Frequently Asked Questions
About SpawnHow long is spawn good for?
If refrigerated, grain and thimble spawn -2 months, sawdust spawn - 4 months, plug and peg spawn- 6 months. Exceptions (cannot be refrigerated): Pink Oyster (1 month) and Almond Agaricus (up to 1 year). Click here to read our Spawn Storage sheet.
What can I do with left over spawn?
Best to use it up! Heavily inoculate remaining substrates (wood chips, straw, etc.) or even go back and add inoculum to logs. You will probably get faster fruiting from substrates with the addition. Or, if you have extra plugs or sawdust following a spring inoculation, refrigerate the remaining spawn in its original filter patch bag and use it in the fall. With leftover grain spawn, you should use it promptly - consider using it to make your own TeePee™ rolls. Grain spawn can also be used for totem method log inoculation.
Do I have to use all of the grain spawn in a bag right away?
No. Keep the leftover spawn in the original filter patch bag and fold the bag securely into a packet, but use promptly to avoid contamination and drying.
My sawdust spawn is white on the outside but brown inside. Is it fully colonized and can I use it?
This is completely normal. Overtime sawdust spawn will develop a tough white outer casing due to exposure to fresh oxygen through the filter patch. The interior of the spawn, although showing very little white, is still fully colonized and can be used immediately upon receiving. Massage the contents of the bag and use both exterior and interior spawn for your inoculation.
Why doesn't my spawn look like it did the last time I ordered it?
Spawn is sent out to our customers at various stages, but it always leaves our facility fully colonized and ready to use. Spawn that is aged longer at our facility can develop thick white mycelium (that bunches up or "ropes" in sawdust spawn), whereas younger spawn only has a lighter mycelium. Keep in mind, this does vary by species, as some have completely different looking mycelial growth. As spawn grows, it begins to break down the substrate it is growing on, resulting in a yellow fluid that can collect at the bottom of the spawn bag and/or small patches of brown on the exterior of the spawn. These are all normal characteristics of spawn.
I just received my Pink Oyster grain spawn and it doesn't look colonized. Is it dead?
No, the spawn is not dead. The mycelium of the Pink Oyster is much lighter and delicate than our other oyster varieties. Often times these bags never colonize thickly. If this finer mycelium is disturbed too much in transit, it "disappears" from the outside of the grain. However, the grain is still fully colonized and should be used within a month of receiving. Remember, do not refrigerate Pink Oyster spawn! You should not wait for the Pink mycelium to regrow because often times this does not happen - the quick, aggressive nature of Pink mycelium has already utilized all it can from the outer part of the grain and doesn't need to go back for seconds.
Can I freeze spawn?
Logs for Mushroom Growing
What kind of logs do I need for growing mushrooms?
General rule of thumb: hardwoods for most mushrooms, but soft hardwoods (aspen, box elder, tulip poplar, etc.) for the Oyster mushroom group. Click here to view our Tree Species Suitability Chart.
When should I cut the logs?
Dormant season is best (fall through early spring). Click here to view our Timing Your Wood Harvest Chart.
How long can logs sit before inoculation?
A minimum of 2 weeks and a maximum of 6 months, depending on when they're cut, local environment, and tree species.
I have heard that logs are soaked, what does that mean?
"Soaking" is the same process (dunking logs in cold water for 12-24 hours) but refers to one of two different purposes, depending on when it is done. Soaking logs before inoculation refers to adjusting log moisture content prior to inoculation (avoid this if possible because it is another labor step!) Soaking during fruiting phase is done to stimulate fruiting (this only works well for Shiitake logs), and is also referred to as "forcing."
How do I know if my logs sat too long before inoculating?
Logs are at nearly optimal moisture content around 40-45% when cut, but must then begin the drying process for about 2 weeks. Cracks on the log ends are natural indicators of a log drying and can be helpful in judging its moisture content. Logs with deep cracks on the ends may be too dry (less than 30% MC).
Do I need to soak logs before plugging?
Logs that have cracks on the butt ends greater than 1mm or have thin bark and seem light and dry will benefit from a 24-hour soak prior to inoculation. Fresh cut wood storing for 6 -8 weeks or less under cool conditions will not need soaking.
When should I inoculate my cut logs?
General rule: Fall cut logs: 2 weeks after felling up until daytime highs regularly are below 50°F. Winter or early spring cut logs: inoculate from when you can work comfortably outdoors with bare hands, up until daytime highs regularly surpass 70°F.
Can I plant different strains into one log?
Not recommended. Strains are antagonistic to one another, even within a group of mushrooms.
How do I sharpen my screw tip mushroom bit when it becomes dull?
You can sharpen bits yourself using a flat file. Look for an upcoming video demonstrating the appropriate technique. Meanwhile, professional sharpening may be in order.
Won't hot wax kill the spawn?
Wax temperature drops immediately when it hits the thin film of water on the spawn, resulting in a complete seal with no harm to the spawn.
Can I over inoculate?
No. Commercial growers will want to adjust inoculation rate to their climate to achieve excellent spawn run and minimize inoculation costs. Newer growers can benefit from "over" inoculating; and will be rewarded with faster fruiting.
Log Incubation after Inoculation
How should I stack my logs after inoculation?
Stack logs so that they receive plenty of moisture but not enough to allow green molds to become established on bark surfaces. Drier climates (Midwest, NE, and western states) benefit from low stacks (logs laid on pallets or rails in the shade) or low log cabin (crib) stacks. Wetter climates (the SE) benefit from waist-high crib stacks.
In the late spring and early summer, a black rubbery fungus shows up on my newly inoculated logs. What should I do about this?
This is a species of Bulgaria which is taking advantage of available simple sugars in the bark. It will dry up, disappear and not be a threat to Shiitake.
On my newly inoculated logs, the sawdust spawn has disappeared and the holes are empty. What caused this?
If the holes are on the exposed tops and sides of the logs, chances are it was woodpeckers enjoying a lip wax job. Cover the logs with a porous material such as evergreen boughs, burlap, or old bed sheets to form a barrier to keep them off. Spawn missing from unexposed holes on the bottom of the logs may be the result of slugs. Slugs are more difficult to control but spreading diatomaceous earth around the logs will form a physical barrier to new slug arrivals. This is also recommended to help keep slugs off of fruiting logs.
I have worms in the stems of my Oyster mushrooms. What can be done to prevent this?
These worms are the larval stage of the picnic beetle which is widespread and commonly found in mushrooms. It is difficult to control. A physical barrier such as a floating row cover covering the logs may prevent the beetle from getting to the logs.