How long do mushroom spores last?
Great question! Like most things in mycology, the answer is “it depends.” Different species vary a bit, but in general, spores can remain viable for years if stored properly. That means keeping them sealed, in a dark, dry, cool location such as your fridge.
Spore syringes don’t last quite as long since the spores are suspended in water. You’ll typically get about 12 to 24 months out of a syringe, but I’ve found they typically do best if used within a year.
If spores are left at room temp or exposed to light or moisture, their shelf life can drop off pretty fast, usually around the 3 to 6 month mark in my experience.
In this post, I’ll break down what affects spore viability and how to store prints, swabs, and syringes so they stay good as long as possible.
What affects spore viability?
The three main factors that affect shelf life are light, temperature, and humidity.
Light
Spores don’t love the spotlight, especially UV light. It can mess with their internal structure by breaking down delicate compounds like DNA, RNA, and proteins. In nature, spores are often protected by pigmentation or structural barriers, but once we collect them, those defenses are gone. That means it’s up to us to keep them safe and out of the light.
Temperature:
Heat speeds up the natural aging process of spores and increases the risk of contamination. On a molecular level, higher temperatures accelerate chemical reactions, which can denature proteins, damage membranes, and disrupt the enzymatic systems spores need to germinate. Even if they look fine on the outside, too much time in a warm environment can quietly break down their internal structures.
Temperature
Warm temps speed up the natural aging process of spores and open the door for contamination. On a microscopic level, heat accelerates chemical reactions that can damage proteins, membranes, and enzymes — all the stuff spores need to germinate. Even if they look fine, too much time in a hot environment can quietly break them down from the inside out.
Humidity:
Spores are designed to remain in a dry, dormant state until conditions are right for germination. Even a small amount of moisture can trigger premature metabolic activity, leading to cellular stress and degradation. On top of that, moisture invites bacterial and fungal contamination, which can show up as clumping, discoloration, or visible mold.
Ideal Storage Conditions
Whether you’re working with spore prints, swab sets, or syringes, the same general rules apply:
- Keep them away from light: Wrap your spores in foil or use UV-resistant bags, and store them somewhere dark.
- Keep them cool: Store in a temperature regulated environment (such as your fridge), between 36°–42°F (2°–5.5°C).
- Keep them dry: Airtight packaging is important, especially if you live somewhere humid. You don’t need to vacuum seal them, but removing excess air before sealing makes a big difference.
If you’re managing a small personal library, storing them inside the produce drawer of your fridge works great. If your collection is starting to grow and you need more space, a mini beverage fridge is an excellent upgrade!
Since each product type varies in material and packaging, I’ll go over the nuances below.
How to Store Mushroom Spore Prints
If you purchased your spore prints from me, they’ve already been wrapped in sterilized foil and placed in a bag, so all you need to do is find a sturdy container to store them in before placing them in your fridge so they don’t get damaged.
If your library is small, you could just use a box but if it’s starting to grow, a Trading Card Binder is really helpful to stay organized.
If you took the prints yourself or received them unwrapped, just make sure to wrap them first. This not only protects them from light but also keeps spores from sticking to the inside of the bag.
To sterilize your foil, just spray some iso on a paper towel and wipe down both sides inside a SAB or in front of your flow hood.
Tip: Use aluminum foil thats at least 30 microns thick (I love this brand here), and then cut the pieces large enough to easily unwrap and rewrap the print with gloved hands.
How to Store Mushroom Swab Sets
Since swab sets often come in a package with one clear plastic side, I like to store them in 6” x 9” UV resistant poly bags to protect them from the light. Then same as the spore prints, place the bag inside a sturdy container and store them in your fridge.
Tip: Heat sealing your swab sets instead of taping them makes it so much easier to open and reseal without damaging the packaging. If you don’t have a heat sealer, Scotch Delicate Surfaces Painters Tape is a lot easier to peel off than other brands.
How to Store Mushroom Spore Syringes
I store my spore syringes just like I do swab sets, inside 6” x 9” UV resistant poly bags that I place in a sturdy container before storing in the fridge.
Tip: Once a syringe has been used, I like to spray needle with iso before placing the cap back on to keep it clean.
FAQs
Q. Where’s the best place to store mushrooms spores?
In a dark, dry, temperature regulated environment like your fridge.
Q. How long do mushroom spores last?
Prints and swabs can last for years if sealed and stored in the fridge. The shelf-life of a syringe is a bit shorter since the spores are suspended in water. Typically 12-24 months.
Q. What temperature is best for storing mushroom spores?
The ideal temperature to store mushroom spores is between 36°–42°F (2°–5.5°C). This range works well because its cold enough to slow degradation without running the risk of freezing.
Q. Can you freeze mushrooms spores?
No. They might survive a single freeze, but ice crystals can form and damage the spores, especially if there’s moisture present. Repeated temperature swings, like freezing and thawing, can drastically reduce viability too. It’s best to keep them a few degrees above freezing.
Q. Should I use a silica pack with my spores?
No. As long as you squeeze out excess air before sealing the bag, there’s no need to include a silica pack. In fact, adding silica packs can dry things out too much and cause the spores to crumble and flake off the foil.
Q. Does oxygen degrade spores?
Yes, but slowly. Over time, oxygen can contribute to spore degradation, but it’s more of a slow, indirect process compared to light, heat, or moisture. As long as you squeeze out excess air from your bag before sealing, there’s no need to include an oxygen absorber (although it couldn’t hurt).
Q. How do you know if mushroom spores are still viable?
Unless you see visible contamination like mold, there’s really no way to know for sure just by looking at them, especially with prints or swabs. The best way to check viability is to observe spore activity under a microscope, or if you live in a place where cultivation is legal, attempt germination.