Mushroom Farm Monitor: CO2, Humidity, and Temperature

Mushroom farming requires precise conditions: temperature, humidity, and CO2 within narrow ranges. A Rs 5,000 sensor system prevents crop losses and improves yield consistency 20-30%.

Environmental Requirements

Button mushroom: spawn 22-25C 85-90%RH, fruiting 14-18C 80-85%RH CO2<1000ppm. Oyster: spawn 25-28C 85-90%RH, fruiting 20-25C 85-95%RH CO2<800ppm. Shiitake: spawn 20-25C 60-70%RH, fruiting 12-18C 80-90%RH. Brief excursions cause abnormal growth or crop failure.

Sensor Selection

DHT22 at substrate and ceiling levels for temperature stratification monitoring. BME280 adds pressure data — pressure changes affect air exchange rates in sealed rooms. MQ-135 or MH-Z19B for CO2.

Monitoring and Control System

Environmental controller:

#include <DHT.h>
#include <Adafruit_BME280.h>
DHT dht(2,DHT22); Adafruit_BME280 bme;
float targetT=22, targetH=90; int maxCO2=800;
void loop(){
  float t=dht.readTemperature(), h=dht.readHumidity();
  int co2=map(analogRead(A0),0,1023,400,5000);
  // Heater/cooler for temperature
  // Humidifier for humidity
  // Exhaust fan for CO2
}

CO2 Management

CO2 is the most underappreciated factor. Sealed rooms can reach 5,000+ ppm within hours. Above 1,500ppm: long thin stems, small caps, 40-60% value loss. MQ-135 provides approximate readings; MH-Z19B gives +/-50ppm accuracy.

Humidity Control

Ultrasonic mist makers are most effective for small rooms (<20 sqm). They atomise water into fine fog maintaining high humidity without wetting substrate surface (which promotes contamination).

Automation for Varieties

Switch between species/phase presets stored in EEPROM. For Indian conditions, oyster mushrooms are the most forgiving and profitable entry point with payback in 2-3 cycles (60-90 days).

Frequently Asked Questions

Most important sensor?

Humidity. Even 30min below 80%RH causes pinhead abortion in oyster mushrooms.

Grow without climate room?

Oyster in semi-open bamboo structures Oct-Feb when natural temps are 15-25C. Still need humidity monitoring.

ROI?

200 sqft unit: 80-100kg/month at Rs 150-160/kg = Rs 12-16K/month. Sensor system prevents 20-30% losses.

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