Mushroom Spawn and Its Effects on Mushroom Growth and Development: A Systematic Review

Abstract

Mushrooms are among the most important indoor-grown horticultural cash crops. Recent increases in consumption are driven by shifts toward healthier diets and a growing vegan population. Mushroom spawn is one of key factors that influence consistency, quality, and the yield of mushrooms. Many studies of mushroom spawn have been published but the performance of mushroom spawn under different conditions has not been summarised. Comprehensive literature searches were conducted to identify the effects of spawn on biological efficiency, and 40 publications were included in this systematic review. Most of the studies were conducted on oyster mushroom (Pleurotus spp.), and grain spawn was popularly used when studying mushroom. Spawn type and rate were demonstrated to affect mycelium growth, which directly influenced mushroom yield. The use of liquid spawn increased mycelium growth, reduced spawn running time, and enhanced mushroom yield. Most studied cases used spawn rates of 3–5% and the biological yield efficiency (BE) of Pleurotus spp. was varied from 5.18 to 173.38% if using grain spawn. The BEs of Hericicum erinacea and Volvariella volvacea inoculated with grain spawn were lower at 22.3–44.4% and 9.42–15.79%, respectively. Recently developed stick and block spawn types seem to be promising spawn with a BE ranging from 68.65 to 70.94%.

1. Introduction

Mushrooms are widely consumed due to their flavour, taste, nutritional benefits, and medical values. Mushrooms are fat- and cholesterol-free, low in sodium, and rich in protein, fibre, vitamins, and antioxidants [1,2]. As a result, mushrooms are utilised widely as food, medicine, and dietary supplements all over the world [3,4]. With an increasing vegan population and diet shift toward healthier food, the consumption and market growth of mushrooms is increasing at a significant rate. The calculation based on FAO’s data showed that average mushroom consumption per capita has increased significantly from around 4.7 kg in 2013 to around 6.2 kg annually in 2023 [5]. The largest market share is held by Asia-Pacific countries, driven by higher mushroom consumption per capita. For example, China consumed nearly 64 kg mushroom per capita in 2021 [6].

Commercial mushrooms are typically cultivated on lignocellulosic agricultural residues such as straw, sawdust, sugarcane bagasse, cotton seed hush, corn cob, and corn stalk. These agricultural wastes are used as the base substrate to grow mushrooms commercially. In addition, nitrogen supplement sources including bran, animal dung, and seed hulls are also added to improve mushroom yield [7,8,9]. Global mushroom production has risen significantly in recent years, driven by increased consumption, the adoption of modern cultivation techniques, and improvements in logistics and preservation [6,10]. While a few factors have been identified to influence the yield of mushrooms (e.g., spawn, substrate ingredients, supplements, and growing conditions) [11,12,13], spawn is one of the primary factors that contribute for the success of mushroom production, together with substrate formulation and environmental conditions [14].

Spawn refers to the cultured mycelium of a mushroom grown on a suitable substrate, which serves as the seed material for mushroom cultivation. It is a propagative material consisting of mushroom mycelium combined with a suitable substrate that supports the optimal growth of mushrooms. Mushroom spawn is one of the main factors that affect the consistent growth, quality, and efficiency of mushrooms [14]. Spawn rate (the proportion of mushroom spawn added into substrate), type of spawn, and spawn quality were recorded to affect mushroom yield. A higher dose of spawn reduced the duration for the full colonisation of the substrate and promoted primordia initiation [1]. High-quality spawn promoted mycelial growth and efficiently colonised the substrate, contributing to the development of a healthy and early crop [14]. However, the performances of mushroom spawn have not been summarised under different conditions (mushroom species, growing conditions, and experimental set-up). Therefore, the main objective of this review is to quantify and summarise the influence of mushroom spawn, including types, rate, preparation, quality, and application of spawn, on biological efficiency yield based on mushroom species, substrate materials, and supplements. This review aims to summarise current knowledge on mushroom spawn types, quality parameters, and their effects on yield and biological efficiency under various cultivation conditions, with a focus on identifying knowledge gaps and practical recommendations for growers.

2. Materials and Methods

2.1. Study Design

A systematic review was conducted to summarise the available evidence and provided an overview of different mushroom spawn types and inoculation rates to increase mycelium and mushroom yield as well as biological efficiency. The Preferred Reporting Items for Systematic Reviews and Meta-analysis statement 2020 (PRISMA 2020) was applied in this review [15].

2.2. Search Strategy

The literature search was conducted using five major databases. ScienceDirect (up to 30 April 2025), Google Scholar (up to 14 May 2025), Scopus^® (up to 20 May 2025), CAB abstract (up to 30 October 2025), and Web of Science (up to 30 October 2025) databases were searched to identify the relevant literature published from 2015 to 2025 to ensure that the review reflects recent developments in mushroom spawn technology. It is acknowledged that earlier foundational studies exist and may provide additional context not covered in this review. The key search terms for mushroom spawn, “spawn type”, “spawn rate”, “spawn medium”, and “spawn culture”, were utilised in conjunction with “mushroom yield”.

The article search was “TITLE-ABS-KEY (“spawn type”) OR TITLE-ABS-KEY (“spawn rate”) OR TITLE-ABS-KEY (“spawn substrate”) OR TITLE-ABS-KEY (“spawn medium”) OR TITLE-ABS-KEY (“spawn culture”) AND TITLE-ABS-KEY (mushroom AND yield)) AND PUBYEAR > 2014 AND PUBYEAR < 2026 AND (EXCLUDE (LANGUAGE, “Chinese”) OR EXCLUDE (LANGUAGE, “Portuguese”) OR EXCLUDE (LANGUAGE, “Russian”) OR EXCLUDE (LANGUAGE, “Spanish”).

As the searched functions in the Web of Science and CAB abstract databases allowed for us to search for title and abstract but not key works, the article search query was “ab: (“spawn type”) OR Title: (“spawn type”) OR ab: (“spawn rate”) OR Title: (“spawn rate”) OR ab: (“spawn medium”) OR Title: (“spawn medium”) AND ab: (“mushroom yield”) OR Title: (“mushroom yield”)”.

To ensure completeness, the reference lists of all included studies were manually screened for additional relevant publications. Only English-language papers were considered, which may have excluded some regional studies—particularly from areas with active mushroom research such as Asia and Eastern Europe. The potential for publication and language bias is therefore acknowledged as a limitation of this review.

2.3. Study Selection and Quality Assessment

Articles were included in the review if they met all the following criteria: (i) original research papers published between 2015 and 2025; (ii) presented original and quantitative data on at least one of the aspects of mushroom spawn such as spawn types, spawn rates, spawn medium, application spawn, and mushroom yield; and (iii) were written in English. Articles were excluded from the review if (i) they were reviewed articles, books, and book chapters; (ii) conducted to test the growth of mycelium; (iii) data were not related to the scope of the study. The articles were first screened for titles. Next, abstract and content were reviewed based on above inclusion and exclusion criteria. A summary of the review is presented in the flow chart (Figure 1).

Each study was then qualitatively assessed for methodological rigour using a simplified risk-of-bias framework adapted for agronomic and mycological experiments. Key criteria included replication, randomization, and base-growing substrate. Most studies were small-scale trials conducted under controlled conditions; growing conditions were not always explicitly reported. Consequently, the findings summarised in this review are interpreted as hypothesis-generating rather than prescriptive, reflecting variability in experimental design and reporting standards across the included literature.

2.4. Data Extraction and Compilation

The mushroom spawns used in the experiments were categorised into four main groups: grain spawn, sawdust spawn, stick spawn, and liquid spawn. If one experiment had mixed types of spawn, various spawn rates, different mushroom species, or different growing medium to evaluate their effects on mushroom yield, it was separated into the main categories. Mushroom yield was generally recorded as gram per log. However, the weight logs were different among studies, so the yield was converted into gram per kg-growing substrate for consistent comparison.

The year of publication, experiment design, study location, duration, and mushroom yield parameters were collected. Some articles included multiple studies (e.g., multiple mushroom species or multiple types of spawn); the number of studies is higher than the number of articles. Priority was given to biological efficiency (BE); however, if BE was not available, mushroom yield data were extracted to see the effects of spawn on yield. Any missing information was recorded as “not reported” (NR) and were excluded from trend-based evaluations. When data or standard errors/standard deviations were not numerically reported, approximate values were extracted from published graphs using WebPlotDigitizer (version 5.0; developed by Ankit Rohatgi, Austin, TX, USA). The y-axis was calibrated using the figure’s scale and the mean bar height and the upper error bar were taken as the measure of variability (SD or SE, as indicated in the original figure legend). Endnote 21 (Clavirate, Los Angeles, CA, USA) was used to find duplicate articles. No statistical test was performed, considering the study’s aims.

3. Results and Discussion

The reviewed literature was dominated by studies on Pleurotus spp., particularly P. ostreatus and P. eryngii, which together represented more than half of all the included records. This dominance reflects the global prevalence of oyster mushroom cultivation and its adaptability to diverse agricultural residues. Evidence for other major cultivated mushrooms such as Agaricus bisporus, Lentinula edodes, and Ganoderma lucidum, was comparatively limited. Therefore, the conclusions drawn in this review primarily apply to Pleurotus species, and generalisations across all edible mushrooms should be made with caution until more balanced evidence becomes available.

3.1. General Characteristics of the Studies

A total of 110 articles were identified through databases and the literature search. After screening the abstract and content, only 40 articles met the inclusion criteria and were assessed for eligibility criteria. A total of 70 articles were excluded based on the following reasons: (1) if insufficient data were available for extraction; (2) if it was a review paper; and (3) its irrelevance to the review’s scope. Among the included articles, a majority were conducted in India (11 articles), followed by China (5) and Ethiopia (5).

3.2. Types of Mushroom Spawn

Mushroom spawn serves as the propagative unit in mushroom cultivation and is a critical factor influencing yield [13,16]. It can be produced by various methods including tissue culture, spore propagation, and cloning. Spawn consists of a carrier material infused with the vegetative mycelium of the target fungus, used to inoculate the cultivated substrate. Preparation of quality mushroom spawn requires knowledge, skill, variety of equipment, and aseptic and hygienic conditions [14,17]. A variety of materials and technologies have been developed for spawn production. In general, spawn-growing media need to be sterilised before inoculating pure mushroom mycelium. There are four main types of mushroom spawn, including grain spawn, sawdust spawn, stick spawn, and liquid spawn based on the growing carrier. Based on characteristics of growing media, spawn is divided into solid (grains, cellulosic materials, and others) and liquid spawn [18]. Solid spawn has been used since edible mushrooms were commercial cultivated in artificial logs in the early 20th century [18]. It consists of a pure culture of mycelium that grows on a solid substrate such as grain, sawdust, or agricultural waste, and is wildly used in most mushroom farms in China [18]. Submerged culture, which involves pure mushroom mycelium in liquid nutrient media, was developed more than 40 years ago [19].

In the last 10 years, studies of spawn on mushrooms have been conducted in various mushroom species, mainly focusing on oyster mushrooms, which are one of the most widely cultivated mushrooms (

Table 1. Number of studies on various mushroom varieties during 2015–2025.

Spawn Types	Mushroom Species		Number of Studies	References
	Common Name	Scientific Name
Grain	Oyster mushroom	Pleurotus spp.	35	[7,8,14,25,26,27,28,29]
	White shiitake	Lentinular squarrolus	1	[7]
	Shiitake	Lentinular edodes	1	[8]
	Lion mane	Hericium erinaceus	2	[9,30]
	Splitgill mushroom	Schizophyllum commune	1	[24]
	Straw mushroom	Volvariella volvacea	1	[31,32]
	Elm oyster mushroom	Hypsizygus ulmarious	1	[14]
	Button mushroom	Agaricus bisporus	1	[33]
	Lingzi mushroom	Ganoderma lucidum	1	[34]
Sawdust	Oyster mushroom	Pleurotus spp.	2	[16,35]
	Shiitake	Lentinula edodes	1	[36]
Stick	White oyster	Pleurotus ostreatus	1	[37]
Liquid	Oyster mushroom	Pleurotus spp.	2	[25,38]
	Shiitake	Lentinula edodes	1	[36]
Others (wood pellet, block, and cassava peels)	Oyster mushroom	Pleurotus spp.	2	[7,16]
	Shiitake mushroom	Lentinular squarrolus	1	[7]
	Splitgill mushroom	Schizophyllum commune	1	[24]

). Most of the recent studies used grain spawn supplements with wheat bran, gypsum, and/or calcium carbonate [20,21,22,23]. There were a few studies using stick, sawdust, and liquid spawns in mushroom cultivation. In addition, new types of spawn such as block, wood pallet, or agricultural waste have been developed recently to provide more choices to mushroom growers [7,16,24].

3.2.1. Grain Spawn

Grain spawns can be made using various grains such as wheat, barley, oat, sorghum, millet, and many others [14,31,39,40]. Grains contain sufficient carbohydrates which supply necessary nutrients for mycelium growth [14]. In this review, 45 out of the 56 studies used grain spawn to inoculate into growing substrate. This reflects its wide availability and favourable physical properties [14]. However, this trend may not be universal, as sawdust spawn are predominant in certain regions such as South Korea, depending on local cultivation practices and resource availability. Grain spawn preparation does not require expensive equipment. Grains are boiled and sterilised before inoculating with mushroom mycelium [14,25,31]. Spawn qualities depend on grain types, which is a critical factor for achieving faster mycelium growth, higher mushroom yield, and BE [14]. It was indicated that different grain spawn has influenced spawn running time and the number and weight of the fruiting body, as well as mushroom production [31]. The possible reasons for that would be grain characteristics, as grains work as mycelium carriers, with smaller grains providing a higher number of inoculation points due to their greater surface area [13,41]. However, larger grains contain more nutrients, which can support mycelial growth over a longer period [13,40]. Mushroom spawn performance is species-dependent and each mushroom has its own favourite grain carriers (

Table 2. Preferences of spawn substrate by mushroom species.

Mushroom Species	Spawn Substrate	References
P. ostreatus	Wheat, popcorn, chickpea, mix of wheat, barley, and oat	[39,40,42,43]
P. djamor	Wheat	[42]
P. florida	Rice grain, chickpea, and corn	[41,43]
P. eryngii	Wheat	[29]
P. cystidiosus	Chickpea, corn, and wheat	[43]
L. edodes	Date grain	[44]
H. ulmarius	Pearl millet	[45]
V. volvacea	Sorghum	[31]
G. Lucidum	Wheat	[34]

). The choice of grain types for mushroom spawn depends on their local availability and cost [41].

3.2.2. Sawdust Spawn

Sawdust spawn was the most common spawn used for the mushroom industry in Korea because it is easy to prepare, is low cost, and has minimal equipment requirements [18]. However, despite these advantages, the availability of quality sawdust can be limited in certain regions or under large-scale mushroom production, prompting a growing interest in alternative spawn substrates [16,36]. Various types of sawdust are used for the spawn production of mushrooms, and each mushroom has its own favourite. Broad-leaf trees including eucalyptus, mango, mulberry, poplar, and tooni were utilised to produce the spawn of Lentinula edodes [46,47]. The types of sawdust differently influenced mycelium growth, mushroom yield, and quality [47]. Sawdust is generally poor in nutrients, especially nitrogen. Therefore, supplements such as wheat bran and rice bran were added [36,47]. The preferred sawdust types are different among mushroom species. It was reported that eucalyptus tree (Eucalyptus globulus) sawdust was the best substrate to produce the spawn of Lentinula edodes with shorter mycelium running time and higher rate of mycelium running [46]. For Pleurotus ostreatus, mango (Maggifera indica) and mahogany trees (Swietenia mahagoni) [47] were the best to produce spawn.

3.2.3. Stick Spawn

Stick spawn has been developed as an alternative method for mushroom spawn and has been used to cultivate different mushroom species [37,42]. Sticks for making mushroom spawn can be made from various lignocellulosic solid materials including wood, corn stalk, corn cob, and other plant-based solids [16,37,48]. These materials could be used to make spawn in sticked-shape or blocked/cured-shape spawn. A mixture of sawdust and cereal bran was used to fill the gaps between sticks to enhance mycelium development [37]. Stick spawn has been recorded to have positive effects on mycelium growth and improved mushroom BE [16,37]. As only one stick/block is used to inoculate stick spawn into growing substrate bags [16], it is convenient and less time consuming on inoculation compared to other solid spawns.

3.2.4. Liquid Spawn

Liquid spawn is innovative method for mushroom cultivation in large-scale urban areas where production space is limited and labour is costly [16,49]. Generally, carbohydrate and nitrogen sources, which act as nutrient-rich environments, were used to make growing medium for liquid spawn [38,49]. While sugar and/or starch can be used as suitable carbon sources for mushroom mycelium growing, some nitrogen-rich products including yeast extract, peptone, and in-organic nitrogen are also added to support the protein synthesis of mycelium [38,49]. The benefits of using liquid spawn were indicated in previous studies; however, there are not many studies focusing on this aspect in the last decade, with only three studies using it on oyster mushrooms (Pleurotus spp.) and shiitake mushrooms (L. edodes) [25,36,38].

3.3. The Use of Spawn Types for Mushroom Cultivation

Although spawn types affect mycelium growing, mushroom morphology, and mushroom quality and production [14,31], the type of spawn used for mushroom cultivation depends on the region, mushroom species, sizes of farms, or available technology. For example, sawdust was widely used for the cultivation of Lentinula edodes in Korea [36], while stick spawn was utilised in Pleurotus eryngii cultivation in China [16]. Liquid spawn seems be suitable with large-scale farms in developed regions [16], while grain spawn is more suitable within small-scale farms. The advantages and limitations of the spawn types are summarised in

Table 3. Advantages and disadvantages of spawn types.

Spawn Types	Advantages	Disadvantages	Reference
Solid spawn (grain, stick, sawdust, and other lignocellulosic carriers)	Easy manufacture; Low equipment investment; Highly adaptable; Short lag time; Faster initial colonisation.	Long spawn running time; High risk of contamination; Labour-intensive inoculation.	[18,24,37]
Liquid spawn	Uniform distribution and fast colonisation; Less chance of contamination; Low cost; Automative inoculation; Quick preparation; Less production space requirements.	Expensive equipment; Strictly sterile environment required.	[18,25,49]

.

3.4. Quality Characteristics of Mushroom Spawn

Spawn quality is one of the main factors contributing to successful mushroom cultivation. It is directly related to mushroom yield and its biological efficiency, as high-quality spawn resulted in robust mycelial growth, shorter substrate colonisation, and produced healthy mushroom [14]. There are several factors that affect mushroom spawn quality including the purity of the culture, spawn growing materials for rapid mycelium colonisation, nutrients, and inoculum units, which should be considered to produce high-quality spawn [40]. High-quality is spawn characterised by optimal mycelial growth, vigour, and genetic purity [14]. Spawn with the above characteristics promotes quick and uniform colonisation of the substrate, facilitating effective nutrient uptake during the fruiting stage [50]. Such spawn supports the development of a dense mycelial network, which in turn enhances both the number and size of the fruiting bodies, ultimately leading to improved yields [51]. Moreover, using reliable spawn contributes to consistent crop performance, a key factor for both commercial producers and small-scale growers [14].

There are several factors that affect mushroom spawn quality, such as mushroom strains, purity of the culture, and growing medium [40]. The main criteria to qualify grain spawn is based on colour, odour, and texture [14]. High-quality spawn would be white or light cream-coloured specimens with a mushroomy or earthy odour, without brown, black, and yellow spawns or those with mouldy or sour odours. The texture should be consistent with cotton and be snow-like without any visible sign of contamination such as mould, off-colouring, and foreign sediments. Odour should be pleasant, light, sweet, and mushroomy or earthy. High-quality spawns resulted in faster colonisation, suppressed contamination, and enhanced yield efficiency [14,40,49].

3.5. Mycelium Growth Rate and Spawn Running Time

There are limited studies evaluating the mycelial growth rate of mushroom spawn. Mushroom mycelium growth rates were varied depending on mushroom species, mushroom strain, application methods, and spawn types. A study found that the growth rates of mycelium were significantly different among mushroom strains [25]. Results from this study indicated that the growth rate of liquid spawn was much higher compared to other types of spawn (

Table 4. Mycelium growth rate of mushrooms.

Spawn Types	Base Materials	Mushroom Species	Growth Rate (mm/day)	Replicate (n)	References
Sawdust	Sawdust	P. ostreatus.	6.25 ± 0.16	30	[16]
	Pine sawdust	Sparassis latifolia	1.23 ± 0.09	NR	[49]
Grain	Wheat grain	P. ostretus.	8.60 ± 0.26	3	[25]
	Wheat grain	P. citrinopileatus	8.65 ± 0.26	3	[25]
	Wheat grain	P. columbius	6.20 ± 0.23	3	[25]
Block	Corncob	P. ostreatus.	6.24 ± 0.13	30	[16]
	Sugarcane	P. ostreatus	6.13 ± 0.09	30	[16]
	Loofah	P. ostreatus	6.16 ± 0.12	30	[16]
Liquid	Malt extract, K2HPO4	P. ostreatus.	14.00 ± 0.22	3	[25]
	Malt extract, K2HPO4	P. citrinopileatus	10.25 ± 0.31	3	[25]
	Malt extract, K2HPO4	P. columbinus	9.60 ± 0.28	3	[25]
	Potato, glucose and peptone	Sparassis latifolia	1.69 ± 0.31	NR	[49]

Mycelium growth rate data presented as means ± SD. Abbreviation: NR = not reported.

).

A faster mycelium growing rate will result in a shorter time being required for the full colonisation of mycelium, which is beneficial for mushroom growers. This explains why the use of spawn types has been recorded to influence the spawn running time (the number of days required for the completion of mycelial growth). As the mycelium growth rate in liquid spawn is higher than in grain spawn [25], the spawn running time was shorter [36]. Stick spawn was recorded to reduce the spawn running time (the time from inoculation with spawn to complete mycelial colonisation) in oyster mushrooms (12.22 days), while using block spawn took a longer time to fully colonise the substrate (34–36 days) (

Table 5. Summarisation of spawn running time in mushrooms.

Spawn Types	Mushroom Species	Base-Growing Substrate	Spawn Running Time (Days)	Replicate (n)	References
Stick	P. ostreatus	SD	12.22± 0.75	30	[37]
Grain	P. pulmonarius	WS	10.5 ± 0.18	3	[1]
	P. pulmonarius	SD	50.5 ± 3.50	10	[53]
	P. ostreatus	SS	13 *	3	[22]
	P. ostreatus	SD	36–38 *	4	[21]
	P. eryngii	SS	11.8 *	4	[29]
	P. eryngii	SD	38.74 ± 0.91	3	[52]
	P. eryngii	SD	60 *	4	[21]
	H. erinaceus	CSH	27.4 *	3	[9]
	H. erinaceus	CSH	38.3 *	3	[9]
	L. edodes	WH	43.00 *	3	[8]
	L. edodes	WH + RH	28.67 *	3	[8]
	A. bisporus	WS	22 *	24	[33]
	V. volvacea	CW	7 *	5	[32]
Sawdust	P. ostreatus	CSH	34.38 ± 0.85	3	[16]
Block	P. ostreatus	CSH	36.12 ± 1.25	3	[16]

Spawn running time are presented as mean ± SD/SE; * SD/SE values were not reported. Abbreviations: CSH = cottonseed hull; CW = cotton waste; SD = sawdust; SS = sorghum straw; RH = rice hush; WH = water hyacinth; WS = wheat straw.

). A possible reason could be related to the number of inoculum points. As myceliums develop on the surface of the carriers, a larger-surface spawn substrate carries more mycelium than a smaller one [13,41]. The surface sizes of the blocks are much smaller than the sticks; 1.5 cm³ [16] compared to 12–15 cm in length and 0.8–1 cm in wide [18,37]. Using grain spawn resulted in various spawn running times, varying from 7 to 60 days depending on mushroom species. Spawn running time for the king oyster mushroom took longer than other oyster species in most cases (32–38 days compared to approximately 18–25 days) [8,23,52]. It can be concluded that it is important to choose the type of spawn to optimise mycelium growth and minimise spawn running time, ultimately enhancing mushroom production efficiency.

3.6. Spawn Inoculation Rates

The inoculation rates for mushrooms are inconsistent in terms of units. While the inoculation rates of grain, sawdust, and liquid spawns were calculated based on the percentage of wet weight of growing substrate, the block and stick spawn rates were calculated based on the stick/block sizes. A piece of block spawn (1.5 cm³) or a stick of 15 cm length with a 1 cm width and 2 mm thickness was used to inoculate into a substrate bag [16,37].

Spawn inoculation rates have influenced mushroom morphology and the production of mushrooms, which is directly related to BE. A low level of spawn may not be sufficient to initiate growth, resulting in longer cultivation time and lower BE. In contrast, a higher spawn rate can suppress competing organisms [35], thereby reducing the risk of contamination and increasing yield. However, very high doses of spawn could have no impact on BE, leading to economic loss [35,54]. Our results indicated that most of the recent studies were conducted on oyster mushrooms (Pleurotus spp.). The spawn inoculation rates for Pleurotus spp. cultivation varied from 0.5 to 13% of wet substrate weight, with most study cases using 2–5% (

Table 6. Spawn inoculation rates used in mushroom cultivation.

Spawn Types	Mushroom Species	Spawn Rates (%)	Number of Studies	References
Grain	Pleurotus spp.	0.5–1.9	8	[43,53,54,55]
		2–3	10	[8,17,20,29,56]
		3.1–5	13	[7,14,23,27,35]
		5.1–10	8	[22,25,57,58]
		10.1–15	3	[28,35]
	A. bisporus	0.7	1	[33]
	H. ulmarius	3–5	2	[14,30]
	H. erinacea	3	1	[9]
	G. lucidum	5	1	[34]
	L. edodes	2	1	[8]
	V. volvacea	2–5	2	[30,31]
Sawdust	P. ostreatus	3–5	1	[35]
		5.1–10	1	[35]
		10.1–13	1	[35]
	L. edodes	1.2–2	1	[36]
Liquid	Pleurotus spp.	10	1	[25]
	L. edodes	1.2–2	1	[36]

). The optimum grain spawn that reduced incubation time and increased yield was 2–4% [1,54], while that of sawdust was 9% [35]. Higher rates of spawn (>10%) was recorded to insignificantly increase the BE of oyster mushrooms [35]. There were few studies examining the effect of spawn levels on other mushrooms including Lentinula edodes, Volvariella volvacea, Hericicum erinacea, and Hypsizygus ulmarius. The spawn rates used for these mushrooms were lower, from 1 to 2%. In summary, spawn inoculation rates are different among mushrooms, and inoculum rates for Pleurotus species should not be in excess of 10% as no significant increase in BE is observed.

3.7. Mushroom Characteristic and Yield as Affected by Spawn Types and Rates

The effects of spawn types on mushroom characteristics were studied with different results. Some studies have reported that the spawn-growing medium may influence the morphological characteristics of mushrooms [59]; there are others who claim that spawn types have no effect on mushroom morphology such as cap, gill, and stipe [36].

There is a large variation in the BE of mushroom evident in this review, varying from 5.18 to 173.38% (

Table 7. Summary of mushroom yield and BE based on spawn types and rates.

Spawn Types	Mushroom Species	Spawn Rate (%)	Yield (g/kg Substrate)	BE (%)	References
Grain	Pleurotus spp.	0.5–1.9	84–226	17.95–67.15	[1,52,53]
		2–3	89–575	27–88.5	[8,20,56]
		3.1–5	NR	20–173.38	[7,14,23,27,40,60]
		5.1–10	NR	5.18–159	[22,57,61]
		10.1–15	233–594	NR	[28,35]
	A. bisporus	0.7	NR	58.0–84.98	[33]
	H. ulmarius	3–5	NR	56.73–129.2	[14,30]
	H. erinacea	3–5	77–153	22.3–44.4	[9]
	G. lucidum	5	NR	55.3	[34]
	L. edodes	2	343–533	66–82	[8]
	V. volvacea	2–5	NR	9.42–15.79	[31]
Sawdust	Pleurotus spp.	3–5	154–166	NR	[7,35]
		5.1–10	256–314	NR	[35]
		10.1–13	324–328	NR	[35]
	L. edodes	1.2–2.0	100–240	NR	[36]
Cassava peel	Pleurotus spp.	5	380–706	38–70	[7]
	L. squarroslus	5	354–675	35–67	[7]
Liquid	L. edodes	1.2–2.0	100–330	NR	[36]
	Pleurotus spp.	10	212–261	NR	[25]
Stick/Block	Pleurotus spp.	1–2.4 cm3	235–243	68.65–70.94	[16,37]

The yields (g/kg substrate) were estimated based on the reported yield and wet weight of bags; NR means data not reported.

). This variation is likely influenced by many factors including mushroom species, growing conditions, growing substrate, and many others. Some of the highest BE values (146.01–173.38%) were reported for P. Florida growing on wheat straw supplemented with bran and soybean in a study from India [60]. In contrast, the lowest BE value (5.18%) was recorded for P. ostreatus growing on sorghum stalk in a study from Ethiopia [50]. In the same study, the BE reached 101.2% when P. ostreatus was cultivated on different substrates, highlighting the significant effect of substrate choice on yield. Both types and inoculation rates were recorded to influence mushroom yield by enhancing mycelium growth, fruiting body size, and mushroom yield [25,35,36]. Many studies suggested that the use of a spawn rate of 2–5% resulted in a higher BE [1,35,54]. Although there has not been many studies on liquid spawn in the last decade, it is indicated that liquid spawn produced a better yield of mushroom compared to solid spawn in most cases [25,36]. Using liquid spawn to cultivate shiitake mushroom reduced the spawn running time by 5% compared to sawdust spawn and mushroom production was higher [36]. Overall, liquid spawn tends to outperform solid spawns in both yield and incubation time, although outcomes vary by species and growing conditions.

Although the stick and liquid spawns required shorter incubation times (12–13 days compared to 28–36 days in grain spawn in most studies), the BE remains comparable (68.65–70–94%). This suggests that the spawn’s running period may not reduce yield performance. However, the interactions between spawn running time and yield or BE have not been comprehensively examined in the literature and contradictory findings have been recorded. For instance, a study on shiitake mushrooms showed that longer spawn running times resulted in a greater BE than shorter ones [62], whereas another study on milky mushrooms reported that the highest yield and BE were achieved in a treatment which required the lowest spawn running time [63]. In commercial mushroom cultivation, the spawn-running period is a critical economic factor influencing production efficiency. Prolonged incubation increases the duration that substrate bags must be stored before fruiting, thereby elevating space, energy, and labour costs. Although extended incubation may not compromise BE, it can negatively affect overall production turnover and profitability.

Given the limited data on stick/block and liquid spawn, these findings should be interpreted cautiously. Further research involving multiple strains, substrates, and environmental conditions is required to validate the relationship between incubation duration, substrate colonisation, and yield performance.

4. Limitations of the Study

Although the literature search was conducted on five different databases including Scopus, ScienceDirect, Google Scholar, Web of Science, and CAB abstracts, relevant studies may still exist in unindexed or non-English publications, particularly from regions where mushroom cultivation is active. The review focused on the literature published between 2015 and 2025, which may have excluded earlier studies containing valuable baseline data. The evidence base was dominated by Pleurotus spp., and considerable variation in substrates, spawn types, and cultivation methods among studies restricted direct comparisons. In addition, inconsistent reporting of replication and variability limited the assessment of methodological quality.

5. Conclusions

The diversity of mushroom spawn types is dominated by four main types, including grain, sawdust, stick, and liquid spawns, with emerging types such as wood pellet and cassava peel showing potential for innovation. This review indicated that spawn type significantly influences mushroom yield. Both the type and inoculation rate of spawn significantly influence mycelial growth and mushroom yield. The strongest evidence currently pertains to Pleurotus spp., for which cereal-based and liquid spawns show promising results in terms of colonisation speed and yield performance. However, the evidence base for other genera remains limited, and variations in methodology and reporting standards preclude broad generalisations. Future studies should broaden their focus beyond oysters to include other mushroom species. Despite the inherent limitations in language and database coverage, this review provides an updated synthesis of contemporary research and identifies key knowledge gaps for further investigation in mushroom spawn technology.