How to Make a Spore Print

I found this rather large Pluteus cervinus (deer mushroom) growing from a stump we’ve been burning. Making a spore print is a great way to help with fungal identification—and it’s simple to do. It’s one of the most important features of identification as well.

All you really need is some aluminum foil and something to place over the mushroom. I used my mushroom knife’s brush to clean it up a bit, but paper towels work just fine. You can also gently blow debris away. This helps keep dirt from falling onto the print and makes the final result much cleaner.

For the cover, I used an old spaghetti bowl, though a slightly larger bowl would have worked better.

Once you’ve cut the stem and cleaned the cap a bit, place it gills-down on the foil. If you’re working with a polypore, the tubes will face down instead. From there, let gravity and nature do the work.

Next, place your container over the mushroom and let it sit for about 24 hours. Try not to disturb it by checking too often—monitoring is fine, but patience helps. It’s also important to consider the size of your mushroom compared to the size of your container. In this case, the large cap and smaller bowl caused quite a bit of humidity to build up. You can see that in the moisture that collected on the bowl and in the small puddles on the spore print itself.

Some people suggest adding a drop of water to the cap before covering it. If you do, keep humidity in mind—you may not need it.

After letting the print dry for a few hours… voilà. A spore print.
The color and pattern can tell you a lot about a mushroom’s identity.

The spore print pictured is a pretty good one. If you look closely, you can see where extra moisture accumulated on the print and concentrated some of the spores. When this happens, you can set the print on a windowsill or in a calm spot away from drafts and let it dry out naturally. Hopefully, you won’t need this step—but it’s good to know what to do if moisture shows up.

Once the print is fully dry, you can carefully fold the foil and store it somewhere dry, such as in an envelope. Over time, these can turn into a nice little collection.

If you manage to make a clean, well-defined print, you can also lightly spray it with hairspray to seal it. Framed spore prints can make surprisingly beautiful and meaningful pieces of art.