It is always a good idea to keep some spores on hand for your favorite species in case something happens to your agar cultures, such as the fridge you store them in breaking down while you're away, or culturing a specimen to the point of senescence. Spores are like a genetic reset button that will allow you to test for genetic mutations, and find high yielding substrains of the species you are working with. Mushroom spores are tough, and can even be germinated after being exposed to the vacuum of space! Spore printing is also easy, and prints take up very little room.
The first step in spore printing is choosing a mushroom that is about to begin dropping spores. Once you have selected a mushroom to print, you will need the following supplies:
1 craft knife or set of surgical scissors
1 roll of aluminum foil
1 shallow Tupperware container with tight fitting lid (sandwich containers and cake containers are perfect)
Cut a piece of foil so that it is an inch wider than the cap of the mushroom, and twice as long. Place the piece of foil in the container.
Harvest the mushroom, and cut the stipe off as close to the gills (or pores depending on species) as possible. Be gentle, you don't want to damage the gills.
Place the mushroom gills down on the foil, and put the lid on the container.
Wait 24 hours while the spores drop, be sure to turn off any fans or air conditioning at least 1 hour before proceeding with the next step.
After 24 hours, remove the mushroom cap from the foil. You should have a thick layer of spores on the foil, allow any moisture to evaporate off of the print. Fold the foil in half over the spore print, and fold the edges over, then label the print with the date and species.
Place the print in a plastic bag. Prints store best in a fridge, but can be stored at room temperature as well. Spore viability does reduce over time, but will remain usable for several years (while it was difficult, spores have been successfully germinated and cultured after being stored for over 20 years).
USING A SPORE PRINT
You can use a spore print by simply scraping spores off the print onto agar (you don't need much, a small fleck is sufficient. If you can barely see the spores that dropped onto the agar, you've got more than plenty there), or you can make a spore syringe. To make a spore syringe, you'll need the following supplies:
a sterile syringe
a sterilized shot glass
a jar of sterile water
a sterilized butter knife
This procedure can be done in open air. The reason for sterilizing the tools is to help ward off bacterial contamination. The reason for wearing rubber gloves is to prevent bacteria on your hands from getting onto the print or tools. Use boiling water to sterilize your tools.
Use the syringe to put a few drops of the sterile water onto the print. You don't need much, 1 light print contains millions of spores and can make 10 to 20 syringes with ease. Squirt some of the water into the shot glass as well.
Use the sterilized butter knife to loosen some of the spores from the print, then tip the print over the shot glass to add the spore laden water to the shot glass. Use the syringe to stir up the water, draw it in, squirt a little back into the glass, and pull it back in. You should now have a spore syringe with spores visibly suspended in the water. A syringe with spores visibly suspended can be ejected into a glass of sterile water to be expanded into more diluted syringes. Just because you can't see spores in the syringe does not mean they aren't there! Individual spores are microscopic, a single visible fleck of spores is made of thousands of spores.