How to Grow Mushrooms in Grow Bags: The Complete Guide (2024)

Mushrooms are a delicious and nutritious addition to many dishes. Whether you want to add flavor to soups and stews or make veggie burgers more meaty, mushrooms do the trick. Growing your own mushrooms at home is easier than you think with the help of grow bags. Grow bags provide the perfect contained environment for mushroom cultivation right at home.

In this complete guide, you’ll learn everything you need to know about successfully growing a variety of mushroom varieties of grow bags. We’ll cover choosing the right grow bag size and material, selecting spawn and substrates to fill your bags, maintaining ideal temperature and humidity levels, encouraging mushroom fruiting, harvesting at the right times, troubleshooting common issues, and getting multiple flushes out of your grow bags.

What Is a Mushroom Grow Bag?

A mushroom grow bag is a specially designed bag used to cultivate various types of mushrooms at home or commercially. Grow bags create the perfect microclimate and growing conditions for mushroom mycelium to colonize and fruit.

Grow bags are constructed from materials like plastic, burlap, or other breathable fabrics. The bags feature filtration patches that allow for gas exchange while preventing contamination from entering. The top of the bag remains open, allowing you to easily fill and access the mushroom substrate inside.

Typical grow bags used by home cultivators’ range in size from 5 to 50 liters. Bags designed for commercial cultivation can be much larger. The bags feature grommets along the top and sides to secure the bag after filling and to attach ropes for hanging vertically.

When preparing to use a mushroom grow bag, you first fill it with a nutritious substrate like wood chips, sawdust, straw or a specific mushroom compost. You then introduce mushroom mycelium by using grain spawn or a mushroom grow kit. This allows the mycelium to colonize through the substrate inside the bag. From there, mushrooms begin forming either inside or along the surface of the bag.

Compared to other home mushroom growing methods, bags offer a versatile, simplified option. The all-in-one nature makes grow bags a great choice for beginners while providing flexibility for larger scale cultivation.

How do Mushroom Grow Bags Work?

Mushroom grow bags provide the ideal microenvironment for mushroom cultivation. The bags allow you to combine a nutritious growing medium with mushroom spawn in a portable, breathable container. This kicks off the natural life cycle process mushrooms need to develop from spores into mature fungi.

The mushroom growth process starts when mycelium from spores or spawn begins breaking down and consuming the nutrients within the bag’s substrate. As the mycelium spreads, it forms a dense, web-like matrix, allowing mushrooms to start budding and fruiting along the surface.

The breathable fabric and filtration patches along the bags provide the ideal level of fresh air exchange. This gives the fast-growing mycelium enough oxygen while retaining the high humidity mushrooms require. The open-top of the bag lets you easily monitor conditions and initiate fruiting by providing additional air exchange.

Mushroom grow bags feature structures like grommets and rope handles at the sides and top. This allows you to securely seal then hang the bags vertically, so mushrooms can grow upward against gravity. The vertical orientation promotes proper moisture distribution and prevents pooling at the base as the mushrooms mature.

As the first flush of mushrooms are harvested from the initial colonization, the nutrients remain, allowing further flushes. Simply soak the bag to rehydrate it and within a week or two, new mushrooms form. This cycle repeats several times until the substrate is fully colonized and depleted.

The Benefits of Growing Mushrooms in Bags

Using grow bags for mushroom cultivation offers numerous advantages over other growing methods. Compared to more complex set-ups, these bags provide the flexibility and convenience home cultivators look for, while reducing costs, maintenance and waste. Let’s discuss three key benefits grow bags offer:

• Ease of manipulation. Grow bags allow you to easily handle, place and transport mushrooms during various phases of growth. Customizable clips, ties and grommets built into the bags let you alter environmental factors like air exchange, moisture, sunlight exposure and temperature. Bags also disperse growth over a larger area, requiring less intensive space than other techniques.
• Inexpensive and disposable. Cultivating mushrooms in grow bags is very economical. An entire set-up can cost under $20 per bag and last for several flush cycles. The all-in-one nature of grow bags means no land or dedicated mushroom house is required. For small or large scale cultivation alike, grow bags offer an affordable, renewable way to maximize production.
• Allows adjustment of size and shape. Mushroom grow bags come in a wide range of sizes from under 1 liter to over 150 liters to suit personal and commercial demands. The expandable fabric also means you can squeeze in additional substrate to bolster yields. You can shape shorter, wider bags or tall, pillar-like cylinders based on your space and stacking system.
• Easy observation of growth. The transparent and breathable fabric used for most mushroom grow bags allows for easy visual monitoring as mycelium colonizes and mushrooms begin to form. You don’t need to open or disrupt the bags to check progress. The visibility helps troubleshoot issues like contamination early on.
• Durable for sterilization processes. Mushroom grow bags are designed to withstand pasteurization or sterilization before introducing mushroom spawn. The durable plastic polymers, thickness gauge and double stitching allow bags to be briefly subjected to hot water or steam processes for substrate preparation. This eliminates competing bacteria and molds without compromising bag integrity for subsequent cultivation.

Different Types of Mushroom Grow Bags

Mushroom grow bags come in a wide selection of shapes, sizes, and materials to meet the needs of home cultivators and commercial growers alike. When selecting a mushroom bag, key considerations include breathability, durability, and how the bag’s specific properties influence the preferred growing environment for your mushroom type.

Basic mushroom grow bags feature exterior fabrics like polypropylene or flexible plastics that resist tearing while allowing for gas exchange. More advanced grow bags may consist of burlap or coconut fiber surroundings that promote greater air flow. These natural fiber bags provide superb breathability, while plastic-based bags offer maximum durability for sterilization and reuse.

Another differentiation among mushroom bags is their micron filtration patch. This regulates microscopic air exchange to prevent contamination while satisfying the respiration needs of fast colonizing mycelium. Denser filters around 0.2 microns are ideal for beginners, while more advanced cultivators often opt for bags with 1.0-micron patches to avoid restricting growth.

In addition to fabric and filtration differences, mushroom grow bags vary significantly in size and shape. Short squat bags around 20 liters are common among home growers, while tall cylindrical bags up to 150 liters are used on an industrial scale. Commercial bags also utilize heavy plastic composites and double stitching to support tremendous weights when stacked.

No matter the exact specifications, most mushroom bags utilize grommets, rope handles and adjustable closures along the top opening. This allows the bags to be securely sealed, then hung vertically for ideal mushroom formation. Understanding these core commonalities and differences will ensure you select the right mushroom grow bag for the species you want to cultivate.

Step-by-Step Guide to Using a Mushroom Grow Bag

Thriving mushroom grow bags depend on mastering some key steps including connecting all the necessary components, providing ample conditions for colonization and fruiting, and maintaining the ongoing care that preferential mushroom species demand.

While individual techniques may vary slightly by mushroom type and cultivation environment, there’s a comprehensive methodology you can follow to ensure successful harvesting from your mushroom grow bags.

Gather Necessary Supplies

Getting your mushroom grow bags ready starts with assembling the right supplies and materials. You’ll need an assembled grow bag matched to the size of your growing operation and mushroom type. Select substrates like wood chips, manure or straw that provide nutrients. Purchase mushroom grain spawn or retrieve a tissue sample for the gourmet or medicinal species you wish to grow.

You’ll also want to prepare your growing space by optimizing temperature, airflow and lighting conditions. Research recommendations for your mushroom variety and adjust as needed. Dialing in these elements takes some tweaking but drastically boosts your long-term outcomes.

Prepare the Bags

Once supplies are gathered, it’s time to fill your mushroom grow bags. Start by moistening the substrate ingredients, like straw, according to instructions. Evenly pack the moistened material into the bags, distributing evenly from top to bottom. Leave at least 5 inches of space along the top. This allows room for fully colonizing and fruiting overhead.

Next, carefully crumble the mushroom grain spawn over the substrate, aiming for dispersed coverage, so pockets don’t remain uncolonized. Using a ruler, gently mix the grain spawn down through the middle section of the substrate to initiate expansion both upward and downward through the bag. Don’t overmix or pack too firmly. Some aeration and fluffiness aids thorough colonization after sealing.

Seal the Mushroom Grow Bags

After inoculating your bags with spawn, securely seal them, allowing only the filtration patch to permit gas exchange. Use rope handles, metal clips or plastic ties to firmly close the opening while still permitting airflow. Attach an identification tag listing the species, date and batch number.

Moving delicately, position the tight-sealed bags oriented vertically according to your growing set up and recommended fruiting needs. Logging details on lighting, humidity and other factors provides helpful data when mushroom pins emerge. With preparation complete, vigorous mycelial growth will soon commence!

Incubate the Mushroom Grow Bags

Now when your grow bags are filled, spawned, and sealed, incubation begins. This phase allows the mycelium to rapidly spread, bonding intimately with the surrounding substrate. Place bags in complete darkness at around 75°F, the ideal temperature for colonization.

Avoid direct exposure to light and refrain from disturbing the bags during this period. The incubation process usually takes 2–4 weeks depending on factors like moisture, aeration and strain aggressiveness. Misting bags and airflow should be minimal at first but can increase as colonization progresses to avoid overly dry or carbon dioxide saturated conditions.

Trigger Your Mushrooms to Start Fruiting

As the mycelium fully permeates the substrate, colonization tapers off, transitioning the growth cycle toward mushroom fruiting. Reduction of carbon dioxide buildup coupled with exposure to light and cooler temperatures help trigger this shift. Allow more air exchange by widening bag openings while moving them to a brightly lit area around 65°F.

Lightly mist the blocks and drain excess moisture. Within a week tiny mushroom pins should stud the mycelium, rapidly enlarging over several days. Harvesting ideally takes place just before veil break when caps remain round and intact.

Harvest the Mushrooms

Timely harvesting preserves quality and reinforces future production capacity. As mushrooms reach maturity, use a sharp knife to cut through the stem base while carefully twisting away from the block. Rapidly repeat harvesting as additional clusters mature, aiming for several pickings through the first heavy flush.

During peak cropping, daily harvesting prevents over-maturation and rotting. Schedule picking times for early morning when mushrooms cells are plump. After cutting, gently trim away the stub, leaving the mycelium undamaged to support further flushes.

Consider to Create a Fruiting Chamber

Constructing an enclosed fruiting chamber provides maximum control over environmental triggers prompting mushroom production from your grow bags.

Converted cabinets, small rooms or even basic plastic containers can all serve as functional fruiting chambers. The chamber allows you to dial in lighting duration, air exchange, humidity and temperature levels that signal to your mushroom mycelium it’s time to pin and fruit.

This takes experimentation but helps stabilize seasonal outdoor fluctuations. For continuous harvesting, a controlled fruiting room really optimizes your mushroom yields.

Common Issues with Mushroom Grow Bags

While mushroom grow bags offer a relatively straightforward cultivation method, problems can arise that compromise yields and quality. Being aware of these common pitfalls allows growers to swiftly address concerns before they escalate.

Unwanted mold, bacteria and fungi competing with mushroom mycelium ranks among the most widespread problems mushroom growers face. Inspect bags daily during colonization and fruiting periods for powdery discolorations, foul odors and unnatural appearances signaling contamination. Isolate and dispose of compromised bags swiftly to avoid site-wide spread. Boosting air circulation, sterilizing between substrate batches and selectivity when opening bags helps prevent contamination.

Humidity falling substantially below 65% during pinning and fruiting dramatically slows growth and causes mushroom deformation. Increase humidity by sealing more of the bag, moving them to a fruiting chamber or placing them over trays of moistened perlite. Just ensure no standing water contacts bags directly, leading to bacteria concerns. Boosting room humidifier levels can help as well.

Mushrooms demand lofty air exchange, or FAE, levels reaching eight complete room air replacements per hour. Inadequate fresh airflow stunts mushrooms and thickens stems as they struggle to respire. Opening more of the grow bag’s upper portion and fanning several times daily moderates this. Hanging bags to maximize surface area exposed also amplifies gas exchange.

Substrate moisture evaporating too rapidly by the second flush onward leaves mycelium stunted with few nutrients to generate new mushrooms. Placing drainage trays under bags catching excess “drip” helps retain substrate moisture. Misting the blocks directly should only be done immediately following a flush. For the best re-wetting, fully submerge older blocks in non-chlorinated water for 12 hours maximum before returning the revived bags to fruiting conditions.

By closely examining environmental factors, identifying issues early and making appropriate adjustments, mushroom growers can sidestep common bag cultivation headaches. This keeps your harvesting rolling flush after bountiful flush.

Frequently Asked Questions