Mushrooms are a delicious and nutritious addition to any diet. Growing your own mushrooms outdoors is an easy and rewarding gardening project. With a few simple materials and following proper mushroom growing techniques, you can grow a bountiful harvest right in your own backyard.
An Introduction to Growing Mushrooms Outdoors
Outdoor mushroom growing has many advantages over indoor cultivation. The natural daylight, airflow and ambient temperatures of an outdoor environment are ideal for mushroom growth. This makes it simpler for beginners to achieve success without the need for grow lights, humidity controllers or heating elements.
Growing outdoors also allows for larger yield potential in terms of both growth rate and total harvest size. The wider space facilitates larger numbers of mushroom beds or logs. With the right setup, you can harvest several pounds of fresh mushrooms per season.
The key requirements for outdoor mushroom cultivation include:
- A shady spot in the garden with indirect sunlight
- A substrate material such as wood chips, logs or straw
- Mushroom spawn specific to the substrate and species
- Consistent moisture levels in the substrate
- Protection from heavy winds and rain
Proper preparation and care is necessary for a thriving outdoor mushroom patch. But the natural conditions of an outside setting make mushroom growing more hands-off than indoor methods.
Choose the Best Location for Growing Outdoors
When scouting the optimal location to grow mushrooms, consider these factors:
- Shade – Mushrooms need indirect sunlight or dappled shade. Avoid areas with direct sun exposure for the majority of the day.
- Moisture – Prevent the substrate drying out by choosing a naturally damp area or positioning it in shade under trees.
- Air Circulation – Some airflow is beneficial but avoid overly windy spots that can dry out the beds.
- Accessibility – Pick an area you pass by often to easily maintain and monitor the mushroom patch.
- Soil – Good soil drainage is key. Wet, compacted or clay-heavy soil allows waterlogging.
- Space – There should be enough room for the chosen substrate size and future expansion.
Partial sun or light shade under trees like oaks, elms and birches is an excellent environment. Position the mushroom beds alongside sheds, fences or shrubbery to provide wind protection.
Choose the Best Substrate and Mushroom Species
Mushroom species have adapted to thrive on particular substrate materials in their natural environment. Replicating these growth conditions is vital for the best yield.
For woody/organic substrates:
- Oyster mushrooms – Grow on logs or straw. Require pasteurization.
- Lion’s mane – Prefers hardwood logs like oak and alder.
- Winecap stropharia – Thrives on wood chip beds. Chips need pre-treatment.
- Reishi – Grows successfully on oak and maple logs outdoors.
For composted manure substrates:
- Button mushrooms – Produce well in composted manure beds.
- Portobello – Grow best in soil with compost/manure. Need some shade.
- Shiitake – Can adapt to supplemented sawdust or straw substrates.
Always match the mushroom species with a suitable substrate and growing environment. Read specifications before purchasing spawn.
Pasteurize the Substrate
Pasteurization kills off competitive bacteria and fungi present in the raw substrate materials. This gives the mushroom mycelium a head start to colonize without contamination issues.
Heat pasteurization involves:
- Soaking substrate in water
- Heating to 160-180°F for 1-2 hours
- Allowing to cool before adding spawn
Solar pasteurization uses the sun’s heat to warm substrates left in clear plastic bags or under glass for several hours.
Skipping pasteurization risks inviting molds and other contaminants. While some mushroom varieties are more competition-resistant, pasteurizing the substrate is a reliable prevention method.
Inoculate the Substrate with Spawn
Mushroom spawn contains mycelium – the root-like structure mushrooms grow from. Introducing spawn to your substrate is essential to start the mushroom fruiting process.
When working with spawn:
- Follow handling instructions to avoid contamination
- Use spawn meant for your substrate and species
- Inject or mix spawn thoroughly throughout substrate
- Maintain clean tools and hands
For outdoor logs, dowel spawn is hammered into drilled holes. Bulk substrates like straw get mixed by hand with grain or sawdust spawn.
After inoculation, mushrooms take several weeks or months to fully colonize the substrate before producing mushrooms. Be patient!
Maintain Proper Moisture Levels
Consistent moisture is the most important factor for healthy mushroom growth. Substrate drying out will stall or halt growth.
- Check moisture levels 1-2 times per week
- Gently waterlog or mist beds when needed
- Increase watering frequency during hot, dry weather
- Improve drainage in soggy substrates
Fluctuating between damp and dry spells also stresses growth. Aim to keep the substrate evenly and consistently moist.
Mulching beds helps retain moisture. Position them in naturally damp garden spots. Monitor rainfall and adapt your watering routine accordingly.
Provide Shelter from Heavy Rains
While mushroom beds need steady moisture, getting waterlogged from heavy rains can cause bacteria and molds to take over.
Construct a simple shelter over your mushroom patch:
- Build a slanted roof on posts or lean-to against a shed
- Use plastic sheeting, boards or metal roofing
- Allow space for airflow on all sides
This protects from downpours but still permits the natural light and air mushrooms need to thrive in an outdoor environment.
Monitor for Signs of Contamination
Competitor molds are the most common threat to mushroom crops. Be vigilant in checking for contamination. Signs include:
- Brightly colored mold taking over the substrate
- Foul odors like ammonia
- Mushroom growth stalling with no pins forming
Dispose of badly contaminated substrates safely away from the garden. Identify and correct overly wet, dry or unsanitary growing conditions.
Pick Mushrooms at the Right Time
Knowing the optimal growth stage for harvesting ensures mushrooms reach full maturity. Premature picking reduces yields.
- Oysters – Harvest when caps start to flatten out but before edges curl upward
- Buttons – Pick right before veil breaks and cap expands
- Reishi – Let mature for 6+ months before harvesting
- Lions mane – Snip individual shaggy fruits off stem base as they develop
Use a sharp knife to cut mushrooms rather than pulling and risking damage to developing pins. Handle carefully to avoid bruising.
5 Tips for Maximizing Outdoor Mushroom Yields
Follow this expert advice for bumper harvests from your outdoor mushroom cultivation:
- Start more beds – Increase yields by expanding to additional mushroom logs or beds.
- Test new spots – Try different garden areas to find the microclimate best suited for each variety.
- Promptly re-inoculate – Re-spawn logs/beds right after flush ends to allow continuous harvesting.
- Promote airflow – Prevent humidity pockets where molds thrive by turning logs or gently raking beds.
- Adjust care by season – Adapt your watering and shelter to maintain ideal conditions in all weather.
Growing a selection of mouthwatering mushroom varieties is a fun and doable backyard gardening project. With a shady spot, proper substrate, spawn and a little maintenance, you can enjoy an abundant harvest. Matching the mushroom species’ preferences and providing the right conditions will allow your outdoor mushroom patch to flourish.
Frequently Asked Questions
What is the easiest outdoor mushroom to grow?
Oyster mushrooms are a great beginner variety for outdoor growing. They adapt readily to straw or log substrates and aren’t as prone to contamination as other species.
Can you grow mushrooms outside year round?
In mild climates, mushrooms can fruit year-round. In colder zones, outdoor cultivation is limited to spring through fall. You can move some beds like winecap stropharia into a shed or unheated garage to extend the season.
How long does it take to grow mushrooms outside?
From spawning the substrate to your first harvest takes 2-4 months on average depending on the mushroom variety. Fruiting can continue for 6-18 months before replenishing the mycelium with fresh spawn.
Can you grow mushrooms outside in pots?
Yes, you can cultivate mushrooms in pots, buckets or planter boxes using substrates like soil/compost mixes and supplemented hardwood. This allows you to move them around the garden to optimize sunlight and moisture conditions.