King Oyster Ready-To-Fruit Blocks

King oyster Mushrooms

*Your blocks are meant to be opened immediately for best results. Ready-to-fruit blocks will begin producing mushrooms quickly after arrival at room temperature, but they can be refrigerated up to 3 months prior to opening.

King Oyster ready-to-fruit blocks are meant to be fruited in a controlled growing room and perform best with ideal temperature and humidity conditions. Depending on the size and format of your growing space, you may also need to supplement lighting and provide fresh air for proper mushroom formation. This variety is more challenging that traditional oysters. Due to its nature, King Oyster ready-to-fruit mushroom blocks usually only fruit once so providing ideal fruiting conditions is paramount to success.

Fruiting King Oyster Mushroom Blocks

Setting Up Your King Oyster Blocks:

1) Select a growing space
The growing area should support conditions ideal for mushroom growing. There are several factors: 1) Have indirect sun or supplemental lighting (at least 8-12 hours/day) 2) Temperature control ideally kept 55-63°F 3) Humidity 85% 4) Fresh air exchange. Shelving or other surfaces are ideal for organizing blocks, and the space should be kept clean. Controlling all of these factors will lead to increased mushroom growing success.

2) Setting up your King Oyster blocks
King Oyster mushrooms fruit from the top surface of the block and are sensitive to low or fluctuating humidity during the pinning stage. To open, use scissors to cut off the top of the filter patch bag leaving 2-6˝ of the sides (Figure 1). The remaining bag will form a protected, low air flow, high humidity microclimate around the top of the block to stimulate and support pinning. Place the opened blocks on the shelf in the fruiting room.

3) Maintaining and monitoring
Your grow room should be a controlled area. King Oyster mushrooms require light, humidity, and fresh air to grow successfully. Pins will start developing on the surface of the block 7-14 days after opening. Many pins typically develop, but only the strongest will continue growing to full development (Figure 2). Pin selection is not necessary with this culture. Watch mushroom development closely as they are sensitive to environmental conditions and will indicate if adjustments need to be made in the growing area. The mushrooms will be small-capped and long-stemmed under high carbon dioxide conditions. If this occurs, the sides of the bag can be cut down to allow more fresh air exchange after pins develop. King Oyster is more prone to bacterial contamination than other varieties when the temperatures exceed 65°. This manifests as rust-colored streaking on the stem and discolored patches on the caps of the mushrooms (Figure 3). Avoid direct watering and keep the fruiting area cool and clean to reduce the likelihood of this bacterial problem.

4) Mushroom harvest and storage
King Oyster mushrooms are fully developed and ready for harvest when the cap is almost fully open and flat. If left to over mature, the cap edges will begin getting wavy and release spores. Mushroom quality is better if they are picked before this happens. To harvest, gently grab each of the mushrooms (or cluster) and simply twist and pull them off of the block. Use a scissors to trim the sawdust off of the base. Mushrooms need to be stored in a refrigerator until consumed or sold. A breathable container is ideal for reducing condensation and excessive wetness that will diminish the shelf life.

5) Second and subsequent crops King Oyster is considered a single time fruiting variety. The culture is slow growing and prone to contamination after the initial fruiting. Finished blocks should be tossed onto the compost pile outside and will turn into rich compost over time.

*We only guarantee the first fruiting.
Ready to Fruit Mushroom Blocks are available for discounted prices in larger quantities. All mushroom varieties (Shiitake, Grey Dove Oyster, Chestnut, Lion's Mane, and Reishi) have the same pricing structure and can be mixed. A deposit is due upon order placement. Please inquire if interested.

Time to fruiting:
14-21 days after setup.
Ideal Fruiting Conditions:
55-65°F, 85% humidity
Mushroom appearance:
Large robust mushrooms with thick white stems and medium tan-grey colored caps, decurrent gills, grows individually or in small clusters
Flavor and texture:
Mild, meaty textured
Find the Blocks:

Cut off the top of the filter patch bag to open. Leave 2-6˝of the bag to support mushroom pinning.

king oyster block set up diagram

King Oyster Pins

king oyster mushroom pins

Bacterial contamination (rust colored streaking) on the King Oyster mushroom stem during development.

Bacterial streaking on king oyster