Microgreens are relatively novel food with high nutrition and dietary benefits that can be influenced by the growing medium. Two experiments were performed to develop an optimum media for microgreensfrom kale (Brassica oleracea L. var. acephala), Swiss chard (Betavulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), and amaranth (Amaranthus tricolour L.). Experiment 1 was screening of media T1 = 30% vermicast + 40% sawdust + 30% perlite; T2 = 30% vermicast + 50% sawdust + 20% perlite; T3 = 50% vermicast + 30% sawdust + 20% perlite; T4 = 30% vermicast + 40% sawdust + 30% mushroom compost; T5 = 30% vermicast + 20% sawdust + 20% perlite + 30% mushroom compost; and a negative control (NC) = 50% sawdust + 50% mushroom compost. The positive control was Promix BX™ potting mix alone. Experiment 2 was to test the efficacy of two different sources of mushroom compost (White oyster mushroom compost (MC1) and Shiitake mushroom compost (MC2)) added to media T1 to T5 above. The results showed that the media physicochemical properties varied across treatments. Higher chemical parameters were obtained for T4, T5, and media containing MC1. Porosity and water retention were increased in media containing MC2 compared to the other.Seed germination, plant height, and microgreen yield were statistically (P>0.05) enhanced by T2 and T4 that contained MC2 compared to the rest. Microgreens yield was approximately three times higher in T2 and 4 with added MC2, except the yield of arugula which was two times higher in these media compared to the control. Overall, T5 alone, and T2 and T4 with added MC2 were the most effective media for microgreen production. Future studies will assess microgreens’ nutrients in different media.

Keywords: leafy vegetable, natural amendment, organic food, sustainable farming, healthy food

Preharvest factors refer to management practices applied before the final harvest of crops that affect postharvest productivity and quality of the crop. Preharvest factors include 1) plant genotypic traits; 2) growing medium factors and amendments; 3) environmental factors (light quality, duration, intensity); 4) management practices (planting and harvest time, irrigation, and fertilization).¹ Natural amendments (organic natural material) are added to soil or growing media to enhance the fertility and/or the structure of soil, thereby helping plant growth and development.^2-5 Various natural amendments application was shown to differentially alter the physiochemical properties of growing media and provided higher nutrients that consequently improved the yield index of different crops.^6-8 Previous studies corroborated that adding vermicast into growing media promote aeration, porosity, capacity of holding water, and support microbial activity and antipathogenic response.^9-11

A study by Zhang et al.¹² indicated that fresh weight and leaf area were higher in two Plectranthus spp treated with vermicast compared to K-humate and NPK amendments, which can be associated with more balanced nutrients in vermicast. As confirmed by Iheshiulo et al.¹¹ kale (Brassica oleracea L. var. acephala)growth rate, leaf elongation, and fresh weight yield were improved by the application of natural amendments compared to Pro-mix BX alone as the control. The authors found that vermicast was the most effective amendment in enhancing the growth rate of kale that may relate to the presence of higher N content.Another popular natural amendment is sawdust produced from industrial wood waste and forestry with high carbon content. It provides substantial advantages for the environment including 1) promoting water holding capacity; 2) increasing soil porosity and aeration; and 3) providing good drainage.¹³ According to Singh et al.¹⁰ sawdust and vermicompost are locally available materials and environmentally friendlier alternatives compared to traditional strategies for microgreens production. There are limited studies regarding the effects of sawdust on plant production, in particular microgreens. A study by Agboola et al.¹⁴ revealed a delay in the initial growth response of tomato (Solanum lycopersicum) to sawdust but there was increase in response after 7days. The authors concluded that sawdust was economical medium substrate and an effective alternative to peat.

A research study done by Cheng confirmed that adding 30% sawdust into total soil treated with NPK (nitrogen, phosphorus, and potassium) compound fertilizer led to a significant increase in tomato yield in comparison with using sawdust alone. Mahboub Khomami et al.¹⁵ demonstrated that the application of vermicompost-sawdust extract caused a significant increase in yield and mineral nutrients of Syngoniumpodophyllum. A recent study by Lin et al.¹⁶ indicated that a combination of 60% vermicast + 40% sawdust mixed growing media noticeably enhanced growth factors including fresh/ dry weight, plant height, and leaf number in Swiss chard, pak choi, and kale microgreens. It was shown that the enhanced growth factors were linked to the positive effects of vermicast-vermicast mixed media on growing media physicochemical factors including enhanced microbial activities and nutrient mineralization. Mushroom compost is a mixture of different natural compost like chopped straw, gypsum, manure, and water used to grow mushrooms. It is known to possess potential benefits for plant growth and growing media properties including 1) supplying readily available macro and micronutrients; 2) increasing water retention capacity and drainage; 3) supporting beneficial micro-organisms. Renaldo et al.¹⁷ reported higher germination rate and growth parameters including root/ shoot ratio, shoot/ root day mass cucumber (Cucumis sativus) treated with mushroom compost and biochar compared to corn stalks. It was demonstrated that the higher decomposition rate in mushroom compost, hence an increased nutrient availability may be connected to enhanced growth indices. In the work done by Hernández et al.¹⁸ enhanced germination percentage, fresh shoot weight, and yield in red baby leaf lettuce by mushroom compost application. Interestingly, the results obtained from previous studies present obvious affirmation regarding the potential effects of mushroom compost on growth attributes and plant productivity.

Microgreens are immature seedlings of edible vegetables and herbs, which are known to possess high nutritional values and biological functions.^19,20 According to literature, microgreens possess higher levels of phytonutrients such as ascorbic acid, b-carotene, a-tocopherol, and phylloquinone, vitamins, and minerals compared to their mature leaf counterparts.^20,21 Kale, Swiss chard, and pak choi have been shown to have  high vitamins A, C, and K, functional lipids, carotenoids, and mineral nutrients content.^19,22 However, microgreens response to variations in growing media has not been well studied. Therefore, the objective of the current study was to determine properties exhibited by different mixed proportions of growing media and their effects on plant growth components and yield of different plant species of microgreens.

Two separate greenhouse experiments were carried out between July and December 2020 to formulate and optimize mixed growing media. Each experiment was repeated, and the data was merged due to a small coefficient of variationof less than 7%. Seeds of kale (Brassica oleracea L. var. acephala), Swiss chard (Beta vulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), pak choi (Brasica rapa var chinensis), and amaranth (Amaranthus tricolour L.); and perlite, Pro-mix BX and vermicast were purchased from Halifax Seeds, NS, Canada. Sawdust was obtained from Thermal Woods Inc., NB; and Shiitake (Lentinula edodes) and white oyster (Pleurotusostreatus) mushroom compost from Maritime Gourmet Mushroom, Great Village, NS.

Formulation and testing of media

Table 1 shows the mixture for each growing media treatment. 

Physical characteristics of growing media in terms of bulk density, porosity, and field capacity were determined in triplicate as suggested by Peterson,²³ with slight modifications. Bulk density (Db) was obtained from the weight (M) and volume (V1) of the soil using a graduated glass cylinder after continuous tapping until there was not any visible change in soil volume and calculated as:

$\text{Bulk density}=\raisebox{1ex}{$\text{M}$}\!\left/ \!\raisebox{-1ex}{${\text{V}}_1$}\right.$ -------------- (1)

The soil was air-dried under room temperature (ca. 22^oC) after which 15.24-cm plastic pots with drainage holes were filled with known mass of the soil (Ms) and weighed (Msp). The potting soil placed in a saucer was saturated with distilled water. After 48hr, the saturated soil weight (Msat) was recorded. To drain the free water, the saucer was removed, and the drained soil (Mdrained) was weighed after 72hr under atmospheric pressure. Then, the drained soil was spread uniformly in a tray to dry at ambient temperature for 72hr and weighed (Mdried).

$\text{Porosity }=\raisebox{1ex}{$\text{Ms}$}\!\left/ \!\raisebox{-1ex}{${\text{V}}_2$}\right.$ --------------(2)

$\text{Field capacity }({\text{F}}_{\text{c}})=\frac{{\text{M}}_{\text{drained}}-{\text{M}}_{\text{sp}}}{{\text{M}}_{\text{s}}}\text{ x }100$ --------------(3)

The chemical characteristics of growing media including pH, salinity, electrical conductivity (EC), and total dissolved solids (TDS) were determined by the mixture of 500g of each media and 400mL of deionized water. These chemical properties were recorded by an ExStik® II EC500 waterproof pH/conductivity meter (Extech ITM Instruments Inc., Canada).

Seeding

Seeds of kale, Swiss chard, arugula, pak choi, and amaranth were sown by broadcasting uniformly on a flat plastic tray (19cm length x 12cm width x 2.5cm deep) containing the different mixed media (200g) under high pressure sodium lamp. The temperature cycle in the growth room from seedling stage to time of harvest was 24^o/22°C and 16/8hrs day/night light regime. The seedlings were irrigated every two days. No fertilizer was used.

Seed germination, plant growth and yield

Germination data were collected after six days of sowing. Plant height was measured by using a ruler at six days interval. The microgreens were harvested and weighed as the yield (whole shoot area growing above ground) after 14days of sowing using Ohaus Navigator® XT Portable Balance (ITM Instruments Inc., Canada). The optimum proportion of mixed media was selected for the subsequent experiments.

Optimization of mixed media

In the second experiment, new formulations of different mixed growing media were made from two different mushroom composts sources i.e., White oyster mushroom compost (MC1) and Shiitake mushroom compost (MC2)as presented in Table 2.

Experimental Design and Statistical Analysis

The experiment was arranged in a completely randomized design with three replications. Plastic trays were rearranged every two days to minimize variations in microclimate of the greenhouse. Data was analyzed by 2-way ANOVA using Minitab (version 18.3), and the Fisher method was applied to compare treatment means at α = 0.05 when ANOVA showed P≤0.05. Correlation analysis was performed to identify the relationship between media quality components and plant data. Multivariate analysis by principal component analysis (PCA) was performed using GenStat. Graphs were plotted using Microsoft Excel.

Experiment 1

Growing media properties

Physicochemical properties of the different growing media were significantly (P<0.05) different (Table 3). It was found that NC and T4 had a significantly (P<0.05) higher bulk density of an average of 0.184 g/cm³ compared to an average of 0.150g/cm³ for the other treatments. The highest porosity and field capacity were observed by T4 followed by NC and T1 but T3 recorded the least.

The different growing media had distinct pH ranging from 5.8 to 7.3. The pH for T4 and T5 was significantly (P<0.05) higher than the other treatments. Different trends for salinity, electrical conductivity and total dissolve solids were observed among the treatments (Table 3). The salinity, electrical conductivity, and total dissolved solids were higher in T4, T5, and NC compared to other treatments.

Plant growth

The effects of the different mixed growing media, plant species, and the interaction of growing media × plant species on seed germination and plant height were significant (P < 0.05) (Figures 1A&B). Seed germination of Swiss chard and kale were increased by ca. 18% and 13% in T5 respectively, compared to their counterparts in the PC. In amaranth, T4 showed the highest germination percentage that was 25% higher than that of the control. Moreover, the different growing media did not exhibit a positive effect on arugula seedgermination as the highest rate was observed in PC (Figure 1A). Among the microgreen plant species, the overall trend for germination percentage was arugula (76.9%) > amaranth (61.5%) = kale (61.3%) > Swiss chard (55.6%) (Figure 1A). Consistently, microgreens plant height was significantly (P < 0.05) increased by T5 and PC in all the plant species (Figure 1B). Overall, the trend for the plant height was arugula (4.9cm) > kale (4.7cm) > Swiss chard (4.1cm) >amaranth (2.6cm) (Figure 1B).

Figure 1 Germination (A) and plant height (B) of Swiss chard (Beta vulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), amaranth (Amaranthus tricolour L.), and kale (Brassica oleracea L. var. acephala) microgreens affected by different growing media:T1: 30% vermicast + 40% sawdust + 30% perlite; T2: 30% vermicast + 50% sawdust + 20% perlite; T3: 50% vermicast + 30% sawdust + 20% perlite; T4: 30% vermicast + 40% sawdust + 30% mushroom compost; T5: 30% vermicast + 20% sawdust + 20% perlite+ 30% mushroom compost; PC: Pro-mix BX™ potting medium alone; NC: 50% sawdust + 50% mushroom compost. (n = 3); significant at P < 0.05.

The correlation analysis between physicochemical attributes of mixed growing media and plant growth factors is presented in Table 4. In general, there was a negative correlation between physical factors of mixed growing media and the plant growth factors in all tested microgreens. However, there was a significant positive correlation between pH, salinity, EC, and TDS of the mixed growing media and seed germination in amaranth.

Association between media and plant data

A Principal component analysis (PCA) followed by a biplot was employed to examine the association between physicochemical characteristics of growing media and plant data affected by the variations in growing media (Figure 2). T5 followed by T4 are close to the origin of the axes suggesting higher stability in these treatments compared to the others that are located at the periphery. Therefore, T5 and T4 can be associated with improved physicochemical properties of the growing media and plant growth components of all the microgreen plant species. Interestingly, the chemical parameters of growing media are strongly influenced by different growing media formulations compared to that of the physical parameters. The overall trend for media chemical parameters was pH > EC> TDS> Salinity. In addition, amaranth germination and seedling height, and Swiss chard seedling height followed by kale seedling height were strongly influenced by the interaction of growing media × plant species compared to that of the arugula plant. Finally, T5 and T4 were selected as desirable media for microgreen production compared to the others irrespective plant species.

Figure 2 Ranking total × total biplot for comparison of treatment × plant species interaction effects on all growth and physicochemical growing media properties variations in all microgreens. PRST: Porosity; BD: Bulk density; FC: Field capacity; SAL: Salinity; EC: Electrical conductivity; TDS: Total dissolved solid; GRCH: Swiss chard germination; GRA: Arugula germination; GRK: Kale germination; AMGR: Amaranth germination; HCH: Swiss chard height; HA: Arugula height; HK: Kale height; HAM: Amaranth height.T1: 30% vermicast + 40% sawdust + 30% perlite; T2: 30% vermicast + 50% sawdust + 20% perlite; T3: 50% vermicast + 30% sawdust + 20% perlite; T4: 30% vermicast + 40% sawdust + 30% mushroom compost; T5: 30% vermicast + 20% sawdust + 20% perlite+ 30% mushroom compost; PC: Pro-mix BX™ potting medium alone; NC: 50% sawdust + 50% mushroom compost.

Experiment 2

Growing media properties

The physicochemical properties of the growing media were significantly (P<0.05) different from each other, possibly due to the distinct composition of each growing media (Table 5). It was found that PC had the highest bulk density among treatments. However, treatments formulated with White oyster mushroom compost (MC1) had a higher bulk density of an average of 0.095g/cm³ compared to an average of 0.087g/cm³ for treatments formulated with Shiitake mushroom compost (MC2).

The highest porosity was observed in PC followed by T4.2 and the least were T2.1. Field capacities of media PC, T3.2 and T1.2 were the highest compared to the others. Consistently, field capacity was increased in growing media formulated with MC2 compared to MC1.Moreover, T4.1 and NC1 had higher pH of an average of 7.4 compared to an average of 6.2 for T1.2 and PC. The overall trend for salinity, EC and TDS of the growing media parameters were different among treatments. The highest salinity, EC, and TDS were observed in NC1 followed by T3.1 and T1.1 (Table 5).

Plant growth

The ANOVA showed that seed germination, plant height, and yield indexin all tested microgreen species were significantly (P<0.05) influenced by the different growing media, plant species, and their interaction (Figure 3A-C). Swiss chard, arugula, and pak choi seed germination were increased by ca.9% in T2.2 and T4.2, ca.59% in T2.2 and T3.2, and ca.25% in T2.2, respectively, compared to their counterparts that were grown in the PC. The different mixed growing media did not exhibit positive effect on seed germination of arugula as the highest rate was observed in the PC (Figure 3A).

Similarly, the different growing media did not have a positive effect on seed germination of kale as the highest rate was observed in PC (Figure 3A). Moreover, microgreens plant height was significantly (P < 0.05) increased by T2.2, T4.2, PC in all the plant species (Figure 3B). Contrary to this, T1.1, NC1, NC2 followed by T4.1 reduced plant height of all the microgreen plants. The yield index was significantly (P < 0.01) increased by T2.2 and T4.2 in all the plant species (Figure 3C). The yield of Swiss chard, arugula, and kale increased by 31%, 17%, and 43% in T2.2 respectively compared to their PC counterparts. However, pak choi yield was enhanced in T4.2 by 35% compared to PC (Figure 3C).

Figure 3 Germination (A); plant height (B); yield (C) of Swiss chard (Beta vulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), pak choi (Brasica rapa var chinensis.), and kale (Brassica oleracea L. var. acephala) microgreens affected by different growing media including T1.1: 30% vermicast + 30% sawdust + 40% MC1; T1.2: 30% vermicast + 30% sawdust + 40% MC2; T2.1: 30% vermicast + 30% sawdust + 10% perlite + 30% MC1; T2.2: 30% vermicast + 30% sawdust + 10% perlite + 30% MC2; T3.1: 30% vermicast + 40% sawdust + 30% MC1; T3.2: 30% vermicast + 40% sawdust + 30% MC2. T4.1: 30% vermicast + 20% sawdust + 20% perlite + 30% MC1; T4.2: 30% vermicast + 20% sawdust +20% perlite + 30% MC2. NC1: 50% sawdust + 50% MC1; NC2: 50% sawdust + 50% MC2; Positive control: Pro-mix BX™ potting medium alone. ***, significant at P<0.001.

Correlation analysis results indicated that there was a significant (P<0.05) positive correlation between porosity and yield of most microgreen species, while there was significant negative correlation between bulk density and field capacity and the measured growth parameters of the microgreens. Furthermore, there was significant (P<0.05) negative correlation between pH, salinity, EC, and germination of pak choi and kale. There was no significant (P>0.05) correlation between TDS and the measured traits in all the microgreens (Table 6).

Association among media and plant components

The PCA demonstrated the association among physicochemical parameters of growing media and seed germination and growth parameters affected by the variations in growing media formulations (Figure 4). T4.2 showed a high association and stability compared to the other treatments located at the periphery of the axes. Thereby, the enhanced growth traits in all the microgreens can be attributed toT4.2. Seed germination, plant height and yield were strongly influenced by the interaction between growing media × microgreen plant species.

Figure 4 Ranking total × total biplot for comparison of treatment × plant species interaction effects on all growth and physicochemical growing media properties variations in all microgreens. PRST: Porosity; BD: Bulk density; FC: Field capacity; SAL: Salinity; EC: Electrical conductivity; TDS: Total dissolved solid; GRCH: Swiss chard germination; GRA: Arugula germination; GRP: Pak choi germination; GRK: Kale germination. HCH: Swiss chard height; HA: Arugula height; HPAK: Pak choi height; HK: Kale height. YCH; Swiss chard yield; YA: Arugula yield; YP: Pak choi yield; YK: Kale yield. T1.1: 30% vermicast + 30% sawdust + 40% MC1; T1.2: 30% vermicast + 30% sawdust + 40% MC2; T2.1: 30% vermicast + 30% sawdust + 10% perlite + 30% MC1; T2.2: 30% vermicast + 30% sawdust + 10% perlite + 30% MC2; T3.1: 30% vermicast + 40% sawdust + 30% MC1; T3.2: 30% vermicast + 40% sawdust + 30% MC2. T4.1: 30% vermicast + 20% sawdust + 20% perlite + 30% MC1; T4.2: 30% vermicast + 20% sawdust +20% perlite + 30% MC2. NC1: 50% sawdust + 50% MC1; NC2: 50% sawdust + 50% MC2; Positive control: Pro-mix BX™ potting medium alone.

In the present work, the effects of different natural amendments on the physicochemical attributes of formulated growing media and the response of different microgreens plant species were studied in indoor cultivation system. The results indicated that T4 and T5 growing media had considerable effect on seed germination while T5 and PC growing media had the greatest effect on plant height of all the microgreen species (Figure 1A). Physicochemical properties of the growing media play a significant role in seed establishment and consequently, plant growth.

Amendments are considered one of the major strategies to improve the physical features of growing media such as drainage, water retention capacity, and porosity, which in turn affect plant growth factors.^24-26 In this experiment, it seems that the structure and physicochemical traits of media T4 and T5 were ameliorated, mostly by the presence of the mushroom compost and as a result, germination and plant height of all microgreens were increased.

In agreement with current results, Vahid Afagh et al. attributed improved crop productivity to increased aeration and water holding capacity by adding 15% mushroom compost into a growing medium. It has been shown that high bulk density reduces root growth and yield of lettuce. However, the bulk density of T5 was about 0.158 g/cm³, which was below root-restriction threshold bulk density (1.66g/cm³). This results, together with the average value of porosity in T5, could be responsible for the improved plant height in this media. In contrast, decreased plant height of arugula in T4 can be ascribed to high level of salinity (Figure 1B), as confirmed by significant negative correlation between arugula plant height and media salinity (Table 4). Similar to our results, Warrence et al. explained that root penetration and root growth can be negatively influenced by the higher level of salinity and EC. Addition of perlite and wood-based substrates into growing media can diminish the negative effects of high EC and salinity levels.^27,28 Accordingly, the more positive effects of T5 on plant height compared to T4 can be explained by the presence of high portions of perlite in the former compared to the latter. Moreover, the presence of mushroom compost in T4 and T5 may supply more nutrients for plants that may explain the observed higher germination and plant height in these media.²⁹ PCA analysis results validated T4 and T5 enhancement of microgreens plant performance compared to other treatments (Figure 2). As a result, T4 and T5 were selected for further investigation in the Experiment 2.

Mixed media with added White oyster mushroom compost (MC1) had higher bulk density and lower porosity, field capacity, and recorded low plant growth (Table 5).Given that the optimum range of pH for leafy greens is 5.5 to 6.5,³⁰ the lower growth rate in the mixed media made from MC1 can be attributed to the high pH, which negatively affects plant nutrients availability.³¹ It is well known that salinity adversely affect water and nutrient uptake by reducing osmotic potential and leading to nutrient imbalance in plants,^32,33 in addition to a negative relationship between EC and TDS and soil nutrients availability.^34,35 In the present study, a high salinity and EC levels were observed in growing media made from MC1 (Table 5). Therefore, a reduction in plant growth in T1.1 and NC1 can be attributed to high EC and salinity levels in these media. Like our results, Zhang et al.¹² reported negative effects of high EC levels on plant growth and productivity. These results were further confirmed by correlation data analysis in which there was a negative relationship between germination, plant height, yield factors on one hand, and high salinity, EC, and TDS levels on the other hand (Table 6).

Consequently, there was high germination rate, plant height, and yield of microgreens grown in mixed media added with Shiitake mushroom compost (MC2), particularly T2.2 and T4.2 (Figure 3).These results could be due to the improved physical factors such as porosity and field capacity in these media. Moreover, the presence of MC2 in the media may provide more readily available nutrients for the plants compared to MC1. In support of this, higher levels of nutrients including N, C, P, Ca have been reported in Shiitake mushroom compost compared to White oyster mushroom compost by Hernández et al.¹⁸ and Kumar et al.²⁹ In addition, PCA results suggested that growing media made from MC2 were better for the improvement of plant growth and yield performance in all tested microgreens (Figure 4). In agreement with our results, it previously shown that application of mushroom compost enhanced germination rate and seedling growth in cucumber and lettuce plants.^17,18 Furthermore, Lin¹⁶ demonstrated that growth parameters including plant height, leaf number, fresh and dry mass of Swiss chard, pak choi, and kale were drastically enhanced when grown in the mixed media formulated with 60% vermicast + 40% sawdust.^36-43

The results of this study demonstrated variations in physicochemical parameters and the effectiveness of different proportions of mixed media and their impact on the growth and yield of microgreens. The media containing Shiitake mushroom compost substantially promoted plant growth and yield in all microgreen plant species due to improved physicochemical parameters of the growing media and possibly superior nutrient status. In contrast, the reduced plant growth in media containing White oyster mushroom compost may be attributed to the higher salinity, EC, and TDS levels. Overall, it was found that T2.2 and T4.2 were the most effective treatments in improving germination rate, plant height, and yield in all microgreens. We concluded that adding Shiitake mushroom compost and perlite into a growing media will enhancemedia physical featuresand make nutrients more available to microgreen plants. Future studies will evaluate the effect of different mixed growing media on the chemical composition of microgreens.

Funding was provided by Nova Scotia Graduate Student (NSGS) and Natural Sciences and Engineering Research Council of Canada (NSERC).

The authors wish to thank Dr. Samuel Asiedu for their generous assistance and support in this study.

The authors declare no conflicts of interest regarding the publication of this paper.

1. Aftab T. A review of medicinal and aromatic plants and their secondary metabolites status under abiotic stress. Journal of Medicinal Plants. 2019;7(3):99‒106.
2. Alam MK, Rahim MA, Rahman MH, et al. Effects of organic fertilizers on the seed germination and seedling vigour of tomato. Building Organic Bridges. 2014;1:49‒52.
3. Trivedi P, Singh K, Pankaj U, et al. Effect of organic amendments and microbial application on sodic soil properties and growth of an aromatic crop. Ecological engineering. 2017;102:127‒136.
4. Abbott LK, Macdonald LM, Wong MTF, et al. Potential roles of biological amendments for profitable grain production–a review. Agriculture, ecosystems & environment. 2018;256:34‒50.
5. da Costa Jaeggi MEP, Rodrigues RR, Pereira IM, et al. Vegetative Development of Radish Seedlings in Different Organic Substrates. Journal of Experimental Agriculture International. 2019;1‒8.
6. Sarma B, Gogoi N. Germination and seedling growth of Okra (Abelmoschus esculentus L.) as influenced by organic amendments. Cogent Food & Agriculture. 2015;1(1):1030906.
7. Mahmud M, Abdullah R, Yaacob J. Effect of vermicompost amendment on nutritional status of sandy loam soil, growth performance, and yield of pineapple (Ananas comosus var. MD2) under field conditions. Agronomy. 2018;8(9):183.
8. Celestina C, Hunt JR, Sale PW, et al. Attribution of crop yield responses to application of organic amendments: A critical review. Soil and Tillage Research. 2019;186:135‒145.
9. Ahirwar CS, Hussain A. Effect of vermicompost on growth, yield and quality of vegetable crops. International Journal of Applied and Pure Science and Agriculture. 2015;1(8):49‒56.
10. Singh N, Rani S, Chaurasia OP. Vegetable Microgreens Farming in High‒Altitude Region of Trans‒Himalayas to Maintain Nutritional Diet of Indian Troops. Proceedings of the National Academy of Sciences, India Section B: Biological Sciences. 2020;90(4):743‒752.
11. Iheshiulo EMA, Abbey L, Asiedu SK. Response of Kale to single‒dose application of k humate, dry vermicasts, and volcanic minerals. International Journal of Vegetable Science. 2017;23(2):135‒144.
12. Zhang B, Wijesundara NM, Abbey L, et al. Growing medium amendments effect on growth, secondary metabolites, and anti‒streptococcal activity of two species of Plectranthus. Journal of Applied Research on Medicinal and Aromatic Plants. 2017;5:53‒59.
13. Maharani R, Yutaka T, Yajima T, et al. Scrutiny on physical properties of sawdust from tropical commercial wood species: Effects of different mills and sawdust's particle size. Indonesian Journal of Forestry Research. 2010;7(1):20‒32.
14. Agboola OO, Oseni OM, Adewale OM, et al. Effect of the use of sawdust as a growth medium on the growth and yield of tomato. Annales of West University of Timisoara. Series of Biologyl. 2018;21(1):67‒74.
15. Mahboub Khomami A, Padasht MN, Ajili Lahiji A, et al. The effect of sawdust vermicompost extract on Syngonium podophyllum growth and nutrition. Journal of plant nutrition. 2019;42(4):410‒416.
16. Lin S. Combined Effects of Vermicast‒Trichoderma‒Sawdust on Kale, Swiss Chard, and     Pak Choy Growth.  (Unpublished master's thesis). Dalhousie University, Halifax, Nova Scotia, Canada. 2020.
17. Renaldo B, Gaius E, Gregory G, et al. Effects of organic amendments on early plant growth. Conference: 20th World Congress of Soil Science At: Jeju, Korea. 2014.
18. Hernández D, Ros M, Carmona F, et al. Composting Spent Mushroom Substrate from Agaricusbisporus and Pleurotusostreatus Production as a Growing Media Component for Baby Leaf Lettuce Cultivation under Pythium irregulare Biotic Stress. Horticulturae. 2021;7(2):13.
19. Vidal NP, Pham HT, Manful C, et al. The use of natural media amendments to produce kale enhanced with functional lipids in controlled environment production system. Scientific reports. 2018;8(1):14771.
20. Kyriacou MC, El‒Nakhel C, Graziani G, et al. Functional quality in novel food sources: Genotypic variation in the nutritive and phytochemical composition of thirteen microgreens species. Food Chemistry. 2019;277:107‒118.
21. Pinto E, Almeida AA, Aguiar AA, et al. Comparison between the mineral profile and nitrate content of microgreens and mature lettuces. Journal of Food Composition and Analysis. 2015;37:38‒43.
22. Pham TH, Zaeem M, Fillier TA, et al. Targeting modified lipids during routine lipidomics analysis using HILIC and C30 reverse phase liquid chromatography coupled to mass spectrometry. Scientific Reports. 2019;9(1):5048.
23. Peterson JM. Soils‒Part 2: Physical Properties of Soil and Soil Water. 1999
24. Rawls WJ, Pachepsky YA, Ritchie JC, et al. Effect of soil organic carbon on soil water retention. Geoderma. 2003;116(1‒2):61‒76.
25. Cellier A, Gauquelin T, Baldy V, Ballini C. Effect of organic amendment on soil fertility and plant nutrients in a post‒fire Mediterranean ecosystem. Plant and soil. 2014;376(1):211‒228.
26. Karthikeyan M, Hussain N, Gajalakshmi S, et al. Effect of vermicast generated from an allelopathic weed lantana (Lantana camara) on seed germination, plant growth, and yield of cluster bean (Cyamopsis tetragonoloba). Environmental Science and Pollution Research. 2014;21(21):12539‒12548.
27. Zhang F, Tiyip T, Ding JL, et al. The effects of the chemical components of soil salinity on electrical conductivity in the region of the delta oasis of Weigan and Kuqa Rivers, China. Agricultural Sciences in China. 2009;8(8):985‒993.
28. Lee YH, Ahn BK, Sonn YK. Effects of electrical conductivity on the soil microbial community in a controled horticultural land for strawberry cultivation. Korean Journal of Soil Science and Fertilizer. 2011;44(5):830‒835.
29. Kumar P, Eid EM, Taher MA, et al. Biotransforming the Spent Substrate of Shiitake Mushroom (Lentinula edodes Berk.): A Synergistic Approach to Biogas Production and Tomato (Solanum lycopersicum L.) Fertilization. Horticulturae. 2022;8(6):479.
30. Gillespie DP, Kubota C, Miller SA. Effects of low pH of hydroponic nutrient solution on plant growth, nutrient uptake, and root rot disease incidence of basil (Ocimum basilicum L.). Hort Science. 2020;55(8):1251‒1258.
31. Shrivastava P, Kumar R. Soil salinity: A serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation. Saudi journal of biological sciences. 2015;22(2):123‒131.
32. Kaymakanova M, Stoeva N. Physiological reaction of bean plants (Phaseolus vulg. L.) to salt stress. Gen Appl Plant Physiology Special. 2008;(34):3‒4.
33. Corwin DL, Yemoto K. Salinity: Electrical conductivity and total dissolved solids. Soil Science Society of America Journal. 2020;84(5):1442‒1461.
34. Qados AMA. Effect of salt stress on plant growth and metabolism of bean plant Vicia faba (L.). Journal of the Saudi Society of Agricultural Sciences. 2011;10(1):7‒15.
35. Lvova L, Nadporozhskaya M. Chemical sensors for soil analysis: Principles and applications. In New pesticides and soil sensors. Academic Press. 2017;637‒678.
36. Abbey L, Pham TH, Annan N, et al. Chemical composition of kale as influenced by dry vermicast, potassium humate and volcanic minerals. Food research international. 2018;107:726‒737.
37. Abbey L, Rao SA, Hodgins LN, et al. Drying and rehydration of vermicasts do not affect nutrient bioavailability and seedling growth. Amer J Plant Nutr Fert Technol. 2013;3(1):12‒21.
38. Arnon DI, Johnson CM. Influence of hydrogen ion concentration on the growth of higher plants under controlled conditions. Plant Physiology. 1942;17(4):525.
39. Akbarimoghaddam H, Galavi M, Ghanbari A, et al. Salinity effects on seed germination and seedling growth of bread wheat cultivars. Trakia journal of Sciences. 2011;9(1):43‒50.
40. Bajaj S, Khan A. Antioxidants and diabetes. Indian journal of endocrinology and metabolism. 2012;16(Suppl 2):S267.
41. Kyriacou MC, Rouphael Y, Di Gioia F, et al. Micro‒scale vegetable production and the rise of microgreens. Trends in Food Science & Technology. 2016;57:103‒115.
42. Lech M, Fronczyk J, Radziemska M, et al. Monitoring of total dissolved solids on agricultural lands using electrical conductivity measurements. Applied Ecology and Environmental Research. 2016;14(4):285‒295.
43. Machado RMA, Serralheiro RP. Soil salinity: effect on vegetable crop growth. Management practices to prevent and mitigate soil salinization. Horticulturae. 2017;3(2):30.