How to Store Mushroom Cultures Long Term (Spore Prints, Liquid Culture & Grain)

When you start growing mushrooms regularly, it’s smart to keep backup cultures on hand. Life gets busy, grows stall, or you just want to pick up again months later — if you know how to store your cultures correctly, you’ll never have to start from scratch.

This guide covers the most practical long-term storage methods for home growers and small producers: spore prints, spore syringes, liquid culture (LC), agar plates/slants, and grain spawn. We’ll also talk about temperature control and some affordable gear that makes the job easier.

1. Storing Spore Prints

• How: Print on foil or parchment paper, let dry overnight, then fold and slip into a small zip bag or foil packet.

• Environment: Cool, dry, dark. A sealed jar or Tupperware with a silica gel pack works well.

• Longevity: Often several years.

Tip — label everything with species and date before you forget.

2. Spore Syringes

• How: Keep the syringe capped and sealed in a clean zip bag or container.

• Environment: Refrigerator or cool dark cupboard (50–60°F is ideal).

• Longevity: 6–12 months is common, sometimes longer if kept cold and clean.

If you plan to use them within a year, refrigeration is usually enough.

3. Liquid Culture (LC)

• How: LC is live mycelium in nutrient broth. Keep the jar or syringe sealed.

• Environment: Refrigerator (35–45°F).

• Longevity: 3–9 months is typical.

You can stretch this by refreshing the LC — take a small piece and inoculate new broth before the old one gets tired.

4. Agar Plates and Slants

Agar is great for keeping clean, vigorous mycelium.

• Plates: Wrap in parafilm or cling film and refrigerate. Good for ~2–6 months.

• Slants: A test tube filled with agar on a slant gives the mycelium more surface and less chance of drying. These can last 6–12+ months refrigerated.

If you’ve seen “agar tubes” — that’s what people mean: agar poured into test tubes at an angle and sealed.

5. Grain Spawn (Short-Term)

Many growers don’t realize colonized grain can be “paused.”

I’ve stored fully colonized grain jars in the fridge for a couple weeks to a month and they came back strong when spawned later. This is handy if life interrupts your grow or you want to sync timing.

• How: Let the grain fully colonize, then refrigerate.

• Longevity: Usually 4–6 weeks is fine, sometimes longer. Don’t expect indefinite storage; this is a short-term pause.

6. Temperature Tools (Optional but Helpful)

• Mini fridge or wine fridge: Great for a controlled cool zone (45–55°F) if your home fridge is too cold or crowded.

• Insulated cooler in a cool basement: Works if power isn’t an option.

If you’re prepping long-term, a small wine fridge lets you store LC, plates, and spawn at a safe, steady temperature.

Gear I Recommend (Affiliate Links)

• Mason jars — for grain and LC

• Parafilm — for sealing plates

• Test tubes/slants — for long-term agar

• Mini wine fridge — great for culture storage

Affiliate disclosure: I may earn a small commission if you buy through these links, at no extra cost to you.

Want to Go Deeper?

If you’d like to master culture work and grain-to-bulk growing, my Mushroom Substrate & Culture Guide covers LC, agar, spawn, and more in detail — it’s written for home and prepping setups.

Final Thoughts

You don’t need a fancy lab to build a reliable mushroom “seed bank.” By using one or two of these methods — especially spore prints for ultra-long storage and refrigerated grain for short-term — you’ll always have a backup plan when it’s time to grow again.