How to wake up a slime mold sclerotium in 48 hours: a complete guide
Have you just received your Physarum polycephalum sclerotium? Here is the step-by-step protocol to wake it up within 48 hours: agar preparation, temperature, darkness, and mistakes to avoid.
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Just received your Physarum polycephalum sclerotium? Here is the step-by-step tutorial to wake it up in 48 hours: the right agar dosage, the soaking technique, the ideal temperature, common mistakes to avoid, and a revival protocol just in case.
Upon arrival, your sclerotium is resting on a 90 mm Ø filter paper — this is its dormancy support. You are now going to move it onto an agar plate to wake it up.
Step 1 — Prepare your agar plate (10 minutes)
The sclerotium needs a stable and already moist surface to emerge from dormancy. The agar provided in your kit forms a gel that retains moisture for days — it does all the work, so you won't need to add water later.
1.5 g of agar per 100 mL of water, i.e., 1.5%. This is our standard dosage, aligned with the educational protocols of CNES and CNRS. Boil it, pour it into the Petri dish to a thickness of ~4 mm, and let it set at room temperature.
Step 2 — Soak the sclerotium, then place it (5 minutes)
Using tweezers, dip the sclerotium into a small amount of water — a small 25 mL container is enough — then take it out and shake it well. It should come out rehydrated, not wet. Then, gently place it in the center of the agar.
This is the only moment in the entire protocol where water is involved. And the shaking is not a detail: free water on the agar is exactly what we want to avoid. Afterwards, not another drop — the agar is already plenty moist.
Close the lid. A standard Petri dish is not airtight; air exchange happens naturally through the rim.
Step 3 — Feed it (Day 1)
Place 2 or 3 oat flakes 1 cm away from the sclerotium. The blob will extend its yellow plasmodium to go and get them — and that is exactly what you want to observe.
Step 4 — Observe the awakening (24 to 48 hours)
At 20-25°C, the first signs appear in 24 hours on average: a translucent yellow border spreading from the sclerotium. The full awakening occurs within 48 hours, with clear, distinct yellow filaments spreading across the agar. Congratulations, your blob is alive.
Then: one or two oat flakes every 2 days, and leave the agar alone. No water, no misting, nothing. When the dish is full, you transfer a piece onto a fresh dish — this practice, repeated, keeps a blob alive for months.
"A sclerotium is never really dead. It's just waiting for the right conditions."
Mistakes to avoid
- Too-diluted agar or free water — the sclerotium drowns
- Placing a dripping wet sclerotium — after soaking, shake it: rehydrated, not wet
- Adding water to the agar — useless and counterproductive, it is already moist
- Direct light — darkness during waking, diffuse light afterwards
- Temperature below 20°C — the blob slows down significantly
- Sugar, chocolate, honey — mold guaranteed
- Forgetting food — the blob goes back into dormancy
After waking: feeding, transferring… or putting it back on pause
As long as you feed it and transfer it, your blob will live for months. But if you go on vacation or want a break, you can put it back into dormancy: place it on a new 90 mm Ø filter paper (your kit contains several spares), let it dry slowly in the open air, then store it in a dry, dark place. It will become a sclerotium again, ready to wait until you want to wake it up — even a year later.
What if nothing happens?
Don't panic, and above all: do not add water. On fresh agar, "lack of moisture" is never the cause. Read our troubleshooting guide, which goes through the real causes one by one and the revival protocol.
100% awakening guaranteed: if your sclerotium doesn't wake up within 7 days despite the revival protocol, we will send you another one for free.
