How to Grow Mushrooms at Home Indoors: Oyster, Shiitake & Button

You don’t need a forest or a garden to grow fresh, gourmet mushrooms. With the right method to grow mushrooms at home indoors, you can harvest your own oyster, shiitake, or button mushrooms in just 2–4 weeks—using recycled coffee grounds, straw, or a simple kit. As an urban horticulturist who’s grown mushrooms in a Paris studio for years, I’ve tested every approach. These proven, organic methods work even in windowless kitchens, with no soil, no sunlight, and no special equipment.

• Why Grow Mushrooms Indoors?
• Best Mushrooms for Beginners
• Step-by-Step: Grow Oyster Mushrooms on Coffee Grounds
• How to Grow Shiitake on Hardwood Logs (Indoor Method)
• Button Mushrooms: The Compost Method
• Care Tips for Healthy Fruiting
• FAQ: Your Questions Answered

Why Grow Mushrooms Indoors?

Mushrooms aren’t plants—they’re fungi. And that means they don’t need sunlight, soil, or even green thumbs. They thrive in cool, dark, humid spaces—like closets, basements, or kitchen corners.

Benefits of growing mushrooms at home:

• Zero waste: Use spent coffee grounds, cardboard, or straw.
• Fast results: First harvest in 2–4 weeks.
• Organic & local: No pesticides, no food miles.
• Educational: Perfect for kids, schools, and curious adults.

According to the University of Minnesota Extension, oyster mushrooms are the easiest for beginners—and among the most nutritious, rich in protein, B vitamins, and antioxidants.

Best Mushrooms for Beginners

1. Oyster Mushrooms (Pleurotus ostreatus)

Why it works: Grows on almost anything—coffee, straw, cardboard.
Time to harvest: 2–3 weeks after inoculation.
Flavor: Mild, slightly sweet, meaty texture.
Best for: First-time growers. Very forgiving.

2. Shiitake (Lentinula edodes)

Why it works: Grows on hardwood logs or sawdust blocks.
Time to harvest: 6–12 months (longer but rewarding).
Flavor: Earthy, umami-rich—perfect for soups and stir-fries.
Best for: Patient growers with space for logs.

3. Button Mushrooms (Agaricus bisporus)

Why it works: Grows in composted manure or straw.
Time to harvest: 4–6 weeks.
Flavor: Classic, mild, versatile.
Best for: Those with access to compost or mushroom kits.

Step-by-Step: Grow Oyster Mushrooms on Coffee Grounds

This method uses waste to create gourmet food—perfect for urban dwellers.

What You Need

• 1 liter of used coffee grounds (cooled, from 2–3 days of brewing)
• 100g of oyster mushroom spawn (buy online or from a mycology supplier)
• A clean plastic bag or container with a lid
• Spray bottle with water

Step-by-Step

1. Pasteurize the coffee grounds: Pour boiling water over them, let sit 1 hour, then drain. This kills competing molds.
2. Mix with spawn: In a clean bowl, combine cooled coffee grounds and mushroom spawn.
3. Transfer to bag: Place mixture in a plastic bag. Seal loosely or poke small air holes.
4. Incubate in the dark: Keep at 20–24°C (68–75°F) for 2–3 weeks. Mycelium will turn the bag white.
5. Trigger fruiting: Cut a 5cm hole in the bag. Place in indirect light (not direct sun).
6. Mist 2x daily: Spray the hole with water to maintain humidity.
7. Harvest in 5–10 days: When caps flatten but before edges curl up.

Pro tip: Use organic coffee—non-organic may contain fungicides that kill the mycelium.

How to Grow Shiitake on Hardwood Logs (Indoor Method)

Yes, you can grow shiitake indoors—even in an apartment.

1. Buy pre-inoculated shiitake logs (oak or beech, 3–4 ft long).
2. Soak in cold water for 24 hours every 8–10 weeks to trigger fruiting.
3. Place in a cool, humid spot (bathroom or closet works well).
4. Wait 1–2 weeks for mushrooms to appear.
5. Harvest when caps are rounded but not flat.

One log can produce for 2–3 years—up to 4 flushes per year.

Button Mushrooms: The Compost Method

Button mushrooms need a nitrogen-rich substrate.

1. Use a mushroom kit or make your own with pasteurized compost + straw.
2. Inoculate with spawn and incubate at 24°C (75°F) for 3 weeks.
3. Top with casing layer (peat moss + lime).
4. Keep at 16°C (60°F) with high humidity.
5. Harvest in 4–6 weeks.

Learn how to make indoor compost for your mushroom substrate.

Care Tips for Healthy Fruiting

Mushrooms are 90% water—humidity is everything.

1. Mist 2x daily: Use distilled or filtered water to avoid chlorine.
2. Never let dry out: Cracking substrate = no mushrooms.
3. Avoid direct sunlight: Causes drying and heat stress.
4. Ensure fresh air exchange: Open a window or fan briefly daily.
5. Harvest at the right time: Before caps fully open for best flavor.

See our guide to soil-free gardening for more no-dirt growing methods.

FAQ: Your Questions Answered

Q: Do mushrooms need light?
A: Only for fruiting—indirect light is enough. Incubation happens in total darkness.

Q: Can I use any coffee grounds?
A: Yes—but organic is best. Avoid flavored or oily grounds.

Q: Are homegrown mushrooms safe?
A: Yes—if you use clean spawn and pasteurized substrate. Never forage wild molds.

Q: How many harvests can I get?
A: Oyster: 2–3 flushes. Shiitake log: 4–8 over 2 years.

Q: Can I grow mushrooms in a windowless room?
A: Yes! They don’t need sunlight—just humidity and fresh air.

Q: What if I see green or black mold?
A: Discard the batch. It means contamination—sterilize better next time.

Growing mushrooms isn’t just about food—it’s about transformation. You take waste—coffee, straw, cardboard—and turn it into something alive, nourishing, and beautiful. In a world of consumption, this is creation.

If this guide inspired you to try mycology, share it with a fellow urban forager. And tell us: which mushroom will you grow first?