Your Cool Home is supported by its readers. Please assume all links are affiliate links. If you purchase something from one of our links, we make a small commission from Amazon. Thank you!
You can grow mushrooms indoors easily with the right setup, and it’s a rewarding hobby that gives you fresh, tasty harvests year-round.
Learning how to grow mushroom indoors isn’t complicated, and once you understand the basics, you’ll wonder why you didn’t start sooner.
Whether you’re a total beginner or a seasoned gardener, growing mushrooms indoors is a fun experiment that requires minimal space and effort.
In this post, we’ll walk you through how to grow mushroom indoors step by step, covering the supplies you need, the best species for beginners, and common pitfalls to avoid.
Let’s dive into the wonderful world of indoor mushroom cultivation.
How to Grow Mushroom Indoors: The Core Steps
When you think about how to grow mushroom indoors, the process boils down to creating the right environment for mycelium to thrive.
The mycelium is the vegetative part of the fungus, and it spreads through a substrate, which is the food source for your mushrooms.
Once the mycelium colonizes the substrate, you trigger fruiting by changing humidity, light, and fresh air.
This is the basic science behind how to grow mushroom indoors, and it’s simpler than you might imagine.
1. Choose the Right Mushroom Species
The first decision in learning how to grow mushroom indoors is picking the species that matches your experience level and available space.
Oyster mushrooms are the classic choice for beginners because they grow fast and are forgiving of small mistakes.
Shiitake mushrooms are another great option, and they prefer a hardwood substrate like oak or maple sawdust.
If you’re working with a tiny closet or even a countertop, lion’s mane mushrooms also grow well indoors and produce beautiful, fluffy clusters.
For your very first attempt at how to grow mushroom indoors, start with oyster mushrooms and build up your confidence.
2. Gather Your Supplies and Substrate
To grow mushroom indoors, you’ll need a few key supplies, but nothing too fancy or expensive.
You’ll want a growing container like a plastic bin, a spray bottle for misting, and a clean, draft-free area.
The substrate is the real star here, and common options include straw, sawdust, coffee grounds, or even cardboard.
You can buy pre-sterilized grow kits that come with the substrate and spawn already mixed, which makes learning how to grow mushroom indoors even easier.
If you’re going the DIY route, pasteurize your substrate by soaking it in hot water (around 160°F) to kill off competing molds.
Properly prepared substrate gives your mushrooms a clean food source and reduces the risk of contamination.
3. Inoculate and Let the Mycelium Colonize
Once your substrate is ready, it’s time to mix in the spawn, which is basically mushroom seeds or starter culture.
Combine the spawn evenly throughout the substrate, and then pack it into your container or grow bag.
Keep this mixture in a warm, dark place, around 70–75°F, and wait for the mycelium to spread.
This colonization phase usually takes one to three weeks, depending on the species and temperature.
During this stage of how to grow mushroom indoors, don’t open the container too often because you might introduce contaminants.
You’ll know colonization is complete when the substrate is white and fully covered with weblike mycelium.
4. Trigger Fruiting with Fresh Air and Humidity
After colonization, the magic happens, and this is where you really learn how to grow mushroom indoors successfully.
Move your container to a spot with indirect light, like near a north-facing window or under a fluorescent lamp.
Mushrooms don’t need direct sunlight, but they do need a bit of light to know it’s time to produce fruit.
Increase humidity by misting the inside of the container twice a day with clean water.
You also need fresh air exchange, so crack the lid slightly or fan the container a couple of times daily.
This combination of high humidity, fresh air, and light signals the mycelium to form pinheads, which are tiny baby mushrooms.
Within a few days, these pinheads will grow into full-sized mushrooms ready for harvest.
Common Mistakes When You Grow Mushroom Indoors
Even with the best intentions, you’ll hit a few snags when you grow mushroom indoors, but most issues have simple fixes.
Contamination is the biggest enemy, so always wash your hands and sanitize your tools before touching the substrate.
If you see green or black mold growing, remove that section immediately and keep an eye on the rest.
Another common mistake is overwatering, which causes the substrate to become soggy and drown the mycelium.
Mist lightly rather than soaking, and always use clean, filtered water to avoid introducing chlorine or other chemicals.
Finally, don’t give up if your first harvest is small, because growing mushrooms indoors takes a bit of trial and error.
1. Maintaining Proper Temperature and Humidity
Consistent temperature is critical when you grow mushroom indoors, and most species prefer between 60–75°F.
Extreme heat or cold can stall growth entirely, so monitor your environment closely over the fruiting period.
Humidity should stay around 85–95% while fruiting, and a simple hygrometer can help you track this.
If your space is too dry, consider using a small humidifier or placing a wet towel near the growing container.
On the flip side, if you see water pooling on the substrate, add more ventilation to dry things out a bit.
2. Lighting Requirements for Indoor Mushrooms
When you set out to grow mushroom indoors, remember that they don’t need intense light to develop properly.
Natural ambient light from a window is usually enough, and you can also use a simple LED grow light on a timer.
Expose your mushrooms to about 12 hours of light per day, and then let them rest in darkness for the other 12.
Light signals the mushrooms which direction to grow, so it’s important for getting nice, straight caps.
Just avoid direct sunlight because it can dry out the substrate and raise the temperature too much.
3. Harvesting and Storing Your Indoor Mushrooms
Knowing when to harvest is part of mastering how to grow mushroom indoors, and timing matters for flavor and texture.
Harvest your mushrooms just before the caps flatten out fully, as this is when they’re at peak freshness.
Use a sharp knife to cut the mushrooms at the base rather than pulling them, which can disturb the substrate.
After harvesting, you can store the mushrooms in a paper bag in the fridge for up to a week.
You might even get a second flush of mushrooms from the same substrate if you keep up the misting and fresh air.
Every flush teaches you more about how to grow mushroom indoors, so enjoy the learning curve.
So, How Do You Grow Mushroom Indoors Successfully?
You can grow mushroom indoors successfully by following these simple steps and staying patient through the process.
Start with oyster mushrooms, prepare your substrate well, and maintain high humidity with fresh air exchange.
Avoid contamination by keeping everything clean, and monitor temperature and light to encourage healthy fruiting.
Growing mushrooms indoors is a forgiving hobby, and each attempt makes you more skilled at reading your crop.
So grab a grow kit or some spawn, find a small corner of your home, and start your indoor mushroom journey tonight.
With a little practice, you’ll be harvesting fresh, delicious mushrooms that beat anything from the store.