Instructions – Oyster

Oyster Mushroom (Pleurotus sp)

NOTE: Your kit may say “GR”, “FP”, “BL”, “PO”, “KKO”, or “SCT2” on it. All are normal and are oyster varieties.

Congratulations on your purchase of an oyster mushroom growing kit! If you already have a tabletop humidity tent or mini-greenhouse you can use that, otherwise something can be easily improvised (or try without if it’s humid.) At home I use a 4-tier mini greenhouse that I picked up pretty cheaply.

A humidity tent is not required, but may be helpful if the air is dry in the growing area.

You will need:

– your spawn block

– a clear plastic bag or clear plastic over a frame for humidity (optional)

– a very sharp knife

The simple version:

  1. cut four 2″ vertical slits across “front” of bag (it’s ok if some of the sawdust gets scraped)
  2. mist regularly
  3. adjust humidity tent for local conditions (cut more or less air holes)
  4. wait for mushrooms

The spawn block is composed of pelletized hardwood sawdust and various organic supplements such as wheat bran, held together by the white mushroom mycelium. It is ready to fruit when you receive it, although if put somewhere cool and dark it will likely wait for up to a week or two. When you’re ready, wash your hands, wash a sharp knife, and cut four evenly spaced 1.5-2″ vertical slits across the bag, over the sawdust.  Try not to cut the block as much as possible. Also try not to cut so high on the bag that it would expose the top to air – it may help to tape the top of the bag down.

These cuts are where the mushrooms will grow from.

If you spot tiny mushroom clusters already growing on top of the block, you can cut slits in the bag right above them to let them out. Don’t make too many cuts or you may lose too much humidity. If you decide not to harvest the top fruits, try to keep any more air from getting to them.

Put the humidity tent loosely over the block, which you may need to prop up with wire hangers or other supports poked into the block. Mist it occasionally but do not over-water. Putting a dinner plate under the block can help to control water that may leak out. The mushrooms also need fresh air, or the fruits will be small and thin, but the humidity tent should provide that. If you notice thinner fruits with long stems and small caps, you should enlarge the holes in the humidity tent slightly. The humidity tent should give 4-6” of room for the mushrooms on every side of the block. Cut holes in the humidity tent as necessary – I’d suggest cutting a dozen 1/4″ holes to start. You may need more or less based on ambient humidity.

Your mushroom kit requires nothing more than room temperature (not too warm), indirect light, and a bit of extra humidity.

Note: Some mushrooms prefer warmer or cooler growing conditions. King oyster prefers cool temperatures, pink and other oysters generally prefer more moderate conditions.

After 5-7 days (don’t panic if it takes a little longer) you should see small clusters of tiny mushrooms begin to grow around the slits in the bag. These will grow into full sized mushrooms in another five days or so and should be picked with a clean sharp knife when mature (but before the cap begins to turn upwards.) Make sure not to spray mist directly on the mushrooms.

When the block stops producing mushrooms, you can dunk it for several hours in cold water if it looks dry (be sure to drain it) and repeat the process. If it doesn’t look or feel dry (it can pull away from the sides of the bag when dry), just keep caring for it and it’ll fruit again in a week or two. You may get up to 3 harvests, although they tend to get smaller.

If the block develops heavy colourful mold or bacteria (which is rare when kept in a clean environment), do not eat the fruits from it after that point and dispose of it away from other mushroom projects. This happens more frequently with blocks at the end of their lives. Due to the possibility of non-harmful but unsightly fungus gnats, it is not recommended to keep the block in the same greenhouse as potted plants.

If contamination develops, go here for tips!

If you have any problems or questions, please don’t hesitate to e-mail!

Mushroom growing can be challenging and while, due to the number of factors involved in getting a successful harvest, we don’t offer a guarantee, help is most certainly available.