Shiitake
Lentinula edodes · WR-46 · v2.0.0
The long crop. Eight to twelve weeks of colonisation before anything happens, then a browning phase that most first-time growers mistake for contamination and throw away. Lower humidity than oyster — over-humidifying shiitake causes rot, and the instinct to push RH to 92% is the commonest way to lose a block.
Spawn run
Advances after 42 days, or when you say so| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 24.0 °C | 23.0 °C – 25.0 °C | heater, cooler |
| Relative humidity | 80.0 % | 77.5 % – 82.5 % | humidifier |
| Carbon dioxide | 6,000 ppm | 4,750 ppm – 7,250 ppm | exhaust, intake |
| Light | dark | — | lights |
| Fresh air, minimum | 0.3 changes/hour | — | exhaust, intake |
Six weeks minimum, and eight to twelve is common. There is no way to hurry this and every attempt costs yield.
Vapour pressure deficit at these targets: 0.60 kPa. That is what 80% humidity means at 24.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Browning
Advances after 14 days, or when you say so| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 21.0 °C | 20.0 °C – 22.0 °C | heater, cooler |
| Relative humidity | 75.0 % | 72.5 % – 77.5 % | humidifier |
| Carbon dioxide | 1,500 ppm | 1,200 ppm – 1,800 ppm | exhaust, intake |
| Light | 12 h at 500 lux | — | lights |
| Fresh air, minimum | 2.0 changes/hour | — | exhaust, intake |
The block forms a brown skin. This is the crop working, not a contaminant. Light and fresh air drive it; humidity comes down to let the skin set.
Vapour pressure deficit at these targets: 0.62 kPa. That is what 75% humidity means at 21.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Cold shock
Advances after 1 days, or when you say so| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 12.0 °C | 11.0 °C – 13.0 °C | heater, cooler |
| Relative humidity | 88.0 % | 86.0 % – 90.0 % | humidifier |
| Carbon dioxide | 1,200 ppm | 950 ppm – 1,450 ppm | exhaust, intake |
| Light | 12 h at 500 lux | — | lights |
| Fresh air, minimum | 2.0 changes/hour | — | exhaust, intake |
Twelve to twenty-four hours cold, traditionally with a soak. The shock is the fruiting trigger for this species.
Vapour pressure deficit at these targets: 0.17 kPa. That is what 88% humidity means at 12.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Fruiting
Advances after 7 days, or when you say so| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 16.0 °C | 15.3 °C – 16.8 °C | heater, cooler |
| Relative humidity | 85.0 % | 83.5 % – 86.5 % | humidifier |
| Carbon dioxide | 900 ppm | 725 ppm – 1,075 ppm | exhaust, intake |
| Vapour pressure deficit | 0.27 kPa | 0.23 kPa – 0.32 kPa | humidifier, in advanced mode |
| Light | 12 h at 600 lux | — | lights |
| Fresh air, minimum | 4.0 changes/hour | — | exhaust, intake |
85%, not 92%. Shiitake caps crack decoratively at a slightly higher deficit and that cracking is what the premium grade is.
Vapour pressure deficit at these targets: 0.27 kPa. That is what 85% humidity means at 16.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Harvest
Advances when you mark "harvested", or after 3 days| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 16.0 °C | 15.3 °C – 16.8 °C | heater, cooler |
| Relative humidity | 82.0 % | 80.0 % – 84.0 % | humidifier |
| Carbon dioxide | 1,000 ppm | 800 ppm – 1,200 ppm | exhaust, intake |
| Light | 12 h at 600 lux | — | lights |
| Fresh air, minimum | 3.5 changes/hour | — | exhaust, intake |
Pick when the cap is still curled under. Flat caps have already dropped most of their spores and most of their price.
Vapour pressure deficit at these targets: 0.33 kPa. That is what 82% humidity means at 16.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Rest and re-soak
Advances after 14 days, or when you say so| Signal | Target | Band | Switches on |
|---|---|---|---|
| Air temperature | 21.0 °C | 20.0 °C – 22.0 °C | heater, cooler |
| Relative humidity | 78.0 % | 75.5 % – 80.5 % | humidifier |
| Carbon dioxide | 2,000 ppm | 1,600 ppm – 2,400 ppm | exhaust, intake |
| Light | dark | — | lights |
| Fresh air, minimum | 1.0 changes/hour | — | exhaust, intake |
Two weeks to recover, then soak the block in cold water overnight to re-trigger. Blocks give four to six flushes over five or six months.
Vapour pressure deficit at these targets: 0.55 kPa. That is what 78% humidity means at 21.0 °C — the figure the crop responds to, and the one a hygrometer cannot show you.
Alarms
These do not switch anything. They sit outside the control loop deliberately, so that a bug in the control logic cannot also silence the thing that wakes you.
- Air above 30 °C
- Air below 8 °C
- Humidity below 65%
- CO2 above 4,000 ppm
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A room review sends about 2,000 tokens and gets back about 600 — roughly US$0.03, or under three rupees.
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These targets are derived from published literature, not measured on your substrate, your strain or your room. Treat any recipe you have not validated on your own farm as a hypothesis. The yield log exists so that your second run can correct your first. Literature-derived. Not yet validated on a farm.