How to Make Wild Bird Seed (WBS) Grain Spawn

Cheap • Effective • Beginner-Friendly

Wild Bird Seed (WBS) is one of the most popular grain choices for mushroom hobbyists because it’s inexpensive, widely available, and produces strong, healthy mycelium. You can buy it at most grocery stores, hardware stores, or feed stores — no specialty shops required.

This guide walks you through:
✅ Supplies
✅ Soak + simmer
✅ Drying + loading jars
✅ Pressure cooking
✅ Inoculating with liquid culture OR agar wedges
✅ Troubleshooting

🧂 Supplies

• Wild Bird Seed (no corn is ideal — but corn is fine if that’s what you have)

• Mason jars w/ metal or plastic lids

• Modified lids — filter holes or micropore tape

• Pressure cooker

• Fine mesh strainer or colander
  (flat mesh screen works even faster)

• Large pot

• Clean towel or rack for drying

• Still-Air Box (SAB) or flow hood

⚙️ Step-by-Step

✅ 1) Rinse

Wild bird seed is dusty and usually contains sunflower seeds, cracked corn, and other debris.
None of this is harmful — but removing floaters helps keep your final jars cleaner and less oily.

1. Dump your dry WBS into a large pot or bucket

2. Fill with water

3. Stir with your hand

You’ll notice:

• Dust clouds → water turns brown/yellow

• Sunflower seeds + shells float to the surface

Skim off floaters using:

• A large spoon

• A strainer

• Or just your hand

Why remove sunflower seeds?
Sunflower seeds have oil-rich shells that don’t hydrate well and can slow colonization.
Not mandatory, just helpful.

Keep rinsing + skimming until the water runs mostly clear.

While I was rinsing the grain, my cat Squeaks sat nearby giving me this serious, almost suspicious look.
Not sure if he was judging my technique or cheering me on, hard to tell with cats, but he stayed for the whole process so I’m taking it as approval.

✅ 2) Soak (10–18 hrs)

Place rinsed seed in a bucket or pot and soak 12 hours (overnight works best).

Why soak?

• Rehydrates seed

• Germinates bacterial endospores → easier to kill during PC

Temps don’t matter much.

✅ 3) Simmer (variable, 10–30 min)

Drain the soak water → refill pot → bring to a simmer.

This step finishes hydration.

🔥 Important:
Simmer time varies based on brand, blend, age of seed.

You’re looking for:
✅ Kernels that squish between your fingers
❌ NOT mushy or bursting

Pinch-test method:
Squeeze a seed — it should flatten, not explode into paste.

When in doubt → undercook slightly, not over.

✅ 4) Drain + Steam Dry

Dump into a:

• colander, OR

• flat mesh screen (drains faster)

Let steam escape for 10–30 minutes.

Grain should look:

• Dry on the outside

• Hydrated inside

• No puddles

Shake periodically.

A good tip: Drop a handful on a paper towel. If it leaves a wet spot → keep drying.

✅ 5) Load Jars + Lids

Once the grain surface looks dry, fill your jars about ⅔ full.
This leaves enough room to shake later, which helps the mycelium spread faster.

For lids, you can use:

✅ Filtered lids (best)
→ Usually have a small hole covered by a filter patch, SFD, or micropore tape

OR

✅ DIY option — two holes + micropore tape
→ One hole for gas exchange, one optional for injecting LC

Either one works — mushrooms don’t care as long as the jar can breathe a little.

🔹 With Injection Ports

If your lid has a red/brown rubber injection port, LC can be injected directly through it.

🔹 Without Injection Ports

No problem —
you’ll just crack the lid inside a still-air box (SAB) to add your LC or agar wedge.

Note: Injection ports are convenient, not required.

✅ Add Foil Before Pressure Cooking

Once the lids are on, wrap each jar lid with a single layer of aluminum foil.

Why?

• Prevents moisture inside the pressure cooker from dripping into the filter holes

• Keeps micropore tape from getting wet

• Reduces the chance of soggy grains during sterilization

If filters or tape become saturated, they can:

• Allow contaminants to wick into the jar

• Slow colonization

• Cause clumping

Foil = cheap insurance.

Just wrap loosely — no need to make it airtight.

If using filter patches (SFDs), foil still helps protect them, but don’t wrap so tight that it restricts gas exchange.

✅ 6) Pressure Cook

Load your wrapped jars into the pressure cooker.
They can be upright or on their sides — but upright is easiest for beginners.

✅ Add Water — VERY Important

You MUST add enough water to keep the pressure cooker from boiling dry.

A good guideline:

• ~8 cups (2 quarts) of water
  OR

• Enough to sit ~1 inch below the bottom of the jars

If you’re using a metal trivet at the bottom:
Water level should be at or slightly above the base of the trivet, but not touching the grain inside the jars.

Too little water → PC runs dry → dangerous + ruined batch
Too much water → jars can tip or heat unevenly (not a big deal, just messy)

✅ If unsure → err on the side of more water

✅ Sterilization Time & Pressure

Run at:

15 PSI for 90–120 minutes

→ 90 minutes = fine for pints
→ 120 minutes = safer for quarts or dense packs

Why so long?
This kills bacterial endospores that soaked grains wake up.

If you undercook, jars often:

• Stall

• Sour

• Look wet/slimy

So longer = safer.

✅ After PC

Turn off heat and let the cooker:
→ Cool down and depressurize naturally

Do NOT open early
Rapid depressurization can:

• Crack jars

• Suck contaminants inside as pressure changes

Leave everything shut until:
✅ pressure gauge reads zero
✅ it’s comfortable to touch

Sometimes I just leave it overnight.

🍄 Inoculation Methods

You can inoculate using:

✅ Liquid Culture (LC)

(LC syringe OR agar wedges)

You can inoculate grain two main ways:
✅ Liquid Culture (LC)
✅ Agar wedges

Both work — choose whichever you have.

Work inside a still-air box (SAB) for best results.

✅ Option 1 — Liquid Culture (LC)

🔥 Flame-Sterilize Your Needle

Even if the syringe is brand new, it’s good practice to:

1. Light the needle with a lighter until red-hot

2. Let cool for a moment
   (you can drip a tiny drop of LC to cool if needed)

Flaming ensures you’re starting clean even if the syringe tip touched something during packaging or handling.

With Injection Port

1. Wipe injection point w/ alcohol

2. Flame-sterilize needle

3. Inject 1–3 mL LC

4. Slight shake to distribute

This is the easiest method.

Without Injection Port

Still works totally fine.

1. Place jar in SAB

2. Crack the lid slightly

3. Flame-sterilize needle

4. Squirt 1–3 mL LC onto grain

5. Close lid

The key is keeping airflow still → that’s why SAB helps.

Tip: Avoid injecting too much LC — it can make grains wet/clumpy and slow colonization.

✅ Option 2 — Agar Wedges

The cleaner + more reliable method

You’ll need:

• Small clean craft knife OR scalpel

• Fresh blade recommended

🔥 Sterilize the blade

1. Flame the blade until hot

2. Let cool briefly

3. Wipe w/ alcohol (optional)

Using a fresh craft blade is great — they’re sharp and easy to handle.

Cutting the Agar

Cut agar into small wedges

✅ Smaller pieces = more surface area + faster growth
✅ They also shake around more if you mix later

Dropping Agar Into Grain

Inside SAB:

1. Open grain jar

2. Drop wedge in
   — Ideally against the glass where you can see it

3. Close lid

Next:

✅ Give a gentle shake to get the wedge down into the grain, not stuck on top.
You want it near the middle or bottom so mycelium spreads through the jar evenly.

Some people wait to shake until ~20–30% colonization —
Both methods work. You can shake right away OR after it takes hold.

My preference:
→ Shake lightly right after inoculation so there are multiple inoculation points.

✅ How Much to Use?

• One wedge per jar is enough

• Two wedges speeds colonization a bit

🔁 After Inoculation

• Store at room temp

• Indirect light okay

• Light shaking at ~30% colonization helps spread mycelium

Jar should finish in:
2–4 weeks depending on:

• culture strength

• temp

• water content

⚠️ Troubleshooting

💧 Too Wet / Burst Seeds

→ Mushy grains slow colonization + increase bacteria
→ Undercook next batch

❌ Bacterial Sliminess

• Wet clumps

• Yellowish grains

• Sour smell

Usually caused by:

• Overcooking

• Under-PC

• Dirty LC

Start over.

❗ Mold

Green, black, pink, etc.
→ Toss.

If many jars contaminate → check inoculant.

Why WBS?

• Cheap

• Easy to find

• Excellent yield

• No need for fancy prep

I actually started my entire mushroom journey with WBS because it was all I could find locally — and honestly, it worked great.

If you’re new to grains, WBS is a perfect starter.

✅ Simple Recipe Recap

1. Rinse

2. Soak 12 hrs

3. Simmer 10–30 min → pinch test

4. Drain + dry

5. Load jars

6. PC @ 15 PSI for 90–120 min

7. Inoculate (LC or agar)

❓ FAQ

Do I need an injection port?
No — helpful, but not required.

Is corn okay in WBS?
Fine. Some blends have it. Just break up clumps.

Can I skip simmering?
Not recommended; inconsistent hydration.

Final Thoughts

WBS is cheap, effective, and forgiving.
It’s a great first-grain to learn with, and you don’t need fancy lids or expensive bags — jars are plenty.

Plus, there’s something kind of meditative about rinsing and draining seed… even if your cat looks at you like you’re doing it wrong.

Getting grain spawn dialed in sets you up for bulk methods like tubs and bags, which are great for producing consistent gourmet harvests.