Agar Work: Advanced Cultivation Technique

Introduction to Agar Work

Agar work is an advanced cultivation technique that involves growing mycelium on agar plates (petri dishes with nutrient agar). This method is essential for isolating clean cultures, selecting strong genetics, making transfers, and maintaining cultures. While more advanced than basic cultivation methods, agar work offers significant advantages for serious cultivators.

Agar work allows you to see mycelial growth patterns, identify contamination early, isolate strong genetics, and create clean cultures for inoculation. It's a fundamental skill for anyone looking to advance their cultivation practice and produce consistent, high-quality results.

What is Agar?

Definition

Agar is a gelatinous substance derived from red algae. It's used as a solid growth medium for microorganisms, including mushroom mycelium. When mixed with nutrients and water, agar forms a solid gel that provides a surface for mycelium to grow on.

Why Use Agar?

Agar work offers several advantages:

• Visual Inspection: See mycelial growth patterns and contamination clearly
• Isolation: Select and isolate strong, clean genetics
• Contamination Control: Identify and remove contaminated areas
• Culture Storage: Maintain cultures for long periods
• Transfers: Make clean transfers to new plates or grain
• Genetic Selection: Choose the best genetics for cultivation

Materials and Equipment

Essential Materials

• Petri dishes (plastic or glass, reusable or disposable)
• Agar powder
• Nutrients (malt extract, potato dextrose, etc.)
• Water
• Pressure cooker or autoclave
• Still air box (SAB) or laminar flow hood
• Scalpel or X-Acto knife
• Alcohol lamp or torch
• Isopropyl alcohol
• Parafilm or micropore tape

Optional Equipment

• Laminar flow hood (for advanced work)
• Incubator (for temperature control)
• Microscope (for detailed inspection)
• Gloves and face mask
• Disinfectant spray

Agar Recipes

Malt Extract Agar (MEA)

A common and effective recipe:

• 20g agar powder
• 20g malt extract
• 1L water
• Optional: 1g yeast extract

Potato Dextrose Agar (PDA)

Another popular recipe:

• 20g agar powder
• 20g potato dextrose
• 1L water

Simple Agar Recipe

For beginners:

• 15g agar powder
• 10g light malt extract
• 1L water

Preparing Agar Plates

Step 1: Mixing

1. Measure agar and nutrients
2. Add to water in a flask or jar
3. Stir to dissolve
4. Heat gently if needed to dissolve completely

Step 2: Sterilization

1. Pour agar mixture into containers (flasks, jars, or directly into petri dishes)
2. Cover with foil or lids
3. Pressure cook at 15 PSI for 20-30 minutes
4. Allow to cool to handling temperature (around 50°C/122°F)

Step 3: Pouring Plates

1. Work in a still air box or laminar flow hood
2. Sterilize work area and equipment
3. Pour agar into petri dishes (about 15-20ml per plate)
4. Cover immediately
5. Allow to solidify
6. Store upside down to prevent condensation on lid

Working in a Still Air Box (SAB)

Setting Up

A still air box is essential for agar work:

1. Use a clear plastic storage container
2. Cut two arm holes in the sides
3. Clean thoroughly with alcohol
4. Place on a clean surface
5. Spray inside with disinfectant
6. Wait for air to settle (10-15 minutes)

Technique

• Work slowly and deliberately
• Minimize hand movements
• Keep everything inside the SAB
• Flame sterilize tools between uses
• Work quickly but carefully

Inoculating Agar Plates

From Spores

1. Prepare spore syringe or print
2. Work in SAB or flow hood
3. Flame sterilize inoculation loop or needle
4. Collect spores
5. Streak or spot on agar
6. Seal plate with parafilm
7. Incubate at appropriate temperature

From Tissue Sample

1. Select a clean, healthy mushroom
2. Split open (preferably inner tissue)
3. Cut small piece of tissue
4. Place on agar plate
5. Seal and incubate

From Liquid Culture

1. Use sterile syringe
2. Dispense small amount on agar
3. Spread with sterile tool
4. Seal and incubate

Making Transfers

Selecting Growth

When making transfers, look for:

• Fast-growing, rhizomorphic mycelium
• Clean, white growth
• No signs of contamination
• Strong, healthy appearance

Transfer Technique

1. Flame sterilize scalpel
2. Cut small piece of mycelium from edge of growth
3. Transfer to new agar plate
4. Place in center or make multiple transfers
5. Seal with parafilm
6. Label with date and source
7. Incubate

Identifying Contamination

Common Contaminants

• Bacteria: Slimy, wet-looking growth
• Mold: Fuzzy, colored growth (green, black, etc.)
• Yeast: Creamy, smooth growth
• Other Fungi: Different growth patterns than mycelium

Mycelium vs. Contamination

Healthy mycelium:

• White, fluffy or stringy
• Rhizomorphic (root-like) growth
• Consistent appearance
• Grows outward from inoculation point

Isolation and Selection

Genetic Isolation

Isolation allows you to:

• Select the best genetics
• Create uniform cultures
• Improve growth characteristics
• Select for desired traits

Selection Criteria

Look for mycelium with:

• Fast growth rate
• Rhizomorphic growth pattern
• Strong, healthy appearance
• No contamination
• Consistent characteristics

Storage and Maintenance

Short-Term Storage

• Store plates upside down
• Keep at room temperature or slightly cooler
• Use within weeks to months
• Check regularly for contamination

Long-Term Storage

• Store in refrigerator (slows growth)
• Can last months to years
• Make transfers periodically
• Consider slants for very long storage

Troubleshooting

Common Problems

• Contamination: Improve sterile technique, check agar preparation
• No Growth: Check spores/culture viability, temperature
• Slow Growth: Check nutrients, temperature, agar quality
• Condensation: Store plates upside down, allow to cool properly
• Drying Out: Seal properly, store in appropriate conditions

Advanced Techniques

Slant Tubes

For long-term storage:

• Use test tubes with agar slants
• Inoculate and store in refrigerator
• Can last years
• Make transfers when needed

Water Culture

Alternative storage method:

• Store mycelium in sterile water
• Can last months
• Transfer to agar when needed

Best Practices

• Always work in clean, sterile conditions
• Flame sterilize tools between uses
• Work quickly but carefully
• Label everything clearly
• Keep detailed records
• Make backups of important cultures
• Regularly check for contamination
• Practice good hygiene

Conclusion

Agar work is an essential skill for advanced mushroom cultivation. While it requires more equipment and technique than basic methods, it offers significant advantages in terms of contamination control, genetic selection, and culture maintenance.

With practice and proper technique, agar work becomes an invaluable tool for producing consistent, high-quality results. Start with simple techniques and gradually advance as you gain experience and confidence.

Remember: Sterile technique is crucial for success. Take your time, be patient, and don't be discouraged by contamination - it's part of the learning process.