Growing mushrooms in a grow bag is one of the easiest and most effective ways to cultivate them at home.

When I first heard about it, I wasn’t sure it would work as well as some other methods, but after giving it a try, I was amazed at how simple it made the whole process.

Whether you’re a complete beginner or just looking for a hassle-free way to grow mushrooms, a grow bag might be the perfect solution for you.

Why Use a Grow Bag for Mushrooms?

I’ll be honest—when I started growing mushrooms, I was a little overwhelmed by all the different methods.

Logs, containers, substrates—it was a lot to take in.

That’s why I turned to grow bags.

They simplify the process while still giving you control over the environment.

The bag acts like a mini greenhouse, providing the perfect mix of moisture and air circulation for your mushrooms to thrive.

Plus, grow bags are portable, sterile, and ideal for small spaces.

Whether you want to grow them on a windowsill or in a dark closet, grow bags fit pretty much anywhere.

You don’t need a big setup, which made it super convenient for me when I was just starting out.

What You’ll Need to Get Started

Before we dive into the steps, here’s a list of everything you’ll need. I like to have everything laid out before I start, so I’m not scrambling to find tools halfway through the process.

• Mushroom spawn (oyster, shiitake, or button mushrooms are great for grow bags)
• Sterile substrate (straw, sawdust, or coffee grounds work well)
• Grow bag (make sure it has a filter patch for air exchange)
• Spray bottle (for maintaining moisture inside the bag)
• Sterile gloves (to prevent contamination)

Step-by-Step Guide to Growing Mushrooms in a Grow Bag

Step 1: Preparing the Substrate

The substrate is the food your mushrooms will grow in, and it’s crucial to get this right.

For grow bags, I usually go with pasteurized straw or sawdust.

It’s important to pasteurize the substrate to kill off any bacteria or unwanted mold, which can easily contaminate your mushrooms.

If you’re using coffee grounds, make sure they’re freshly brewed and cooled down before adding them to the grow bag. It’s a fun, eco-friendly option, and mushrooms love the nutrient boost.

Step 2: Filling the Grow Bag

Once the substrate is prepared, it’s time to fill the grow bag.

This step is pretty straightforward—just add the substrate to the bag, leaving a bit of space at the top.

After that, sprinkle the mushroom spawn evenly over the substrate.

You don’t need much spawn to get things going; a little goes a long way.

One thing I found helpful was gently shaking the bag once the spawn is added to distribute it evenly.

This ensures that the mushrooms will grow uniformly throughout the bag.

Step 3: Sealing the Bag and Incubation

Seal the grow bag tightly, but make sure the filter patch is exposed to allow for air exchange.

The next step is placing the bag in a warm, dark area where the mycelium can grow and colonize the substrate.

I usually aim for a temperature between 21°C and 27°C (70°F to 80°F).

Now comes the waiting game.

Over the next couple of weeks, you’ll see white mycelium begin to spread through the substrate.
It’s a fascinating process to watch—kind of like nature’s own slow-motion magic.

Step 4: Introducing Fresh Air and Light

Once the substrate is fully colonized (usually in about 2-3 weeks), it’s time to introduce fresh air and light to stimulate mushroom fruiting.

I cut small slits into the grow bag to allow the mushrooms to start growing out.

It’s best to place the bag somewhere with indirect light.

Mushrooms don’t need much light to grow, but they do need some to trigger fruiting.
I kept mine near a window with diffused sunlight, and it worked perfectly.

Step 5: Maintaining Humidity

Mushrooms love humidity, so keeping the bag moist is key to their growth.

I misted the inside of the bag with a spray bottle every day to maintain high humidity levels.
Just be careful not to over-saturate the substrate—it should be damp, not soaking wet.

If your home is particularly dry, you can create a mini humidity tent by placing a loose plastic cover over the bag. This traps moisture while still allowing airflow.

Our you can buy a grow tent that makes it easier to control the environment.

Step 6: Harvesting the Mushrooms

After about a week or two, you’ll start seeing small mushroom pins form at the slits in the bag.
They grow quickly, so keep an eye on them!

Once the mushrooms have fully developed and the caps begin to flatten out, they’re ready for harvest.

Harvesting is easy—just twist the mushrooms gently at the base and pull them away from the substrate. I found it’s best to harvest them just before the caps fully open to capture the freshest flavor.

Common Challenges and Solutions

One challenge I faced when growing mushrooms in grow bags was managing humidity.
It’s easy to either under-mist or over-mist, and both can cause issues.

My advice is to check the substrate daily—if it feels dry, give it a light mist, and if it looks too wet, cut back on watering.

Another potential issue is contamination, which can occur if the grow bag isn’t properly sealed or if unsterilized tools are used. Always use clean tools and wash your hands before handling anything that comes in contact with the substrate.

My Final Thoughts

Growing mushrooms in a grow bag is one of the simplest ways to get started, especially if you’re short on space or just want an easy method that doesn’t require a ton of equipment.

It’s fun to watch the mushrooms grow and even more rewarding when you get to harvest them fresh for your meals.

If you’ve never grown mushrooms before, I highly recommend trying the grow bag method.
It’s practically foolproof, and you’ll be amazed at how quickly you can enjoy fresh, homegrown mushrooms.

Have you ever thought about trying it yourself? Trust me, once you get started, you’ll be hooked!