Clean the Straw

Why straw needs cleaning

Our mushrooms will grow in straw. Straw is dried plant stems, like the yellow stuff on a farm. Oyster mushrooms love to eat it.

But straw fresh from a bag has lots of tiny bugs and molds hiding in it. We call these competitors, because they want to eat the straw too. If we do not clean the straw first, the molds might win and our mushrooms might lose.

So before we start, wash your hands. Then let's make the straw clean.

Hot water does the cleaning

We clean straw with hot water. This is called pasteurising. The heat is like a warm bath that is too hot for the molds and bugs, so they go away. But it is just right for the tough mushroom spawn we add later.

The hot water part is a grown-up job. Hot water can burn, so a grown-up handles the pot and the heat every time. You get the safe and fun jobs: measuring, timing, and watching.

The warm straw bath

Here is how the straw bath works. A grown-up heats a big pot of water until it is hot but not boiling. The straw goes in and stays under the water.

Your jobs are the best ones:

1. Chop the straw into short pieces first, about as long as your hand. Short pieces are easier to pack later.

2. Be the timer. The straw soaks in the hot water for about one hour.

3. Watch the clock and call out when time is up.

Cool and drip dry

After the hour, a grown-up lifts the straw out to cool. Never touch it while it is hot!

Now the straw needs to drip dry. Let the extra water drain away. We want the straw damp, not soggy.

Here is a fun test you can do once it is cool. Grab a handful and squeeze. You want only a few drops of water to drip out. If lots of water pours out, it is too wet. Let it drain longer.

Clean, damp, and cool straw is the perfect home for our mushroom spawn. Warm water for the bath, but always let a grown-up handle the heat.

Now our straw is ready. Next, we layer it up and fill the tower!