The pest every monotub grower eventually fights
You've done everything right. Pasteurized your substrate. Sterilized your grain. Maintained sterile technique through inoculation. Set up your monotub in a clean environment. Spawn run is going beautifully — the substrate is colonizing white and the room temperature is perfect.
Then on day 18, you lift the lid for a quick check and dozens of tiny black gnats fly out.
This is the most common pest problem in monotub cultivation. Fungus gnats (Bradysia species) and shore flies (Scatella species) are attracted to the warm, moist, decaying organic matter that substrate provides. They sneak in through:
- The lid's air-exchange holes during FAE cycles
- Open lids during inspection and harvest
- Substrate ingredients that weren't fully pasteurized
- Adjacent plants or organic matter in the same room
- Outdoor flying insects that find their way indoors
Once gnats establish a population in your monotub, the problem compounds:
- Adult gnats lay eggs in the substrate
- Eggs hatch into larvae that feed on mycelium and developing pins
- Larvae mature into adults that lay more eggs
- A single grow can produce thousands of gnats if uncontrolled
- The infestation spreads to other tubs and grows
Colorado Cultures Gnat B Gone is the solution. A 1-ounce container of all-organic, all-natural powder formulated specifically for monotub gnat control. Lightly dust your substrate and watch the infestation disappear.
How it works
Gnat B Gone targets gnats at every stage of their life cycle:
- Eggs: The powder coats the substrate surface, drying out and killing eggs before they can hatch
- Larvae: Larvae that contact the powder are killed via mechanical and dehydrating action
- Adults: Adult gnats that walk through the powder pick it up on their bodies and legs, leading to their death within hours
The mechanism is purely physical and dehydrating, not chemical. The powder:
- Absorbs moisture from the gnat's exoskeleton, leading to dehydration
- Has microscopic abrasive properties that damage the gnat's protective cuticle
- Doesn't affect mycelium — the powder is benign to fungal growth
- Doesn't affect mushroom fruit bodies — the powder is food-safe in cultivation contexts
The dehydrating mechanism is the same principle used by diatomaceous earth — a well-known organic insecticide that's been used in horticulture for over 100 years.
[VERIFY: confirm whether Gnat B Gone is diatomaceous earth-based, kaolin-clay-based, or another specific organic powder formulation]
All-organic, all-natural
The Gnat B Gone formula is:
- 100% organic ingredients — no synthetic insecticides
- All-natural — no chemical additives
- Safe around food preparation areas — non-toxic if accidentally ingested in trace amounts
- Safe for pets — won't harm dogs, cats, or other household pets
- Safe around children — non-toxic, no special safety precautions beyond standard household chemicals
- OMRI-listed compatible [VERIFY exact certifications]
- Doesn't enter the food chain — applied to the substrate, not the mushroom fruit bodies
For cultivators who want pest control without introducing chemicals into the cultivation environment, this is the right product. Especially for those:
- Growing mushrooms for consumption (food safety priority)
- Cultivating medicinal mushrooms for daily supplementation
- Hosting children or pets near the cultivation space
- Following organic-aligned cultivation principles
- Worried about residue effects on the mushroom harvest
When you'd use it
The product is intended for active gnat infestations in monotub or fruiting chamber environments. Specifically:
Active infestation
- You can see adult gnats flying when you open the lid
- You see larvae in the substrate (small white worms)
- Yellow sticky traps near the chamber show 3+ gnats per day
- Other monotubs in the same room are also affected
Apply immediately upon noticing gnats. The earlier you intervene, the less population growth to combat.
Preventive application
For cultivators who've had gnat problems in previous grows:
- Apply at chamber setup before introducing spawn
- Pre-treat the substrate surface during initial pasteurization or after spawning
- Lightly dust the chamber interior during FAE cycles
Prevention is more effective than treatment. If you've had gnats once, expect them next time unless you implement preventive measures.
Multi-tub operations
Martha tent and multi-tub setups are particularly susceptible because:
- Larger total substrate volume = more habitat for gnats
- Shared air space = one tub's infestation spreads to all tubs
- More frequent lid openings during management = more entry opportunities
- Multi-block fruiting = larvae compete with mycelium for substrate
For multi-tub operations, regular preventive application is the right approach.
What 1 oz of Gnat B Gone covers
A 1-ounce container provides enough powder for:
- 8-20 monotub applications (depending on light vs. heavy dusting)
- 6-12 months of regular use for a typical home cultivator
- 2-4 months of regular use for serious cultivators running 3-6 monotubs
The light-dusting application rate means a little goes a long way. Don't over-apply — you're not trying to bury the substrate; you're creating a thin protective layer that targets gnats while allowing mycelium to continue colonizing.
Application
The basic workflow:
- Open the chamber (lid or fruiting hole)
- Use a sieve, salt shaker, or other fine-pored applicator to distribute the powder
- Lightly dust the substrate surface — aim for a thin, even coverage of approximately 1/16" depth
- Pay special attention to:
- Substrate edges (gnats often lay eggs along the perimeter)
- Visible gnat larvae areas
- The interior chamber walls
- Around the air-exchange holes
- Close the chamber and return to normal operating conditions
The full application protocol is in the How to Use tab.
Who buys this
- Cultivators with current gnat problems — the immediate-action use case
- Cultivators who've had gnats in previous grows — preventive application makes sense
- Multi-tub and Martha tent operators — gnats spread quickly across multi-grow setups
- Cultivators with houseplants that might be a gnat source
- Cultivators in seasons or climates where gnats are seasonally active
- Cultivators near outdoor spaces where flying insects can migrate indoors
- Beginner cultivators wanting to add insurance against pest problems
- Cultivators committed to organic methods who avoid chemical insecticides
- Cultivators sensitive to chemical exposure (allergies, kids, pets) who need non-toxic pest control
What this is NOT
- Not a pesticide for non-mushroom applications. Designed specifically for mushroom cultivation. May not be effective on other pest types.
- Not for chemical insecticide use. This is a physical/dehydrating action product. If you need broad-spectrum pesticide, look elsewhere.
- Not for outdoor use. Indoor monotub/chamber application only.
- Not for direct fruit-body application. Apply to substrate surface, not to mushrooms themselves.
- Not effective against bacteria or mold. Gnats only. For bacterial or mold issues, see other Colorado Cultures products (Fungi Fuel for substrate microbiome support; standard contamination protocols).
- Not edible. Don't intentionally consume; designed for substrate application only.
- Not a substitute for sterile technique. Sterile setup prevents many gnat problems before they start.
Pairing with other Colorado Cultures products
Gnat B Gone is part of a complete cultivation toolkit:
- Fungi Fuel — substrate microbiome support; complementary, not competitive (Fungi Fuel supports beneficial microbes; Gnat B Gone targets pests)
- Ultrasonic Humidifier + Hygrometer — chamber environment control
- Waterproof Myco Fans 2-pack — air circulation that reduces gnat habitat
- Premium Disposable Face Masks + Nitrile Gloves — PPE for application
- Full Flush Bin / H2Shroom Fruiting Chamber — chambers compatible with Gnat B Gone use
- Sticky traps (sold separately from any garden supply) — complementary tool for catching adult gnats
- Sorghum AIO grain bags + masters mix — pre-sterilized inputs that reduce contamination risk that creates gnat habitat
The complete pest-prevention stack:
- Sterilize grain and substrate properly — eliminates breeding habitat
- Maintain chamber humidity and FAE — minimizes pest-attracting conditions
- Apply Gnat B Gone preventively — provides ongoing pest barrier
- Use sticky traps to catch any gnats that do appear
- Inspect daily for early intervention
Effectiveness expectations
In typical use, you should see:
- First 24-48 hours: Reduction in visible adult gnat activity
- Days 3-7: Larvae die off (no new adult emergence)
- Days 7-14: Egg-stage gnats stop hatching
- Days 14-21: Population effectively eliminated
A complete cycle from infestation to elimination typically takes 2-3 weeks with Gnat B Gone application. The persistent action of the powder provides ongoing protection without needing daily re-application.
A note on the 1oz format
1 ounce sounds small, but the application rate is light dusting, not heavy application. The format is sized for:
- Multi-month coverage for typical home cultivation
- Travel-friendly — fits in any toolkit or supply bag
- Easy to store — small footprint, doesn't dominate your cultivation supplies
- Cost-effective at this format — purchasing larger formats unnecessary for most users
Commercial cultivators or those facing severe ongoing gnat pressure may want to purchase multiple 1oz containers or inquire about bulk pricing.