How to Create Agar Plates

The Art of Agar: Precision Cultivation Starts Here

Agar plates are where the deepest skills in mycology begin to unfold. These simple yet powerful tools allow cultivators to observe, isolate, and nurture pure mycelium in a controlled environment — offering a level of precision and insight that liquid culture and grain spawn alone cannot match.

At its core, an agar plate is a small dish filled with a firm, nutrient-rich medium made from agar - a gelatinous substance derived from seaweed - combined with sugars or other additives that feed fungal growth. This creates a perfect microcosm where mycelium can be studied, transferred, and refined.

Build Your Agar Medium

Creating agar starts with a nutrient broth. Below are three reliable recipes, including the popular and ultra-simple PhillyGoldenTeacher 123 method:

PGT's 1-2-3 Instant Potato Agar

Perfect for affordability and quick prep.

1g instant potato flakes

2g light corn syrup or honey

3g agar agar powder

Per 100mL distilled water

🧴 To make 1 liter, simply scale up: 10g potato flakes, 20g sugar, 30g agar.

Instructions:

Mix all ingredients in cool distilled water.

Stir until dissolved.

Heat gently (do not boil), then sterilize for 20–30 minutes at 15 PSI.

Potato Dextrose Agar (PDA) – Traditional & Versatile

200g peeled potatoes

20g dextrose or table sugar

15g agar

1 liter distilled water

Steps:

Boil potatoes, strain, keep the starchy water. Add sugar and agar, top off to 1L, heat and sterilize.

Light Malt Extract Agar (LMEA) – Fast & Reliable

20g light malt extract (LME)

15g agar

1 liter distilled water

Steps:

Mix all, heat gently until dissolved, then sterilize.

Why Media Variety Matters: Enzyme Blindness Explained

Using different agar recipes isn't just about preference - it prevents enzyme blindness. When fungi are grown repeatedly on the same nutrient profile, they may begin to lose the enzymatic diversity needed to digest more complex substrates. This can lead to weak performance on grain, wood, or compost.

By rotating media (like PDA, LMEA, or PGT’s potato flake agar), you encourage diverse enzyme expression, keeping cultures robust and adaptable.

What You Can Do With Agar Work:

• Isolate genetics from spores

• Clone mushrooms from wild or cultivated samples

• Identify contaminants and rescue clean tissue

• Observe growth rates, rhizomorphic structure, or contamination resistance

• Expand your best strains into LC or spawn

Each plate becomes a living story. A small window into fungal intelligence, resilience, and potential. Mastering agar is a mycologist’s rite of passage — and it opens doors to custom strains, stronger cultures, and true cultivation control.