DIY Plant Pressing

Dried plant specimen attached to paper, and a handwritten specimen label identifying the plant

Field Museum specimen of Hill’s thistle (Cirsium hillii) found in Elgin, Illinois, in 1918.

How does a plant specimen get turned into an herbarium sheet, ready for a Museum collection? In order for plants to be carefully cataloged and preserved so that they can be studied well into the future, they first have to be dried and pressed. You can do something similar at home—this DIY project is sort of like making a layer cake (or lasagna, depending on your tastes):

Step 1: Find your plants

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Two plant pickings on newspaper

Gather a couple plant specimens (be sure they’re in your own yard or an area where you’re allowed to collect!). Botany collections assistant Anna Balla gathered some local plants: climbing nightshade (Solanum dulcamara), gingko (Ginkgo biloba), chocolate mint or peppermint (Mentha piperita), and black medick (Medicago lupulina) from the legume family. The more complete the specimen, the better—include from the top of the flower or leaves to the root, if possible.

Step 2: Fold them into newspaper

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Ginkgo leaves resting on newspaper

Either keep the specimens moist until you’re ready to press them, or press shortly after picking them. Fold the specimen inside a few sheets of newspaper to absorb the moisture, using additional paper for larger specimens. If you have blotting paper, fold that outside of the newspaper.

Step 3: Start layering

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A grid made of wood, and stacked layers of the grid, cardboard, and paper

 

At the Museum, we use a wooden, gridded plant press, which allows air to circulate and dry the specimens evenly. If you don’t have a plant press, you can use extra pieces of cardboard or plain pieces of wood. Starting with the layer of wood on the bottom, begin alternating cardboard, blotting paper, and then the specimen in newspaper followed by more blotting paper. You can add multiple plant specimens to the same “cake,” as long as you keep alternating layers!   

Step 4: Wait for them to dry

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A hand placing a heavy wooden weight with a handle on a wooden stack.

After placing the other wooden end of the plant press on the last piece of cardboard, secure it with an adjustable strap and a heavy weight on top—you can use large books or other things you have at home. It will take at least a week for the specimen to dry, and longer if it’s a larger plant. You can check the specimen periodically to see how it’s looking and swap out paper if it becomes damp. Once your plant is dried, you can mount it, save it, or display it!