Culinary Profile
How to grow Elm Oyster at home
Hypsizygus ulmarius, Elm
Updated
Elm Oyster (Hypsizygus ulmarius), also called elm leech, takes about 31 days to grow at home, from spawn to the end of the first harvest. Colonize at 22 °C (72 °F) in the dark, then fruit at 15 °C (59 °F) and 86% humidity with moderate fresh air and 12 h of light a day.
Not a true Pleurotus. Cooler fruiting, meaty single fruits more than oyster clusters.
Use this profile on your chamber
What conditions does Elm Oyster need at each stage?
| Stage | Days | Temperature | Humidity | Fresh air | Light |
|---|---|---|---|---|---|
| Colonization | 16 | 22 °C (72 °F) | 88% | little fresh air: fan runs 15 s every 60 min | Dark |
| Pinning | 5 | 16 °C (61 °F) | 92% | moderate fresh air: fan runs 30 s every 16 min | 12 h a day, white 20%, blue 80% |
| Fruiting | 10 | 15 °C (59 °F) | 86% | moderate fresh air: fan runs 30 s every 14 min | 12 h a day, white 20%, blue 80% |
How long does Elm Oyster take to grow?
About 31 days from the start of colonization to the end of the first harvest window.
- Day 1 to 16: Colonization
- Day 17 to 21: Pinning
- Day 22 to 31: Fruiting
Get dates for each stage from your own start day with the grow timeline calculator, or compare every species in how long mushrooms take to grow.
Light recipe
Dark while it colonizes, then 12 h a day of cool white with some blue.
Light details
Hypsizygus ulmarius is not a Pleurotus. No variety-specific lux was found, so this is the labeled general default, not the oyster production numbers.
WS2812 blue is roughly 465 to 475 nm. The RGB mix is an approximation of cited wavelengths, not a measured spectrum.
| Phase | Hours on | White | RGB mix |
|---|---|---|---|
| colonization | 0 h on | white 0% | RGB 0 / 0 / 0 |
| fruiting | 12 h on | white 20% | RGB 0 / 0 / 80 |
| pinning | 12 h on | white 20% | RGB 0 / 0 / 80 |
What goes wrong when growing Elm Oyster?
No pins after colonization
Make sure the block is fully colonized first. Then check that the chamber reaches the pinning conditions: 16 °C (61 °F), 92% humidity, and moderate fresh air. Pins need more fresh air than colonization. More on this.
Dry, cracked, or curled caps
Usually humidity is too low, or air is blowing straight on the mushrooms. This profile holds 86% humidity while fruiting. More on this.
Green, black, or slimy patches
Patches that are not white mycelium are usually contamination such as green mold or bacteria. Bag the block, take it out of the chamber, and clean the chamber before the next grow. More on this.
Kit or block doing nothing? Work through grow kit not growing. To check your fresh air, put your chamber size and fan into the fresh air planner.
Elm Oyster growing FAQ
What temperature does Elm Oyster grow at?
In this profile Elm Oyster colonizes at 22 °C (72 °F) and fruits at 15 °C (59 °F). Colonization: 22 °C (72 °F). Pinning: 16 °C (61 °F). Fruiting: 15 °C (59 °F).
What humidity does Elm Oyster need?
86% while fruiting. Colonization: 88%. Pinning: 92%. Fruiting: 86%.
How long does Elm Oyster take to grow?
About 31 days with this profile: 16 days of colonization, 5 days of pinning, 10 days of fruiting. Real blocks vary, so move on when the block is ready, not only when the days run out.
How much light does Elm Oyster need?
Colonization: dark. Pinning: 12 h a day, white 20%, blue 80%. Fruiting: 12 h a day, white 20%, blue 80%.
How much fresh air does Elm Oyster need?
Moderate fresh air: fan runs 30 s every 14 min while fruiting. Colonization runs with little fresh air.
Is Elm Oyster good for beginners?
Yes. It is tagged beginner in this library, which means it is one of the more forgiving species to start with.
Related grow guides
- How to grow Beech / Buna Shimeji
- How to grow Beech Shimeji: tight bouquet
- How to grow Blue Oyster
- How to grow Lion's Mane
- How to grow mushrooms at home
- What is the easiest mushroom to grow at home?
- Grow kit vs monotub vs smart chamber
- How much humidity and fresh air do mushrooms need?
- All species and conditions
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Sources
- General default. No variety-specific photoperiod or lux was found for this species. Colonization is dark (Sakamoto 2018; Penn State oyster spawn run). Fruiting uses 12 h as a labeled default, not a page-cited Stamets value, and 20% white, which is 92 lux on this chamber, inside the Penn State oyster 50 to 300 lux band. Blue 80% approximates the 440 to 470 nm finding. This is a labeled default, not a measured value for this variety.
- Sakamoto 2018. Yuichi Sakamoto, Influences of environmental factors on fruiting body induction, development and maturation in mushroom-forming fungi, Fungal Biology Reviews 32 (2018). Light is a fruiting cue for many basidiomycetes. Blue light is the usual photomorphogenesis signal. Agaricus bisporus is called out as not needing light for a cap. Flammulina velutipes can fruit in the dark as a long stem with a tiny cap.
- Stamets. Paul Stamets, Growing Gourmet and Medicinal Mushrooms, Ten Speed Press. Used here as a general cultivation reference. This recipe does not take a photoperiod or lux number from a cited page in that book.