NORTH SPORE King Trumpet Mushroom Grow Kit Fruiting Block

Out of stock
Regular price $30.00

NORTH SPORE King Trumpet

Mushroom Grow Kit Fruiting Block

King Trumpets (Pleurotus eryngii) produce large flushes of meaty, 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 savory umami flavor, a soft, crunchy texture, and a mild 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. They also do not reliably produce second flushes, but may if temperature and humidity conditions are well controlled.

Skill level


Grow location


Grow speed

2 to 3 weeks

Shelf life

6 months (refrigerated)

Flavor profile

Savory, meaty, earthy

Kit dimensions

6in H x 9in W x 6in D

Kit weight

5 lbs


1). Your king trumpet fruiting block kit is an amended sawdust block that has been completely colonized by mycelium. Before opening your bag at all, you should observe your block closely through the plastic. You want to watch for the development of baby mushrooms (also called 'pins' or 'pinsets').

2). Once your block has developed pins, you want to cut around the circumference of the bag one to two inches above the block while leaving a two-inch section uncut. This should allow the bag to form a clamshell-type enclosure around the block. You should be able to both cover the block with the bag and pull it back to reveal the block to the open air.

3). The king trumpet needs proper humidity and ventilation to survive. They especially love colder locations. Place your sliced block in your BoomRoom or the most humid part of your home and away from direct sunlight. \We suggest putting your bag on a kitchen counter somewhat close to a sink. The top of the bag that can clamshell open or closed will act as a humidity tent for your block. Think of it like maintaining a terrarium. Keep in mind that mushrooms exhale CO2 and inhale oxygen. They will suffocate themselves if there isn’t adequate airflow!

4). Harvest your king trumpet mushrooms when they resemble the photos on this page! Harvest before the caps flatten out and become concave. They grow quickly, so when you spot your first mushroom pins, keep a close eye on them. The warmer the environment, the faster they will grow. King trumpet mushrooms should be ready to harvest three to seven days after pin formation.

Second flushes are somewhat difficult with king trumpets, but give it a try! We recommend giving your block a one-week break between fruitings. Simply leave it alone on your kitchen counter, soak your block in cold water for 20 minutes after one week, drain any water that may have become caught in the bag, and then restart the process of spraying your blocks with water daily.

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Temp, Humidity & CO2 guide

Fruiting temps

55-65 degrees F



CO2 Sensitivity

<2,000 ppm

  • Fruiting - The phase of growth in which visible mushrooms begin to appear.
  • 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.


If you don't plan to use immediately, you can refrigerate your block for up to 6 months.


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.


Spawn used in our fruiting blocks is grown on USDA certified organic grain and made with organic cultures from our own culture bank. Our fruiting blocks are handmade from a blend of locally sourced, all-natural, organic, and non-GMO woods and supplements from farms and forests in New England and North America.

Creating a humidity tent:

If your home is very dry, and you do not have a humidity-controlled grow chamber, you may need to make a humidity tent to place over the over fruiting block. To do this, find a loose-fitting plastic bag and make plenty of ½-inch holes all over it. Then place it over the fruiting block (that is still inside it’s original bag.) Once you’ve made the humidity tent, be sure to spray the inside of it a minimum of once per day.

Cautions & Considerations:

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.

Mushrooms grow spores as they develop. This is a natural means of reproduction. This is when people with allergies or compromised immune systems may want to consider putting fruiting mushroom kits outdoors or in a well-ventilated area. Spores in mushrooms sometimes cause respiratory irritation. In rare cases, spores may also cause irritation for some non-allergic or non-immunocompromised mushroom growers. If you are one of them, it is recommended to reduce the overall spore load by harvesting mushrooms while they are still in their younger growth stages.


Customer Reviews

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Returning customer and had follow-up phone call