Mushrooms, held to a number.
A grow room is four measurements and six switches. What makes it hard is that the switches fight each other — ventilating to drop CO2 also strips the humidity, and two independent control loops will oscillate until the crop is ruined. This is the recipe layer, the arbiter that resolves that fight, and a room simulator that lets you find out whether your fan and your fogger are big enough before you buy them.
Nothing on this page is in the control loop
The node
A board in the room holding its own copy of the recipe in flash. It runs the stage machine and every control loop on its own, and keeps running them if the hub, the laptop, the router and the internet all disappear at once. This is the only part a crop depends on.
The hub
A local service on the grower's own machine holding the history. Their data, their disk, on their side of the router. Nothing is uploaded and there is no account to lose access to.
This site
The agronomy and the arithmetic — recipes to take away, a simulator to size a room, a parts list. Useful before you buy and between crops. If it went offline tomorrow every installed room would carry on exactly as before.
Simulate a room
Run twenty-one days of a crop against a physical model of your room in about a second. It will tell you if your fogger cannot keep up, if your compressor is short-cycling, and how many litres of water and units of electricity the crop costs.
Run a crop →The recipe library
6 species, staged from spawn run to the last flush, with the reasoning for each band. Export any of them as a file and take it to a controller that has never seen the internet.
Read the recipes →Size the hardware
What to buy, what it costs in rupees, and which of it your room actually needs — fan, fogger and cooling sized from your volume and your substrate load rather than from a catalogue.
Size a build →The one thing worth knowing
Relative humidity is the wrong target and almost everyone uses it. What decides whether a mushroom dries out is the vapour pressure deficit at the surface of the cap — the gap between what the air could hold at the cap's temperature and what it is actually holding. The same 88% humidity is a mild 0.25 kPa in an 18 C oyster room and a punishing 0.57 kPa in a 32 C milky room. A hygrometer cannot tell those apart. A cold wall at 90% humidity is already condensing, and that is where bacterial blotch starts.
| Stage | Air | Humidity | Deficit |
|---|---|---|---|
| Grey oyster, pinning | 17.0 °C | 91 % | 0.17 kPa |
| Grey oyster, fruiting | 18.0 °C | 88 % | 0.25 kPa |
| Lion's mane, fruiting | 20.0 °C | 92 % | 0.19 kPa |
| Pink oyster, fruiting | 27.0 °C | 87 % | 0.46 kPa |
| Milky, fruiting | 32.0 °C | 86 % | 0.67 kPa |
Computed with the Tetens equation from the temperature and humidity beside them. Cap temperature is assumed equal to air temperature, because the base build has no infrared sensor — a real fruiting body runs two to three degrees cooler than the air it sits in, so the true deficit at the surface is lower than these figures.
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.