In the world of mushroom cultivation, the choice between grain spawn, sawdust spawn, and plug spawn serves as a pivotal decision for cultivators aiming to grow bountiful crops of edible and medicinal fungi. Each kind of spawn possesses unique attributes that cater to distinct cultivation strategies, spawn run time, and price points. Understanding what they are and how each is used unveils a landscape full of possibilities; each presenting its own set of advantages and ideal use cases. In this article we will identify the components and uses for sawdust, grain, and plug spawn and break down how each fits into the mushroom cultivation process, both indoors and outside.
What is spawn?
Mushroom cultivation is full of terminology, and knowing the difference between important terms like spores and spawn is key to getting started. Recall from fungal biology that fungi begin their life as spores; microscopic cells containing half the necessary amount of genetic material to make a new mushroom. In nature, two spores of the same type of fungi must land near each other and fuse to form a mycelium; the vegetative, growing body of the fungi. In a commercial setting, spores or mycelium from a known mushroom variety are cultured in a lab and transferred to bags of hydrated, sterilized grain, an inexpensive and nutritious substrate for mushroom cultivation. Once the mycelial tissue or spores begin growing on the grain, it becomes grain spawn, which can then be combined with a variety of bulk substrates for use in different applications and growing methods.
What are the different kinds of spawn?
Spawn comes in different forms, depending on its application, and includes grain spawn, sawdust spawn and plug spawn. As its name implies, grain spawn is composed of grains sourced from the agricultural byproducts industry and can include millet, oats, rye, wheat, sorghum, popcorn, brown rice and even birdseed. While highly nutritious, mushroom yields from grain spawn alone are low. Therefore, grain spawn is combined with bulk substrates to make a variety of products including fruiting blocks, spray and grow kits, sawdust spawn and plug spawn. Sawdust spawn is a small amount of grain spawn combined with hydrated hardwood sawdust and is ideal for log cultivation and growing in garden beds, as well as the pillar method of log cultivation. Plug spawn is a small amount of grain spawn grown onto hardwood dowels and used in log cultivation outdoors with species like shiitake and lion’s mane. For plug spawn, you’ll need to select the right log for the right project. Our log growing kits that include the tools you’ll need to get started on log projects.
Sawdust spawn
Grain spawn
Plug spawn
What is the difference between grain spawn and sawdust spawn and when would I use one over the other?
As a reminder, grain spawn is a hydrated mixture of grains like millet and rye, while sawdust spawn is composed of hydrated hardwood pellets plus supplement additives like gypsum, wheat bran, and coco coir for added nitrogen and water retention. Choosing between the two comes down to your specific project and balancing expense, contamination risk, and desired yield. While more expensive and nutritious, grain spawn is more prone to contamination than sawdust spawn, but can be used indoors to make more grain spawn bags as well as fruiting blocks, sawdust spawn, and plug spawn. Due to its larger particle size, grain spawn has a slower spawn run time than sawdust spawn, meaning it will take longer to colonize its substrate. In an outdoor setting, grain spawn can be combined with a variety of substrates including straw or woodchips for use in garden beds, buckets, and containers. Grain spawn is not recommended for log cultivation, however. Sawdust spawn is best used in larger log projects that call for the traditional “drill and fill'' cultivation method as well as with the pillar method and in garden beds. Both sawdust and grain spawn can be used to make outdoor beds, but sawdust spawn is recommended in garden beds as grain is more susceptible to contamination and predation than sawdust.
Strain selection
Just as farmers took the wild cabbage and turned it into popular modern cultivars like broccoli, cauliflower, and kale, mushroom growers select for different traits and have, over time, developed strains for use in different applications. For instance, North Spore has a strain of shiitake spawn that is best suited for growing indoors in grow rooms in addition to a strain best suited for outdoor cultivation on logs. Some strains are better adapted for different types of spawn, too. This means that the strains used in sawdust spawn and plug spawn are often different from those used in grain spawn. For example, the outdoor strains might be selected more for their ability to handle temperature fluctuations in a log or garden, while the indoor strains may be chosen more for resistance to contamination growing in a substrate block or all-in-one bag.
When selecting your spawn, make sure to choose a strain that matches the application, allowing you to cultivate the right strain for the job, be it indoors or outside.
Final thoughts
Choosing between sawdust, grain, and plug spawn is dependent on your specific project needs, your species of preference, and what substrates and growing methods are available to you. Grain spawn, composed of hydrated grains like millet and rye, is recommended for indoor cultivation and, for some specific species, adaptable to various outdoor methods including gardens and outdoor beds. Sawdust spawn, formulated from supplemented hardwood sawdust, is recommended for large log inoculation projects as well as, for some specific species, gardens and outdoor beds. Plug spawn has a narrower application and is recommended for use in log cultivation only. With the right supplies and care, your efforts will be rewarded with a supply of fresh homegrown mushrooms, and the knowledge that your cultivation skills are advancing over time. If you have any questions, please reach out! We are here to support you on your mushroom growing journey!