How to make a Spore Print
- Sporeshift Mushrooms Admin
- Aug 27
- 4 min read
Spore prints are an effective method for preserving the genetics of a mushroom strain you want to keep. Like plant seeds, spores carry the genetic material of the parent mushroom and can be stored for years - or even decades - under optimal conditions.
This post will guide you through creating your own high quality spore prints for future use.
Materials Needed
To get started, you'll need these few simple items:
A mature mushroom cap (fresh and open, with gills or pores visible)
Tin Foil (foil works better than paper as it doesn't absorb moisture and the reflectiveness of it makes it easier to see the print)
Knife or scissors
Bowl or something to cover the mushroom cap
Zip Lock Bag
Still air box (optional - makes a cleaner print)
Make sure everything is clean to avoid contamination within the print, especially if you're planning to >> use the print for cultivation later using spore syringes.
Preparing everything to take the spore print only takes a few minutes. Once this is done you will need to leave everything in place for the spores to drop and make your print.
Select a Healthy Mushroom: Choose a fresh, mature mushroom with a fully opened cap, exposing the gills for optimal spore release. The mushroom you select determines the genetics of your spore print, so prioritise quality.
Choose a Suitable Location: Select a clean, flat surface away from direct sunlight and drafts. Ensure the area can remain undisturbed for 12–24 hours. Thoroughly clean the workspace before starting. If you have a still air box, using it to take the spore print will yield a cleaner print that is less likely to contaminate when you germinate the spores.
Prepare the Cap: Using a clean knife or scissors, carefully remove the stem at the base of the cap. Handle the cap gently to avoid damaging the gills, as this can reduce spore release.
Set Up the Print Surface: Place a piece of aluminium foil (roughly A4 size) on your workspace. The foil should be large enough to fully capture the spore print and allow for folding and storage later.
Position the Cap: Place the mushroom cap gills-down in the centre of the foil.
Cover the Cap: Gently place a bowl over the cap to minimise air movement and maintain humidity, ensuring spores fall directly onto the foil and the cap doesn’t dry out.
Spore print underway Be Patient: Resist the urge to lift the bowl for a peek, moving the cap at all will smear the print. Allow the mushroom to release spores undisturbed for 12–24 hours.
Reveal the Spore Print: After 12–24 hours, carefully remove the bowl and lift the cap straight up. If the mushroom was at the right maturity, you’ll see an intricate spore print pattern on the foil.
Agaricus Bisporus (White Button) Spore print showing intricate gill lines. Water splotches visible from cap condensation. Dry the Print: The foil may be damp from the cap’s moisture. Let it air-dry naturally for about an hour to preserve the spore print.
Fold the foil for storage: Fold the foil over the spore print a few times turning it into a flat rectangle. This protects the print from being rubbed and makes it easy to store long term.
You now have a clean spore print!
Spore colours vary by mushroom species, such as the milky white spores from shiitakes. Some prints may appear feint but are still visible to the naked eye on the foil—this is perfectly fine.
If no spore print is visible, the mushroom cap may have been too young to release spores. In that case, place the same cap on a fresh sheet of foil, cover it again, and wait another 12–24 hours. Alternatively, select a more mature cap from your batch and repeat the process.
How to Store a Spore Print
Once you’ve collected your spore print on foil, it’s time to store it properly. Keeping spore prints dry and cool is essential to maintain healthy, viable spores with a high germination rate for future use.
A simple storage method is to place the foil in a zip-lock bag and then double-bag it in another to ensure it stays dry. When stored in a cool cupboard, spore prints can remain viable for over five years, although using them within two years yields the best results.
For longer term storage the fridge is the best option. Avoid storing prints in the freezer as this can damage spores and reduce viability.
When using prints be aware older spores may take longer to germinate. Fresh spores can germinate in as little as 48 hours, while older spores may require 7–14 days. As a general rule, for every year beyond two years of storage, add 1–2 days to the expected germination time.
Further reading
Learn How to use a spore print to germinate spores here >> How to make a spore syringe using a spore print
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