MushroomFarming / technical parameter

Button Mushroom climate system

Understand temperature, humidity, carbon dioxide, airflow, evaporation and condensation as one interacting system.

Practical explanation + detailed referenceSources & review ↓

Real cultivation photograph. Read its source for location and context; it is not a universal operating specification.Andrew Bossi · CC BY-SA 2.5View full photograph ↗

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Read this in the full guide: Run a Button mushroom crop from receipt to room reset →

Understand the topic

What you need to know.

A button room has four readings that move together: temperature, humidity, carbon dioxide and air movement. Change one and the others follow. This page explains how they link, gives the ICAR-DMR targets for each crop stage in controlled and seasonal rooms, shows why the machine must run colder and wetter than the crop, and lists what the mushrooms show when the climate is wrong.

Teaching revised 2026-09-24. Source-linked editorial synthesis; this date does not imply independent technical review.

Part 01

Temperature, humidity and carbon dioxide move together

The ICAR-DMR manual treats the three as one system. When temperature rises, humidity falls, and the reverse. Temperature also changes how much carbon dioxide the compost gives off. The manual says all three work in synergy to bring on pinning, and pinning suffers if any one of them is out of range.

Every room also has two temperatures: the air and the bed. The compost and mycelium make heat, so the bed normally runs 1 to 2 °C warmer than the air around it. The manual reads both with two ordinary stem thermometers, one pushed into the bed and one hanging in the air a few centimetres away.

That pair of thermometers doubles as a humidity check. If the bed reads cooler than the air, water is evaporating from the bed too fast, which means the room is too dry. The manual calls this a situation to be avoided at any cost.

Source: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption

Reading the pair of thermometers

BedOne stem thermometer pushed into the bed.
AirA second one hanging in the air a few centimetres away.
CompareIn a healthy room the bed reads 1 to 2 °C above the air.
ActBed cooler than air: the room is too dry, so raise humidity.

Part 02

Targets for each stage, in controlled and seasonal rooms

The manual gives these values for rooms with an air handling unit. Its crop chapter and its climate section print slightly different case-run figures; both are shown. The ICAR-DMR Hindi folder gives its own cropping band for seasonal rooms without cooling.

Spawn run, air23 plus or minus 1 °CBed 24 to 25 °C, humidity 95 percent, fresh air closed so carbon dioxide builds to 10,000 to 15,000 ppm.

Case run, air23 plus or minus 1 °CClimate section: same as spawn run for about 7 days. The crop chapter gives 24 plus or minus 1 °C, 95 percent humidity and carbon dioxide above 7500 ppm.

Pinning, air15 to 17 °CThe room gets there within 2 to 3 days of case run ending. Humidity lowered from 95 to 85 percent, carbon dioxide to 800 to 1000 ppm with the fresh air vent at 30 percent.

Cropping, carbon dioxide1000 to 1500 ppmOnce pinheads become buttons, fresh air can be slightly reduced to this level.

Temperatures to avoidabove 26 to 27 °CDuring spawn run and after casing; keep cropping below 18 °C. NHB's model DPR repeats both.

Seasonal room, cropping16 to 18 °CTemperature held for the whole cropping period, with humidity about 85 percent (ICAR-DMR Hindi folder).

Sources: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption · ICAR-DMR button folder · NHB DPR model, 2018

Part 03

Why the machine runs colder and wetter than the crop

The manual works through one example. To hold 17 °C and 85 percent humidity at the bed, air leaves the air handling unit at 14 °C and 100 percent humidity. Crossing the beds, it picks up heat from the crop, warms to 17 °C, and its humidity falls to 85 percent on its own.

So the set point on the machine is not the crop target. A unit set to the crop figure leaves the beds too warm and too dry.

The loads the air must carry are published too. At 17 °C and 85 percent humidity, 31 g of water evaporates from each square metre of bed every hour. In the first two flushes each square metre of bed also gives off about 10 g of carbon dioxide an hour, and about 10 W of heat, a figure the manual gives at 17 °C and 88 percent humidity. The air has to take away all three. A unit sized only for cooling can still fail to hold humidity or carbon dioxide.

Source: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption

The path of the air in the manual's example

Leaves the unit14 °C and 100 percent humidity.
Crosses the bedsPicks up heat from the crop and warms.
At the bed17 °C and 85 percent humidity, the crop target.
ReturnsCarrying water, carbon dioxide and heat back to the unit.

Part 04

Check that the air reaches the middle of the room

Air changes describe how much air moves, not where it goes. For most of the crop the manual sets the fresh air valve at 20 to 30 percent and recirculates the rest. It also sets a speed at the crop and gives a simple way to check that the air arrives.

Know the targetAir speed over the crop beds should be about 15 cm per second. The manual wants gentle movement that carries carbon dioxide and heat away from the crop canopy.
Test the hardest spotGo to the central shelf in the middle row, which the manual names as the place to make sure air is moving.
Use smokeHold a burning incense stick there and watch which way the smoke drifts. No drift means no air movement at the crop.
Compare the endsRepeat near the air inlet and at the far end, and read the bed and air thermometers at each place.
Filter the fresh airThe manual fits 2 µm mesh filters where fresh air enters, to keep out spores of disease and competitor moulds.

Source: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption

Controlled room: how the air moves

Cooled, humid air drops from the overhead duct onto the beds, returns through the room, and 20 to 30 percent fresh air is mixed in. About 15 cm per second over the beds, 4 to 6 air changes an hour. Source: ICAR-DMR manual.

Supply airReturn airBeds

Part 05

What the mushrooms show when the climate is wrong

The crop records the climate it grew in. These are the manual's links between a sign and a climate cause. Some of the same signs also have disease causes, so confirm them with readings.

Onion-shaped mushrooms with a bulbous base and a small cap at pinning: carbon dioxide too high. Dry bubble can also produce onion shapes.
Long stems with small, opened caps as the crop develops: carbon dioxide trapped around the crop by poor air movement. Long stems can also indicate virus disease.
Pinning stops and the casing seals over: temperature held too high for too long during cropping, or humidity falling below 85 percent.
Scales or cracked skin on the cap top: fast air combined with low humidity.
Mass pinning, or pins forming below the casing: a sudden fall in temperature, too much aeration, or carbon dioxide lowered earlier than recommended.
Water condensing on caps after temperature swings at high humidity: the manual says this must be avoided, because it favours bacterial blotch.

Source: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption

Part 06

Without cooling, the calendar is your climate control

The manual's seasonal rooms have no insulation and generally use no energy for heating or cooling. The crop stages are timed to match the outside temperature. Its round-the-year chapter gives the white button windows.

IfYou grow in the plains of north India: ThenPlan white button for the winter months, October to February.
IfYou grow on medium elevated land: ThenThe manual's window is September to March.
IfYou grow at high elevation: ThenThe manual says high elevated land suits white button for most of the year.
IfYour seasonal room cannot hold the controlled-room figures: ThenWork to the Hindi folder's band of 16 to 18 °C and about 85 percent humidity in cropping, open doors and windows for a while morning and evening, and record the readings you actually reach.

Sources: ICAR-Directorate of Mushroom Research: Mushroom Cultivation, Marketing and Consumption · ICAR-DMR button folder

A worker with harvest crates walks between tiered bamboo bed racks inside a low-cost button-mushroom grow house near Mount Bromo, East Java, Indonesia. — Inside a low-cost bamboo button mushroom grow house in Indonesia, with tiered beds and a worker. Rooms like this follow the season, not a machine. Photo: Ekaterina Kvelidze, CC BY-SA 4.0. Source

Keep exploring

Every part of this topic.

Choose the stage, material or decision you need to understand next.

Temperature in Button Mushroom rooms

Read air, compost, surface and product temperature as different measurements with different decisions.

Humidity in Button Mushroom rooms

Use relative humidity with temperature, crop-surface condition and sensor context.

Carbon dioxide in Button Mushroom cultivation

Interpret carbon dioxide as a crop and ventilation signal across stage, location and room load.

Airflow in Button Mushroom rooms

Separate fresh air, recirculation, distribution and crop-zone velocity when diagnosing a room.

Evaporation and the crop surface

Use crop, casing, air and water observations to reason about moisture movement.

Condensation risk in growing rooms

Understand why surfaces become wet and how envelope, climate and operations contribute.

Go deeper

Technical reference, records and tools.

Detailed crop-stage information, parameters, diagrams and specialist tools are kept together below. This material retains its source conditions and review limits.

Open the complete technical reference

Button Mushroom · technical parameter

Button Mushroom climate system

Agaricus bisporus

Understand temperature, humidity, carbon dioxide, airflow, evaporation and condensation as one interacting system.

Publication: Public editorial page
External review: Not yet recorded · needed from Button Mushroom technical reviewer
Updated: 2026-08-22
Evidence records: 2

White button mushrooms on casing soil in long shelf beds inside a commercial cropping room near Eger, Hungary. — Button mushrooms on casing in long shelf beds inside a grow room (Hungary). Photo: Andrew Bossi, CC BY-SA 2.5. Source

Room climate by crop stage

Button mushroom, room air temperature. Case run spans 23 ± 1 °C (climate section) and 24 ± 1 °C (casing section). Source: ICAR-DMR manual 2011.

Temperature bandRelative humidity

Quick orientation

A growing-room display is a partial model of what the crop experiences. Useful climate control joins calibrated measurements, crop observations, equipment state and spatial distribution.

System role

The climate hub connects six parameter guides to the crop stages where they matter.

What to observe

Build a record before making a change.

Air and compost temperatures
Air moisture state
Carbon dioxide distribution
Crop-zone movement, evaporation and surfaces

Decision framework

Use the observation to narrow a decision, then verify the response.

Define where a value is measured
Control interactions rather than isolated setpoints
Map rack-zone differences
Verify the response after every change

Dependencies and handoffs

This topic cannot be interpreted in isolation.

Crop stage
Room load
Envelope
Air-handling system
Sensor calibration

Practical layer

Start in the room with air and compost temperatures and air moisture state. Record location, stage and recent events before changing the process.

Technical layer

The technical model joins crop stage, room load, envelope. Any operating value must be attached to a registered parameter, measurement location and applicable condition.

Evidence boundary

This page is grounded in: Farm Design for White Button Mushroom Cultivation; Mushroom Cultivation, Marketing and Consumption. Source provenance does not remove the need to check stage, system, date and local applicability.

Progressive depth

Go deeper without losing the field question.

PracticalWhat to notice in the room

Air and compost temperatures
Air moisture state
Carbon dioxide distribution
Crop-zone movement, evaporation and surfaces

TechnicalHow the interacting system is interpreted

Crop stage
Room load
Envelope
Air-handling system
Sensor calibration

ResearchWhich evidence records govern this page

ICAR-DMR-FARM-DESIGN
ICAR-DMR-CULTIVATION-MANUAL

Technical registry

The numbers for this stage, with their source.

Values are published from ICAR-DMR guidance with the stage and measuring point they apply to. A parameter still marked pending has no published Indian value yet.

BUTTON.CLIMATE.AIR_TEMPERATURE

Room air temperature

14 to 25 °C

Spawn run 22 to 24 °C, case run 23 to 25 °C, fruiting 15 to 17 °C in controlled rooms; the seasonal tables give 14 to 18 °C for fruiting.

Stage: Crop-wide
Measured at: Defined crop-zone position
Crop meaning: The control variable that interacts with compost temperature, evaporation and crop stage.
Applicable conditions: Stage; Strain; Sensor location; Room system

published sourced

BUTTON.CLIMATE.COMPOST_TEMPERATURE

Compost temperature

20 to 25 °C

24 to 25 °C during spawn run, easing to about 20 °C once the room is aired for pinning.

Stage: Colonisation and cropping
Measured at: Within compost at defined bed positions
Crop meaning: Crop heat, which can sit above room-air readings.
Applicable conditions: Stage; Crop load; Probe placement

published sourced

BUTTON.CLIMATE.RELATIVE_HUMIDITY

Relative humidity

80 to 95 % RH

About 95 percent during spawn run and case run, 80 to 85 percent during cropping.

Stage: Crop-wide
Measured at: Defined crop-zone position
Crop meaning: Air moisture state; it does not equal crop-surface wetness.
Applicable conditions: Air temperature; Sensor accuracy; Crop stage

published sourced

BUTTON.CLIMATE.CO2

Carbon dioxide concentration

800 to 15,000 ppm

10,000 to 15,000 ppm during spawn run with no fresh air; 800 to 1,000 ppm for pinning; 1,000 to 1,500 ppm during cropping with 20 to 30 percent fresh air.

Stage: Spawn run through cropping
Measured at: Representative room and rack positions
Crop meaning: A crop-activity and ventilation signal that needs stage context.
Applicable conditions: Stage; Crop load; Fresh-air strategy

published sourced

BUTTON.CLIMATE.AIR_VELOCITY

Crop-zone air velocity

0.15 m/s

ICAR-DMR specifies about 15 cm per second over the beds, with 6 air changes per hour in the first two flushes and 4 later.

Stage: Pinning and cropping
Measured at: Crop level at mapped rack positions
Crop meaning: Local evaporation and distribution over the beds, not ventilation quantity.
Applicable conditions: Rack geometry; Crop density; Instrument

published sourced

BUTTON.CLIMATE.DEW_POINT_MARGIN

Condensation risk margin

Technical value pending verification

Stage: Crop-wide
Measured at: Derived from calibrated air and surface measurements
Crop meaning: Connects surface temperature with air moisture state to explain condensation risk.
Applicable conditions: Surface identity; sensor uncertainty; transient door or defrost events

verification pending

Evidence and review record2 mapped sources

Sources support the page architecture and conceptual guidance. Technical values remain governed separately in the Button registry.

Tier A · foundational

Farm Design for White Button Mushroom Cultivation

Room planning, workflow, environmental-control architecture and engineering vocabulary.

Accessed: 2026-08-22
Publisher: ICAR mushroom research institute

Open original source

Tier A · foundational

Mushroom Cultivation, Marketing and Consumption

Broad cultivation, post-harvest and market context. Values are not promoted without page-level review.

Accessed: 2026-08-22
Publisher: ICAR-Directorate of Mushroom Research

Open original source

Read the evidence

Sources & review.

Editorial update: 2026-08-22. Independent technical review is not recorded for this entry.

Farm Design for White Button Mushroom Cultivation ↗
ICAR mushroom research institute · Foundational official bulletin. Engineering guidance must still be checked against current codes, equipment and project conditions.
Mushroom Cultivation, Marketing and Consumption ↗
ICAR-Directorate of Mushroom Research

Reading a source is not the same as applying its instructions to every farm. Confirm species, strain, crop stage, system, region and publication date. Old chemical recommendations are not current-use instructions.

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