substrate microbial community at the beginning and the end of cultivation. Overall, the results indicate a dose-dependent effect of FKB on fruit quality parameters, with the highest concentration showing the most pronounced effects, specifically for the fruit firmness (8.02 N for FKB at 100 mL L⁻¹ vs. 7.25 N for the Control). Moreover, both tested concentrations were associated with increased antioxidant activity (on average +28%), and lycopene content (on average +57%) compared with the Control fruits. While overall microbial diversity remained largely unchanged, the relative abundance of bacterial taxa associated with nutrient cycling and plant–microbe interactions was modulated by the biostimulant, indicating subtle but potentially functionally relevant shifts in the rhizosphere microbiota. These findings suggest that fermented kiwifruit biomass can serve as an effective biostimulant, improving both fruit quality and the functional structure of the rhizosphere microbial community in soilless tomato cultivation. Full article

In the face of escalating global challenges, including climate change, food insecurity, freshwater scarcity, soil degradation, and rapid urbanization, soilless farming systems, such as hydroponics, aquaponics, and bioponics, have emerged as innovative and sustainable farming solutions. Combined with precision agriculture technologies, these systems enable real-time optimization of inputs through smart sensors, automation, and predictive modeling, significantly reducing resource consumption while improving crop yields. This review provides a unique contribution by integrating and comparing the three major soilless systems within a single framework and by highlighting, for the first time, their potential synergies with precision agriculture. It critically examines soilless cultivation systems and their relationship with precision agriculture, assessing the agronomic, environmental, and economic benefits as well as the main challenges, including high initial costs, high energy consumption, the complexity of managing biological inputs, the lack of standardized protocols, and limited accessibility for small-scale producers. The review highlights the need to integrate renewable energy sources, develop biodegradable substrates, apply life cycle assessment methodologies, and implement adequate training and regulatory frameworks to promote wider adoption and sustainability. Full article

The global production of blueberries (Vaccinium corymbosum L.) has increased rapidly due to rising demand for antioxidant-rich fruits, making this crop increasingly important worldwide. Because blueberries require acidic soils, soilless systems offer a promising alternative by optimizing nutrient availability and reducing soil-related limitations. Among sustainable amendments, biochar (BC) improves water retention, porosity, and microbial activity, while wood distillate (WD), rich in bioactive compounds, can enhance plant resilience and growth. Although often used separately, their combined application may exert synergistic effects on substrate fertility and plant performance. This study investigated the effects of BC and WD, alone and in combination, on the growth, yield, and fruit quality of the ‘Cargo’ blueberry cultivar grown in a soilless system. Two distinct harvests were conducted during the growing season, and statistical analyses were performed independently for each, assessing treatment effects in relation to harvest timing. Moreover, the metabolic activity of the substrate’s microbial community was evaluated to assess the impact of the treatments. Results showed that BC application, particularly at 10%, significantly enhanced plant yield and fruit quality, increasing total phenolic content and antioxidant activity, while WD exhibited variable, dose-dependent effects on growth and biochemical traits, highlighting species-specific responses in soilless blueberry cultivation. Full article

Substrate composition plays a vital role in the soilless cultivation of Helleborus; high-quality substrates can create optimal growth conditions and enhance plant quality. However, knowledge regarding suitable substrates for Helleborus remains limited. The aim of the study was to test the effects of different substrates on growth of potted Helleborus × hybridus seedlings. In total, 12 treatments were formulated by mixing organic components (moss peat, cocopeat, domestic peat) with inorganic particles (perlite, kanuma soil, vermiculite) at a 1:1 ratio, using moss peat moss as the control. The results indicated that substrates of moss peat + vermiculite (1:1) and cocopeat + vermiculite (1:1) significantly promoted plant height, shoot number, leaf number, and root development. The treatment with domestic peat + perlite + kanuma soil + vermiculite (3:1:1:1) yielded the highest soluble protein content, whereas the CK group showed the highest soluble sugar content. A comprehensive evaluation by Principal Component Analysis (PCA) identified moss peat + vermiculite (1:1) as the optimal substrate, followed by coir + vermiculite (1:1). Considering economic costs and environmental protection factors, the cocopeat + vermiculite (1:1) mixture demonstrated superior potential. Collectively, our study clarifies the effects of different substrate compositions and provides new insights for achieving cleaner and more efficient soilless cultivation of Helleborus. Full article

Restrictive regulations on the use of peat and increasing consumption in modern horticulture production have created an irreconcilable contradiction. Wood fibers (WF) produced from forestry residues are considered as a promising peat substitution. However, their poor water- and nutrient-holding capacity limit their application. Here, wood fiber–hydrogel composite (WF-Gel) was developed via a one-pot strategy by grafting poly(acrylic acid-co-acrylamide) (P(AA-co-AM)) onto WF. The structure of the hydrogel network incorporated with WF was confirmed by FTIR spectrophotometry, scanning electron microscopy, X-ray diffractometry, and thermogravimetric analysis. The growing substrate amended with WF-Gel showed higher physical properties, including water-filled porosity (~62.33%) and water-holding capacity (~44.93%) compared with peat incorporated with WF. The pot experiment revealed that WF-Gel significantly increases the chlorophyll content and relative growth rate of choy sum (Brassica rapa var. parachinensis), especially at the initial transplanting stage. Moreover, choy sum grown in a substrate containing WF-Gel showed a significant increase in biomass accumulation. Additionally, nutrient content and irrigation water-use efficiency data indicated that WF-Gel as a growing medium strongly promotes the water and nutrient efficiency of choy sum. Therefore, the incorporation of this hydrogel modification strategy is a promising approach to promote the water- and nutrient-use efficiency of WF as a soilless substrate component. Full article

The soil of the Trifinio region, the tri-national territory between Guatemala, Honduras, and El Salvador, is damaged by the expansion of monoculture, which decreases fertility and causes problems for local farmers. Furthermore, the region also faces issues of erosion and soil contamination. As an alternative to soil cultivation, soilless systems can be adopted, not requiring fertile soil, and significantly increasing yields and resource use efficiency. To encourage soilless technique application in the region, the aim of this study was to compare 18 different substrate mixes to identify the most suitable for the local cultivation of cucumber (Cucumis sativus L.). The substrates were obtained comparing three rates of peat and compost (0%, 20% and 40%, by volume) in factorial combination, with the remaining being either coir or pumice (filling component). Plant growth, flower setting, physiological status (relative chlorophyll content and leaf temperature), and plant production were evaluated. Highest yield was achieved with 20% peat, while compost (20% and 40%) was able to increase fruit length and improve the relative chlorophyll content, but did not affect total production. However, when focusing on environmental sustainability as an important standpoint, a peat-free substrate should be utilized even though the results favored the 20% peat treatment for production. Considering that the differences in production in favor of 20% peat treatment were of limited practical relevance. In regard to the filling components (coir and pumice) yields were unaffected and only minor parameters were changed. Based on the results obtained, a substrate consisting of 60% coir and 40% compost resulted in the best option for the soilless cultivation of cucumber in the Trifinio region, with both materials being sustainable and easily available for local farmers. Full article

The pore structure of cocopeat-based substrates critically influences their hydraulic properties, directly affecting water use efficiency in soilless cultivation systems. Previous macroscopic modeling approaches infer pore structures indirectly from water retention curves and rely on empirical parameterization of pore geometry and connectivity, overlooking microscale features that directly control fluid pathways and permeability. To address this gap, this study employed micro-CT imaging to reconstruct the three-dimensional pore structures of coarse cocopeat and a fine cocopeat–perlite mixture. Nine regions of interest (ROIs), representing three typical pore types in each substrate, were selected for quantitative pore structure analysis and pore-scale saturated flow simulations. Results show that over 90% of pore diameters in both substrates fall within the 0–400 μm range, and variations in cocopeat particle size and perlite addition significantly affect average pore diameter, porosity, fractal dimension, and tortuosity, thereby influencing permeability and local flow distribution. This study provides new insights into the microscale mechanisms governing water movement in cocopeat-based substrates and reveals key structural factors regulating hydraulic behavior in soilless cultivation systems. Full article

Fruit production is a high environmental impact sector, requiring sustainable strategies that reduce greenhouse gas (GHG) emissions, improve resource efficiency, and maintain fruit quality. This study assessed the environmental performance of innovative substrates with biodegradable additives and organic binders in tunnel-grown raspberry production. The functional unit was 1 kg of marketable fruit, and the experiment was conducted in Karwia, Poland. GHG emissions were calculated for eight substrate variants following ISO 14040 and 14041 guidelines. The baseline was coconut fiber, while modified variants included the additions of sunflower husk biochar and/or a wood-industry isolate, representing sustainable strategies in soilless cultivation. Emissions ranged from 0.728 to 1.226 kg CO₂ eq/kg of raspberries, with the control showing the highest values. All modified substrates (produced based on a mixture of biochar and isolate) reduced emissions, with the most efficient variant achieving nearly a 40% decrease. Water use efficiency was decisive, as consumption declined from 2744 m³/ha (control) to 1838 m³/ha in improved variants. Substrate air–water properties proved critical for both environmental and economic outcomes. The findings confirm that substrate modification constitutes an effective, sustainable strategy for raspberry production under high tunnels, supporting climate-smart horticulture and resource-efficient food systems. Full article

Golden thistle (Scolymus hispanicus L.) is a wild edible green of high nutritional value, used in the traditional Mediterranean diet. Nowadays, there is an increasing demand from consumers for golden thistle and concomitantly an increasing interest in integrating it into modern cultivation systems. Soilless culture is a promising cultivation option that can maximize yield and quality of golden thistle. The aim of this study was to examine the combined effect of electrical conductivity (EC) and nitrogen (N) supply level on growth and nutritional quality of golden thistle grown on a substrate in a soilless cropping system. The two experimental factors were examined in a 2-factorial experiment with two EC levels, a low (2.2 dS m⁻¹) and high (2.8 dS m⁻¹), combined with two total-N (NO₃⁻ + NH₄⁺) supply levels, low (13.30 mmol L⁻¹) and high (17.30 mmoL L⁻¹), in the supplied nutrient solution. Root fresh and dry weight (commercial yield) were unaffected by treatments; however, high EC significantly reduced shoot fresh and dry biomass by 21 and 28% compared to low EC. High EC increased K⁺ concentrations in shoots and roots but decreased shoot Ca²⁺ level. Nitrate concentration in the drainage solution and plant tissues was primarily driven by N supply, with high N increasing leaf NO₃⁻ by up to 45% without surpassing the regulatory safety limit. Water productivity did not differ among treatments, but low EC improved agronomic efficiency of K⁺, Ca²⁺, Mg²⁺, and S, while low N enhanced N agronomic efficiency by 44%. Overall, low EC promoted vegetative growth and nutrient use efficiency, while increasing N above 13.3 mmol L⁻¹ offered no yield benefit and raised tissue nitrate levels. For optimal yield and quality, a nutrient solution with low EC and N supply is recommended for the soilless cultivation of golden thistle. Full article

Soilless cultivation has emerged as a sustainable solution for modern agriculture, yet substrate formulation is still often guided by empirical approaches, limiting efficiency and reproducibility. To address this gap, we established a data-driven framework for optimizing substrate composition in garden lettuce (Lactuca sativa L.) cultivation. Using a randomized design, 200 substrate formulations were prepared from peat, vermiculite, and perlite, and their effects on plant growth were evaluated under controlled environmental conditions. Peat content reduced substrate porosity and water-holding capacity, whereas vermiculite increased both properties (linear regression, p < 0.05). Substrate formulations profoundly affected plant biomass, and the peat content was identified as a key predictor. Two rounds of substrate optimization resulted in a significant increase in shoot and root biomass and chlorophyll content, with increases of 57.5% (p = 9.2 × 10⁻⁸), 89.8% (p = 8.24 × 10⁻¹⁰), and 43.3% (p < 2 × 10⁻¹⁶), respectively, compared with the initial trial. Additionally, hyperspectral imaging (HSI) and RGB imaging were employed for growth monitoring. Random forest machine-learning method identified several red-edge indices (NDVI₇₀₅, mNDVI₇₀₅, mSR₇₀₅) as highly responsive predictors of substrate formulations, highlighting the potential of imaging traits as proxies for substrate optimization. This study provides a reproducible pathway for improving soilless substrate formulations, contributing to data-informed substrate design and advancing the practice of precision agriculture. Full article

Standardized pharmaceutical-grade cultivation of Cannabis sativa L. increasingly relies on soilless systems for precision, reproducibility, and regulatory compliance. This review examines the role of inert and semi-inert growing media in indoor cannabis production, focusing on their physical properties, agronomic performance, and sustainability. A systematic literature search was conducted using databases such as Scopus, Web of Science, and Google Scholar, emphasizing peer-reviewed original research, experimental trials, and relevant review articles. Evaluated substrates include rockwool, coconut coir, peat-based blends, perlite, vermiculite, expanded clay, foamed glass, phenolic foam, and biochar. Findings show that substrate selection strongly affects vegetative growth, rooting, and flower yield, while cannabinoid concentrations remain primarily genotype-driven under stable environmental and nutritional conditions. Substrate-specific traits such as aeration, water-holding capacity, and nutrient buffering significantly influence biomass production and resource-use efficiency. Rockwool remains the industry standard due to its uniformity and compatibility with fertigation systems, but renewable alternatives like coconut coir and biochar are gaining traction. This review underscores the importance of substrate selection in cannabis cultivation and identifies research gaps in genotype-specific responses and the development of sustainable growing media. Full article

The transformation of organic by-products derived from waste into value-added resources represents a promising strategy to advance circular economy principles and bolster environmental and agricultural sustainability, especially in soilless cultivation. This study evaluates the viability of three organic by-products—wood fiber (WF), coffee silverskin (CS), and brewer’s spent grains (BSGs)—as partial peat replacements in horticultural substrates. Ten growing media formulations were assessed, incorporating increased doses (0–40% v/v as peat replacement-PR) of each alternative by-product. The effects on physical and hydraulic substrate properties, along with plant growth traits, were examined using two ornamental Salvia genotypes, ‘Victoria’ and ‘Amistad’. To synthesize the multivariate growth data into a single, biologically meaningful metric, based on the first principal component, a Growth Index (GI), a PC1-derived index, was calculated, providing a powerful, unified metric to rank substrate efficacy. WF-based substrates exhibited increased porosity and diminished water retention, whereas media enriched with CS and BSG enhanced moisture availability, particularly at 20–40 PR. The bulk density was highest at PR40 for both WF and BSG treatments, and at PR20 in CS-based substrates. Electrical conductivity increased in CS and BSG treatments with rising PR levels. The results on the vegetative growth of ornamental sages have highlighted that differential PR rates are required depending on the specific organic by-product and plant genotype. In ‘Victoria’, GI indicates that a 20% replacement of peat with BSG provided the optimal conditions for holistic plant development; the lowest GI for WF substrates across nearly all peat replacement levels indicated that it was the most detrimental alternative for this cultivar. In ‘Amistad’, the analysis of the GI scores revealed that the CS20 and BSG20 of peat replacement yielded the highest overall growth, with GI scores significantly greater than those of the peat control. CS10 and BSG40 also showed high GI scores in ‘Amistad’. WF10 had GI scores similar to those of the peat control. In general, the GI-based approach confirms that moderate inclusion of brewer’s spent grain (BSG20) is a highly effective peat replacement for both genotypes. At the same time, coffee silverskin (CS) is particularly effective for the ‘Amistad’ genotype. This analysis underscores that optimal substrate formulation is not only dependent on the amendment type and rate but also critically on the plant genotype. Full article

Underutilized leafy greens are considered as functional plant species primarily due to their resilience to abiotic stress factors, low nutrient requirements, and high nutritional value. Over the past 30 years, many experiments have been conducted to identify nutrient-efficient species, cultivars, landraces, and ecotypes, but few have successfully entered mainstream agriculture. The integration of these species into advanced horticultural systems, such as hydroponics, has the potential to further strengthen their impact on sustainable agriculture by minimizing use of resources, enabling year-round cultivation, and improving the nutritional profile of the harvested produce. As leafy vegetables, a primary food safety concern is the accumulation of nitrates in the leaves. In hydroponics, this issue is usually addressed by balancing the NH₄-N/total-N ratio (N_r) in the nutrient solution. Provided that the plant responses to high ammonia supply are species-dependent, three wild leafy greens, iceplant, corn salad, and common purslane, were grown in a soilless culture, with perlite as the substrate, under low (0.04) and high (0.12) N_r on a molar basis. Additionally, the potential of protein hydrolysates (PH) and seaweed extracts (SW) to alleviate plant tolerance to excess ammonia supply was also investigated. In terms of yield, high N_r led to significant yield restrictions in iceplant that reached 28%, while on corn salad, it had a positive impact, with yield increasing by 18%. Both biostimulant applications enhanced iceplant productivity only under optimal N_r conditions (0.04). Apart from yield responses, biofertilizers had no substantial impact on the plant nutrient profile. In contrast, high N_r suppressed nitrate accumulation in fresh leaves, while enhancing micronutrient uptake in all three plant species. In conclusion, this study highlights the pivotal role of biostimulants as plant stress protectors and growth regulators and identifies the optimal N_r ratio for maximizing the yield and quality performance of corn salad, iceplant, and common purslane in soilless cultivation systems. Full article