Grow Guide

🍄 Mushroom Cultivation in Ready-to-Grow (RTG) Bags

A Comprehensive Guide to Mushroom Biology, Cultivation, Processing, and Utilization

Introduction to Mycology

History of Mycology and Mushroom Cultivation

Mycology, the scientific study of fungi, traces back thousands of years with mushrooms valued for food, medicine, and spirituality. Ancient cultures across Asia, Europe, and the Americas recognized and cultivated mushrooms. Modern mycology began in earnest in the 18th century with systematic documentation and experimentation, paving the way for today's advanced cultivation methods.

Understanding Mushroom Biology

Mushroom Anatomy

• Cap (Pileus): Protects spore-producing surfaces.
• Gills/Pores: Structures beneath the cap releasing spores.
• Stem (Stipe): Supports the cap.
• Mycelium: Network of fungal threads that colonize substrate.
• Spores: Reproductive units dispersed to form new mycelium.

Lifecycle

Mushrooms begin as spores, germinate into mycelium, colonize substrates, form primordia (pinheads), and finally mature into fruiting bodies. Harvesting mushrooms at peak maturity ensures optimal nutrition and quality.

Nutritional and Environmental Needs

• Carbon Source: Wood, straw, manure.
• Nitrogen Source: Supplemented through substrates like grains.
• Humidity: 70–90% during fruiting.
• Temperature: Species-specific (generally 60–80°F).
• Light: Indirect natural or artificial light to initiate fruiting.
• Oxygen & CO₂: Low CO₂ and fresh air exchange essential during fruiting.

Important Mycological Terms and Processes

• Spawn: Substrate colonized by mycelium.
• Colonization: Growth of mycelium throughout a substrate.
• Pinning: Formation of mushroom primordia.
• Fruiting: Development of mature mushrooms.
• Cold Shocking: Exposure to cold to trigger fruiting (species-specific).
• Pasteurization/Sterilization: Methods to eliminate contaminants in substrates.
• Mycorrhizal: Symbiotic fungi-plant root relationship (not used in RTG bags).

Growing Mushrooms with RTG Bags

1. Choosing a Strain

Choosing the Right Mushroom Strain

Selecting the best mushroom strain is a critical first step in successful cultivation. Consider both your personal goals and the environmental conditions you can realistically maintain. Here’s how to make the ideal choice:

Define Your Goals

• Culinary Use: Opt for strains with excellent taste and texture, such as Oyster, Shiitake, or Maitake.
• Medicinal Properties: Consider Lion’s Mane (cognitive health), Reishi (immune support), Turkey Tail (immune-boosting), or Cordyceps (energy and stamina).
• Commercial Yield: High-yielding, fast-growing strains like Oyster mushrooms are ideal.
• Personal Enjoyment or Experimentation: Unique strains such as Enoki or Chicken of the Woods offer novelty and interesting challenges.

Evaluating Environmental Conditions

Temperature:

• Warm Conditions (70–80°F / 21–27°C): Oysters (Golden, Pink), Reishi, and Shiitake.
• Cooler Conditions (55–70°F / 13–21°C): King Oyster, Lion’s Mane, Enoki, Maitake, and Pioppino.

Humidity:

• High Humidity (85–95%): Essential for mushrooms like Oyster, Shiitake, Lion’s Mane, and Enoki.
• Moderate Humidity (70–85%): Reishi and Turkey Tail are more adaptable to slightly lower humidity.

Airflow & Fresh Air Exchange (FAE):

• High Fresh Air Exchange: Oysters and Shiitake require abundant fresh air to avoid elongated stems and poor cap formation.
• Moderate Fresh Air Exchange: Lion’s Mane and Reishi can tolerate lower FAE levels without adverse effects.

Light:

• Indirect, Diffused Light: Beneficial for most edible and medicinal mushrooms, aiding proper growth and coloration.
• Minimal Light: Certain strains like Enoki develop their characteristic long, pale appearance with minimal exposure to light.

Practical Considerations

• Ease of Cultivation: Beginners often find Oyster mushrooms easiest due to rapid colonization and forgiving nature.
• Time to Harvest: Faster strains (Oysters: ~3–4 weeks) versus slower strains (Shiitake: ~8–14 weeks).
• Space and Equipment: Space-efficient strains like Pioppino and Enoki versus sprawling mushrooms such as Chicken of the Woods.

Final Thoughts

Choosing your strain thoughtfully ensures not only a successful harvest but also maximizes enjoyment and productivity in your mushroom-growing journey. Align your goals and growing capabilities realistically to pick the perfect match. Using the chart provided at the end, you can pinpoint what strain may be the best for you.

2. Receiving & Unpacking Your Grow Bags

First impressions matter. As soon as your RTG bags arrive, inspect thoroughly and contact support if any damage or contamination is suspected.

• Prepare your space:
• Clean, sanitized, minimal air movement
• Free from pets, dust, pests, open windows, or vents
• Sanitize tools and work surfaces with 70% isopropyl alcohol or a 1:10 bleach solution
• Handling protocols:
• Use sanitized or fresh nitrile gloves
• Avoid touching the filter patch
• Open boxes carefully (no sharp tools near bags)
• Visual Inspection Checklist:
  ✅ Healthy mycelium: Bright white, fluffy or ropey
  ✅ Bag intact: No punctures, tears, or damaged seals
  ✅ Filter patch: Firmly sealed, unblocked
  ✅ Fresh smell: Earthy, mushroom-like
  🚫 Off smells: Sour, rotten, ammonia-like odors
  🚫 Discoloration: Green, blue, black, pink, or yellow patches = contamination
  🚫 Standing water or slimy substrate = excess moisture/bacteria

3. Storing RTG Bags Before Fruiting

Until you're ready to cut and fruit the bags:

• Ideal storage conditions:
• Temperature: 60–70°F (15–21°C)
• Dry and dark or dimly lit area
• Minimal temp swings
• DO NOT refrigerate unless necessary for cold shock or delaying growth
• Stacking advice:
• No more than 2–3 bags high
• Avoid compacting substrate or blocking filters
• Use sanitized shelving or totes for organization
• Cleanliness reminders:
• Wash/sanitize hands or gloves between every bag
• Sanitize tools and surfaces regularly

4. Colonization / Incubation Phase

RTG bags often arrive partially or fully colonized. However, some species or bags may need more time. After colonization/incubation is complete, some strains may benefit from cold shocking before attempting to fruit them.

• Ideal conditions for colonization:
• Temperature: 65–78°F (18–25°C) depending on species
• Lighting: Indirect or complete darkness
• Airflow: Minimal (avoid drying)
• Humidity: Not important at this stage, bags are sealed
• General colonization timelines:
• Pleurotus: 2-4 weeks
• Hericium: 3-4 weeks
• Reishi: 6-8 weeks
• Shiitake: 12-14 weeks
• How to know colonization is complete:
  ✅ Substrate is white and dense with mycelium
  ✅ Growth is uniform and no signs of contamination
  ✅ Pinheads may appear (indicates readiness)
  ✅ Shiitake bags begin browning as they mature

Cold Shocking Techniques

Cold shocking helps initiate fruiting in certain mushrooms, such as Shiitake, by:

• Refrigerating fully colonized bags at 40°F (4°C) for 24–72 hours.
• Soaking bags in cold, clean water overnight before placing them in the fruiting environment.

Cold can also be used strategically to delay fruiting or slow further colonization temporarily if production timelines must be adjusted.

5. Cutting & Fruiting – The Most Critical Moment

Opening the bag is the highest-risk time for contamination. Be strategic:

• Where to cut:
• Top fruiting or side fruiting
• When to cut:
• Only after full colonization and in a clean space
• Handling reminder:
• This is the moment the sterile environment becomes vulnerable. Take your time and be clean!

6. Fruiting Bag Cut Types & Techniques

There are many different methods for managing the growth of your mushrooms in bags but usually the difference is top fruiting vs side fruiting. Although some mushrooms will fruit best being removed from the bag completely and sometimes your setup will determine how to cut your bag. Fruiting mushrooms from bags is an art, everyone does it differently so find what works for you.

For top fruiting, the mushrooms grow from the top of the substrate. Sometimes this is done without opening the bag, or by notching a corner off the top to introduce restricted airflow. Other times this entails removing the top completely, either leaving the extra plastic as a collar or rolling it down for adjustment if needed. If careful, the top of the bag can be slit on the sides to allow it to be folded open and closed for repeated harvests.

Side fruiting is usually done from slits or holes cut into the sides of the bag. The top of the bag would be punctured to release air before securing it down tightly with tape or bands. Then small cuts can be made in the sides of the bag, with different shapes and sizes of cuts producing different results. Side fruiting can also be done by allowing the top of the block to start pinning, removing the top of the bag, and placing the bag on its side.

Species	Fruiting Method	Notes
Oysters (Most varieties)	Side	Can also top fruit if humidity is high
King & Black Pearl Oysters	Top	For long stems keep CO₂ high by leaving bag closed
Hericium	Side	Pins form as white puffballs, harvest before browning
Shiitake	Unbagged	Fruits all over the block so unbagged on a tray is best
Reishi	Top	Antlers = stagnant air; Conks = fresh air/light.
Enoki	Top	Bag might not be opened until first harvest

 

7. Fruiting Environment Options

Your setup matters. Not all growing setups match all grower’s goals. We have 2 large growing tents with air conditioning, exhaust, humidifiers, automation timers and computers, and other specialized equipment. I started growing mushrooms with mason jars, a steamer pot, clear plastic totes and a spray bottle. My dad put a Blue Oyster bag in his laundry room window and got better harvests than I ever have. Do what feels right, try to recycle items, experiment and have fun! These are some suggestions for general growing setups:

Minimal

• Some mushrooms simply will not be successful if grown without a specific growing environment.
• Many strains can produce great harvests in normal room temperatures, with the most common issue being controlling the humidity.
• Adjusting the fruiting method to increase humidity at risk of reduced production or quality is possible. For example, top fruiting Lion’s Mane in the bag rather than side fruiting from slits.
• Humidity can be sufficient through hand misting as needed throughout the day but even a cardboard box can be used to improve the environmental control for your grow bag.

Tubs & Totes (Ideal for small grows)

• Filtered air holes, small fans, or leaving the lid slightly ajar help airflow.
• Wet perlite, a mini humidifier, or simply misting a few times daily improve humidity.

Grow Tents (Scalable and Controlled)

• Large, modular, relatively cheap. These give the use control over many features with automated equipment to manage the temperature, humidity and airflow.
• Even a small grower may benefit from investing in a grow tent when compared to the cost of DIY setups or the cost of reduced production from your grow bags.

8. Contamination: Prevention, Identification & Response

Even with the best practices, contamination can occur. Be alert and act fast.

Common Contaminants:

Contaminant	Appearance	Smell
Trichoderma (green mold)	Bright green spots	Musty or earthy
Aspergillus (black mold)	Black fuzzy patches	Chemical or acrid
Bacteria	Pink, orange slime	Sour, rotten, ammonia-like
Cobweb mold	Gray, thin fuzz	Slightly musty
Yellow/Orange liquid	Mycelial metabolite (normal if small)	Sharp or foul if excessive

What To Do:

Contact the supplier with photos, if possible, for support in troubleshooting or replacement.

• Remove the bag:
  Best option for serious contamination—seal in another bag and discard away from grow area.
• Excise the section (advanced):
  For small surface mold, cut out the section using a flame-sterilized blade. Only attempt if you’re experienced and comfortable with this not being successful.
• Spot treatment (limited cases):
• Cobweb mold: 3% hydrogen peroxide spray
• Bacteria: 70% isopropyl alcohol or antimicrobial mist (may damage mycelium)

Health & Safety Warning:

Contaminants can pose serious respiratory risks. If you're unsure, do not fruit the bag. Take clear photos and contact your supplier. Never compost questionable blocks near edible crops or ventilation.

9. Harvesting, Storing, and Processing Mushrooms

Harvesting Techniques

 

• Twist and pull gently or cut cleanly at the base.
• Handle mushrooms carefully to avoid bruising.

Storage Methods

 

• Fresh: Refrigerate in breathable containers; consume within 1–2 weeks.
• Drying: Air or dehydrator drying until crisp.
• Freezing: Slice and freeze for cooking later.
• Canning: Preserve mushrooms by canning or pickling for long-term storage.

Processing for Multiple Harvests

 

• Maintain humidity and fresh air exchange post-harvest.
• Carefully remove residual mushroom bases to encourage subsequent flushes.
• Expect reduced yields with each subsequent flush (typically 2–4 flushes per bag).

 

10. Nutritional and Medicinal Compounds in Mushrooms

 

• Hericium: Nerve growth factor stimulants; cognitive support.
• Oyster: High protein, vitamins B and D; cholesterol-lowering beta-glucans.
• Reishi: Immune-modulating polysaccharides, anti-inflammatory compounds.
• Shiitake: Vitamin D, antiviral and immune-enhancing lentinan.
• Enoki: Antioxidants, anti-cancer polysaccharides.

 

11. Utilizing Spent Grow Bags

 

Determining Completion

A grow bag is considered "spent" when yields significantly diminish or contamination occurs.

 

Sustainable Use of Spent Bags

 

• Composting: Rich organic fertilizer for gardens.
• Inoculating Waste Products: Cardboard, coffee grounds, or wood chips for additional mushroom production.
• Reducing Substrate Needs: Blend spent substrates with fresh material for new grow bags.

 

Conclusion

This comprehensive guide provides essential knowledge and practical insights for successfully growing, harvesting, and utilizing mushrooms from RTG bags, supporting both personal and commercial cultivation goals. Please contact support with any questions or concerns regarding your mushroom grow bags. Don’t forget to have fun!

 

Strain Selection Chart

 

Mushroom	Temp. (°F)	Spawn Colonization	Substrate Incubation	Fruiting	Total Growth	Fruiting Method
Blue Oyster	60–85°F	2–4 weeks	2–3 weeks	1–2 weeks	5–9 weeks	Side
Golden Oyster	65–85°F	2–4 weeks	2–3 weeks	1–2 weeks	5–9 weeks	Side
Italian Oyster	55–75°F	2–4 weeks	2–4 weeks	1–2 weeks	5–10 weeks	Side
Pink Oyster	70–90°F	2–4 weeks	2–3 weeks	1–2 weeks	5–9 weeks	Side
Salmon Oyster	65–85°F	2–4 weeks	2–3 weeks	1–2 weeks	5–9 weeks	Side
Pohu Oyster	55–75°F	2–4 weeks	2–4 weeks	1–2 weeks	5–10 weeks	Side
King Oyster	55–75°F	2–4 weeks	3–4 weeks	1–2 weeks	6–10 weeks	Top
King Tuber Oyster	55–75°F	2–4 weeks	3–4 weeks	1–2 weeks	6–10 weeks	Undetermined
Black Pearl King Oyster	60–80°F	2–4 weeks	3–4 weeks	1–2 weeks	6–10 weeks	Side
Velvet Pioppino	50–70°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Top
Late Oyster	50–70°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Undetermined
Black Poplar	50–70°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Top
Bear’s Head	60–80°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Side
Coral Tooth	60–80°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Side
Conifer Coral	55–75°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Side
Lion’s Mane	60–80°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Side
Tiered Tooth Fungus	60–80°F	2–4 weeks	3–4 weeks	2–3 weeks	7–11 weeks	Side
Shiitake	55–75°F	2–4 weeks	12–14 weeks	1–2 weeks	15–20 weeks	Unbagged
Freckled Chestnut	55–75°F	2–4 weeks	3–5 weeks	1–2 weeks	6–11 weeks	Top
Nameko	50–65°F	2–4 weeks	3–5 weeks	1–2 weeks	6–11 weeks	Top
Beech	50–65°F	2–4 weeks	3–5 weeks	1–2 weeks	6–11 weeks	Top
Antler Reishi	70–85°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Top
Basilisk Fungus	60–80°F	2–4 weeks	2–3 weeks	2–3 weeks	6–10 weeks	Top
Bamboo Reishi	70–85°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Top
Black Reishi	70–85°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Top
Red Reishi	70–85°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Top
Yellow Reishi	70–85°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Top
Turkey Tail	50–70°F	2–4 weeks	6–8 weeks	8–10 weeks	16–22 weeks	Side
Enoki (Golden)	45–65°F	2–4 weeks	6–8 weeks	6–8 weeks	14–20 weeks	Top
Enoki (White)	45–65°F	2–4 weeks	6–8 weeks	6–8 weeks	14–20 weeks	Top
Hen of the Wood	50–65°F	2–4 weeks	8–10 weeks	6–8 weeks	16–22 weeks	Undetermined
Portobello	65–75°F	2–4 weeks	3–4 weeks	3–5 weeks	8–13 weeks	Trays
Cordyceps	60–75°F	2–4 weeks	8–10 weeks	8–10 weeks	18–24 weeks	Jars
Chicken of the Woods	50–70°F	2–4 weeks	8–10 weeks	8–10 weeks	18–24 weeks	Logs
Chicken of the Woods (White-Pored)	50–70°F	2–4 weeks	8–10 weeks	8–10 weeks	18–24 weeks	Logs