Organic King Trumpet Mushroom Grain Spawn












Skill level | Intermediate |
Grow location | Indoors |
Spawn shelf life | 4 months (refrigerated) |
Certifications | USDA certified organic |
Bag weight | 6 lbs |
Fruiting temps | 50-65°F |
Our USDA-certified organic king trumpet (Pleurotus eryngii) grain spawn features a strain that produces large flushes of meaty and delicious mushrooms that are earthy, aromatic, and savory. Raw king trumpets, though dense and spongy in texture, lack aroma and flavor. But when cooked, they come to life with a soft crunchy texture and a mild savory umami flavor reminiscent of abalone.
Unlike other oyster varieties, king trumpets can be more difficult because they prefer cooler temperatures and are prone to drying out or stopping their growth if humidity is not maintained in the early stages. Additionally, King trumpets do not reliably produce second flushes, but may if temperature and humidity conditions are well controlled. Therefore, they are recommended for more advanced growers.
“5 of the Best King Oyster Mushroom Recipes”
Recommended use:
- King trumpet grain spawn can be used for indoor production using sawdust-based sterile substrate.
- Do not use grain spawn for log inoculation.
- This is not a mushroom grow kit. King trumpet grain spawn must be combined with a substrate in order to fruit.
Upon receiving your spawn:
Remove it from the shipping box as soon as possible. Then, unfold the top of the bag, making room for air space. It's also important to check and confirm that the filter patch is not obstructed. This will help the organism breathe and continue to thrive!
Scroll down for specifications, growing, and storage guides.
-
- Weight: Approximately 6 lbs
- Hydration: Average of 47%
- Bags: Gusseted 2.2 mil polypropylene
- Filter: High efficiency .2 micron
- Inoculation Rates: 6 lb. bag of grain will inoculate between 120-165 lb. sterilized sawdust, and 100-130 lb. pasteurized straw
- Sterilization method: Commercial grade autoclave sterilized
-
Temperature 50-65°F | 10-18°C Humidity (Phase 1: Primordia) 95-100% Humidity (Phase 2: Fruitbody) 85-95% CO2 Sensitivity (Phase 1: Primordia) High CO2, keep in bag CO2 Sensitivity (Phase 2: Fruitbody) <2,000 ppm - Primordia - The earliest recognizable stage of fruitbody development. Also known as “baby mushrooms” or “mushroom pins.”
- Fruitbody - A fully grown mushroom, the reproductive structure of the organism in which the spores are produced.
- CO2 sensitivity - When CO2 levels are too high, yields will decrease, stems will become long and stringy, caps will be small, and/or growth will halt.
-
King trumpet mushroom grain spawn can be mixed into sterilized hardwood sawdust to create king trumpet substrate blocks.
Note: Grain spawn must be mixed with bulk substrate before you can fruit it. If you are new to growing mushrooms, we recommend purchasing a book on mushroom cultivation.
Recommended reading:
'Growing Gourmet and Medicinal Mushrooms' by Paul Stamets
'Organic Mushroom Farming and Mycoremediation' by Tradd Cotter
-
If you don't plan to use immediately, you can refrigerate your spawn for up to 4 months.
-
"5 of the Best King Trumpet Mushroom Recipes"
King trumpet mushrooms are one of the meatiest oyster varieties and make a great substitute for meat. However, unlike the thick king oyster mushroom, king trumpets have a shorter stem and a larger cap that fans out when fully grown. They are delicious when marinated and grilled and their mild yet savory flavor lends well to many different recipes. When thinly sliced, they will sear nicely in a pan.
-
Our grain spawn is USDA certified organic and made using organic cultures from our own culture bank. It contains a blend of locally sourced, organic, and non-GMO ingredients from farms in New England and North America.
-
If you’re going to consume home-grown mushrooms, make sure to cook your fresh mushrooms thoroughly with heat. If it is your first time eating this species, it is best to start with a small amount to check for allergies, even if cooked.
You may also like
- Reviews
- Questions
Thank you for submitting a review!
Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Quick colonization
Easy mixing! The spawn quickly colonized wood sawdust blocks fully in 14 days and I'm looking forward to some giant kind trumpets!

Good Grain
So far so good. This King trumpet grain spawn is aggressive and spread through my sawdust blocks very well. Still haven't tried the mushrooms yet but I'm sure they'll be delicious. Now where's my free shirt?
North Spore
Thanks for the review. You can write into us and let us know your size and shipping address at info@northspore.com

Best Customer Service and Quality Product
Very upfront and honest about how long your product will take to be delivered. Products (I purchased 9 different strains of grain spawn) all arrived in great condition, healthy and showing active growth. In addition to that, I've received great customer service for a multitude of questions, both about the products I've received and mycology in general, quick and to the point while being courteous and making sure the answers are specific to my question. Probably won't use anyone else in the future, as other brands have been more difficult and less reliable to work with.

Black King grain spawn
Ordered several bags of black king grain spawn. On arrival, the spawn was fully colonized and looked great. Inoculated many bags of sawdust spawn which are currently incubating and doing fantastic! Highly recommend North Spore for their quality and selection!

Blue Oyster grain spawn
My grain spawn arrived pretty fast and in perfect condition! I’m really impressed by the quality and will be buying again.

Right on time
I have purchased many different grain spawn strains from North Spore. They never disappoint. The shipment always arrives sooner than I would expect, and the bags are almost always perfectly ready to either store when ready, or transfer to substrate. The quality of the mushrooms are maintained at a high level. Always Gen. 2. I operate a small mushroom farm in Florida, and North Spore is a great resource for commercial or hobby products.

GREAT EXPERIENCE!
We have had nothing but an amazing experience with this and all other types of grain spawn that we have order from your company. Shipping is fast and our mushrooms are beautiful! Keep up the awesome work; we appreciate you! Sienna Wolgast Wolgast Mushrooms
Fast
I ordered this spawn and it was at my place in less than 3 weeks. Spawn arrived looking well colonized and clean. Great product!
Great Spawn
I recently changed to North Spore for the spawn I use on my mushroom farm. I have used spawn from other companies and have made my own spawn with great success. The spawn at North Spore is AMAZING! My bags are fully colonized in 2 weeks. I'm having to expand my grow room just to make more space because I'm not used to them colonizing this fast. Great Spawn you have doubled my weekly sales!
Perfectly Colonized Grain Spawn
Not much more you could ask for, well colonized and great looking bag of grain spawn.