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Image by Kevin Grieve

King Oyster Mushroom kit Growing Instructions

King oyster mushroom is the largest species in the oyster mushroom genus. King oyster mushroom grows slower than oyster mushroom, and it has a thick, meaty white stem and a small tan cap. This kit is very easy to set up. You may place the kit on a coffee table, counter, or desk - it will produce mushrooms virtually anywhere in your home or office with enough light and room temperature (55°F~75°F).  Now you have the opportunity not only to enjoy watching these exotic mushrooms growing but also to enjoy eating the freshest mushrooms possible.


Remove the tape from the shrink wrap at one end of the log and pull the wrap open just enough so that the end of the mushroom soil is exposed. DO NOT remove any of the shrink wrap material.


Using the small mist bottle, mist the open surface of the log, and the inside of the humidity tent. Then, place the log back into the product box with flaps tucked in. The misted end of the log should be at the open end of the box. Place the misted humidity tent over the box by pulling the open end of the tent down as indicated in the figure below.


OR, you can set the log directly on a dish or plate without the box, and cover the log with the humidity tent.

Please be sure to mist both the exposed end of the log and the inside of the humidity tent at least twice a day, using the spray bottle supplied. In about 7-10 days, it should start sprouting.



When the mushrooms are about 1inch high, cut the open end of the bag that surrounds the log as close as you can to the surface of the mushroom soil and remove that top part of the bag ONLY.  When the mushroom cap edges are becoming flat (about 8 days after sprouting, carefully pull off all mushrooms, and prepare your kit for its next flush.

Once you cut your mushroom bag open and set your kit in an ideal location, try not to move, shift, or jiggle the kit. Doing so may delay the fruiting of your mushrooms.

Growing Conditions

Temperature: 55°F~75°F. To initiate the germination of your mushrooms, keep the log exposed to fresh air and in a low temperature (60-68 °F) for at least 4-5 hours a day until you see mushrooms.

Light: Oyster mushrooms need light to grow, but do not expose your kit to direct sunlight. A normal level of indoor light is sufficient.

Water: The log already contains enough water, so do not water it. As long as there are condensation droplets on the inside surface of the humidity tent, you do not need to spray.  If there are no condensation droplets, please spray. However, AVOID OVERWATERING the surface of the log. If there is any water visibly pooling on the log, please remove it. In~7days, you should be able to see mushrooms growing. Once mushrooms start to grow, please do not spray the surface of the log or the baby mushrooms. (Otherwise, they will become withered.) Simply keep the humidity tent moist with condensation droplets.

Control mushroom number: Limit each flush to only 3-4 mushrooms in order to get the best results out of your kit.  When the mushrooms are about 2 inches, thin them out using a knife carefully to cut any mushrooms that you do not want to keep. Of course, you can keep all the mushrooms if you want, but this will limit their size.

CO2 level:  The levels of CO2 greatly affect the shape of the fruit bodies. Grown outdoors or in a grow room with high air exchange the stems will be short and caps will be large. With higher concentrations of CO2 from low air exchange the fruits will develop thick long stems with small caps.

Get Ready For Your Next Flush

This kit can give your multiple flushes (batches) before it is exhausted. Each time, after you pick up all mushrooms:

  • Use a fork to scrap away the top layer of the log to remove any leftover mushrooms and stems.

  • Soak the whole log with the plastic wrapping still intact in water overnight (use a weight to keep the open end of the log under water).

  • Remove the log from underwater and drain any excess water, then use any plastic bag you have (like from a grocery store) to wrap the log completely. Place the log back into the box, close the box, and leave the log inside. Place the box in a dark place for 7 days.

  • After 7 days, open the box, remove the plastic bag you placed around the log (not the original plastic wrapping, which should always be kept with the log). Spray the open surface of the log and the inside of the humidity tent as before. Please note that you might see some white fuzzy stuff growing on the surface of the log, this is mushroom mycelium, not mold. Do not try to clean it off or discard the log.

  • Enjoy another growing flush!

Image by Beth Macdonald

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