The UK Guide for Small Commercial Mushroom Grow Operations
Across the UK, entrepreneurs are transforming spare rooms, garages, and outbuildings into productive, profitable mushroom-growing operations.
Not factories. Not fields. Just well-designed rooms that produce reliable harvests.
“Commercial” doesn’t have to mean a massive complicated operation. It's about dialling in the right space, a precise environment, and the perfect inputs for consistent, profitable yields.
This guide gives you a clear, practical plan to set up your first small commercial grow. You’ll leave with a room layout, environment targets, an equipment and supply checklist, and all the knowledge you will need to grow and start making money.
Why Start a Small-scale Mushroom Farm?
Demand for fresh, gourmet mushrooms in the UK is climbing. Restaurants, farmers’ markets, shops, and health-conscious consumers want local producers.
Benefits:
- High profit margins with gourmet species
- Low start-up costs compared to most agriculture ventures
- Year-round harvests with indoor growing
- Sustainability using waste streams as feedstocks
Define your target output and species
Pick a weekly target and keep it steady for 8 weeks. That lets you dial rooms before scaling.
- Starter targets: 10 kg, 25 kg, 50 kg, or 100 kg per week
- Rule of thumb: A 3 kg block can yield roughly 0.7–1.0 kg across the first two flushes when dialled in.
- Species mix: Oysters for speed and margin, Lion’s Mane for premium, Chestnut for variety.
- Cycle times: Typically 15–45 days of colonisation and 7–21 days of fruiting, depending on species and temps.
This choice sets bag counts, space, HVAC size, and staffing.
Picking and Building Your Growing Environment
1. Choose a controllable space
You don’t need acres. You need one insulated, washable space with basic services and the ability to control temperature, humidity, airflow, and light.
Good options
- Spare room
- Insulated garage or shed
- Basement or cellar
- Small industrial unit or lock-up
- Shipping container
- Warehouse
2. Pick your layout pattern
There are two proven setups available for small commercial operators. Choose one and commit.
A. Mushroom grow rooms
- One room for incubation and one for fruiting
- Best for cleanliness and stable conditions
- Higher fit-out, very repeatable
B. Mushroom grow tents
- One or more grow tents inside a clean space
- Fast to start, easy to clone as you scale
- Microclimates are simple to dial in
- Can be as small or big as you need to fit your required space
3. Environment targets and control
Dial these in for predictable yields.
Colonisation
- Temperature: 20–24°C
- Humidity: 40–60% humidity
- Air: gentle, ~1–2 air changes per hour
- Light: low is fine
Fruiting
- Temperature: 12–22°C by species
- Humidity: 85–95% humidity with fine control
- Fresh air exchange: enough to manage CO₂
- Airflow: gentle and even to avoid drying out the blocks
- Lighting: 5000–6500K LED on a 12-hour on / 12-hour off cycle.
Mushroom Growing Equipment: The Essential List
1. Sanitation & PPE
- 70% isopropyl alcohol
- Alcohol sprayers
- Gloves & masks
2. Growing environment
3. Climate & air control
-
Humidifier setup
- Get an ultrasonic humidifier – 5 litres for a 3x3m tent, 13 litres for a 3x6m
- An Inkbird IHC-200 humidity controller will automate things for you
- Here's a trick: set the humidifier outside your tent and run a hose in. Saves you from dealing with splash damage on the mushrooms
- Stick with distilled or filtered water to avoid scaling issues
- Every few weeks, give the tank a clean with white vinegar or citric acid
-
Ventilation
- You'll want an exhaust fan with ducting (4 or 6 inch inline works) hooked up to a timer
- Run the exhaust duct high – it'll pull out the warm, humid air and keep condensation under control
-
Air filtration
- Add intake filters to block contaminants
- A basic pre-filter does the job, but HEPA filters are better if you want extra protection
-
Keeping things warm
- The easy option? An electric space heater (though it'll cost you more to run)
- For a more cost-effective DIY approach, apply heating cables to your racking
- Don't forget insulation around your growing area
- Use a thermostat to control your heaters. We recommend an Inkbird ITC-308 to automate temperature management
4. Lighting & monitoring
- 6500K LED fixtures
- Use a simple plug-in timer to maintain a 12/12 light schedule.
5. Shelving & racking
-
Heavy-duty plastic shelving
- We recommend plastic shelving because it's cheap and never rusts - 12x units of this size fit in a 3x3 grow tent
- Avoid most stainless steel racks on the market – they don't use high-quality steel, so they rust surprisingly fast
- Some growers use epoxy-coated racking, but it's pretty expensive and still has metal components that'll eventually rust
- Sizing rule: choose racking that fits your bag/block size with some breathing room
- Keep 10–20 cm between stacks for proper airflow
- Bonus tip: Label each rack bay and shelf position to make rotations way easier
Nice to Have (Not Essential, But Useful)
Grow room upgrades
- Insulation boards on walls and ceilings to stabilise temperatures
- Drainage: trays or a sloped floor to a drain
- Stainless steel work table
- CO₂ meter
DIY lab add-ons (only if you plan to make your own substrate and spawn)
- Flow hood
- Pressure cooker
- Impulse or band sealer
- Additional lab room
Buying Your Core Mushroom Growing Supplies: Spawn and Substrate
Once your room is built, the core components of the farm are the substrate and spawn/genetics. In any commercial setup, consistency is king. Reliable, high-quality substrate and spawn are the fastest route to predictable, profitable harvests.
You have two paths:
1. DIY input paths
If you are working with your own genetics, cultures, or spawn and doing your own inoculations or transfers, line up the following:
Use this path if you want maximum control over strains and scheduling. You will need a colonisation and fruiting room if you go down this path.
2. Done-for-you path
If you want the easiest route, use fruiting kits. Put them straight into fruiting, and harvest. You do not need a colonisation room for this path, only a fruiting environment.
Fruiting blocks and kits
- You can buy mushroom fruiting blocks here
- Block size: 3 kg
- Dimensions: approx. 30 cm L × 15 cm W × 15 cm H
- Yield: you're looking at about 33% of the block weight in mushrooms. So around 1 kg fresh per block, though this varies depending on your conditions
Wholesale Mushroom Supply: Trade Pricing & Partnerships
Setting up the room is the easy part. Staying profitable means consistent yields, reliable genetics, and a supply chain that does not miss when orders come in.
The growers who make real money do not try to manufacture everything. They focus on growing, harvesting, and selling. They let specialists produce substrates and spawn at scale with tight quality control.
Why full DIY backfires
- Hidden costs in equipment, supplies, energy, and wasted batches
- Time sink that turns you into a manufacturer, not a business owner
- Inconsistent quality and higher contamination risk
- Scaling bottlenecks and constant firefighting
Simple scales, complex fails
If you want a simple, scalable supply line for substrate, sterile grain and grow bags, spawn, and genetics, get wholesale trade pricing and a dependable partner. That is how you protect margins and keep output predictable.
Small wholesale orders (under 25 units)
Place a standard wholesale website order at Martian. You can find the multi-pack discounts on the product pages.
25+ units, custom requests, or any questions
Check out the Growth Partner Program for trade pricing and scalable supply.
FAQs
Do I need a flow hood to start?
A well-built still air box can work for small runs. A flow hood adds speed and consistency once you scale.
Can I run incubation and fruiting in the same room?
You can, but expect more contamination and environmental drift. Separate zones perform better.
Can I run this system in a house?
Yes, if you contain humidity and airflow inside tents or a washable room. Protect walls and floors. A small unit is easier for drainage and cleaning.
How much space do I need for 50 kg per week?
One fruiting room with racking for 120–160 active blocks plus an incubation room with 200–250 blocks in rotation.
Got more questions or need some help?
Reach out to us anytime here.
Your Commercial Mushroom Farm Launch Checklist
✅ Lock in your weekly targets and decide which species you'll grow.
✅ Map out your room or tent layout using the lists above.
✅ Buy and install your essential equipment.
✅ Join the Growth Partner Program to unlock wholesale pricing and support.
✅ Plan your weekly supplies: fruiting blocks, substrates, spawn, and genetics.
✅ Start growing mushrooms and start earning from your harvests!