Button mushrooms

Agree where an uncertain load will wait and who can authorise its use. Spawning questionable compost commits further money and makes later cause tracing harder. Keep the supplier's instructions with the batch instead of mixing advice from different compost systems. Use the detailed compost and parameter pages below for the preparation method being used.

Check moisture in the layer itself as well as conditions above it. A room can feel humid while the casing has dried. Conversely, a wet-looking surface can hide compaction or poor distribution. Learn to compare samples under a consistent method with a trained grower; do not turn one photograph or a hand-squeeze description into a universal acceptance test.

Reconcile gross harvest, trimmed or rejected mass, packed quantity, sales and returns. Include room turnaround time when planning the next crop. Filling a room earlier is not an improvement if cleaning, maintenance or compost readiness has been compromised.

Two beds share the same room air but only one develops poorly. Check whether they also share the compost lot, spawn lot, casing batch, filling depth and watering history. Shared air makes a room-wide climate explanation less convincing by itself; it does not exclude a local airflow or bed-temperature problem.

Agaricus bisporus, the white button mushroom, is a fungus. It has no roots or leaves. Its body is a web of fine white threads called mycelium, and what you sell is its fruit body.

In nature it lives on rotted horse manure and straw and cannot digest fresh straw. So the grower first ferments straw and manure into compost the fungus can eat and its competitors cannot. Then the grower adds a moist soil layer, the casing, because casing supports reliable commercial fruiting. Everything else on the farm serves those two facts.

The crop climbs fixed rungs. Phase I ferments raw straw. Phase II pasteurises it and clears ammonia. Spawning mixes in grain coated with mycelium. Spawn run is the 12 to 14 days in which mycelium fills the compost. Casing lays 3 to 4 cm of soil on top. Case run lets mycelium climb into that soil, about a week. Pinning is when the grower changes the room and pinheads appear. Cropping is the weeks of picking, in waves called flushes.

ICAR-DMR gives a duration for each rung but no single day count from spawning to last flush. Learn the ladder, not a total.

The fungus wants warmth to spread and cool to fruit. ICAR-DMR's species table puts spawn run at 22 to 25 °C and fruiting at 14 to 18 °C. Hold the first band until the compost is colonised, then move the room into the second.

The drop is not a small adjustment. With fresh air and lower carbon dioxide it is the signal that tells mycelium to stop spreading and start fruiting. A seasonal grower in the plains gets that drop from winter itself. A controlled farm buys it from a cooling unit. Both are managing the same biology.

New growers treat casing as a second layer of food. It is not. Compost carries the carbon and nitrogen the mycelium eats. Casing carries almost none: it holds water, lets carbon dioxide escape, and its surface is where pins form.

So a farm can have good compost and no crop when the casing is too dry, too wet or diseased. And good casing gives a poor crop when the compost was spawned with ammonia still in it. Yield is counted per 100 kg of compost because compost is the input everything else scales from.

A controlled unit has insulated rooms, an air handling unit that cools and humidifies, and usually a Phase II tunnel. ICAR-DMR's planning model assumes 60 day crops, 6 crops per room per year and an air to bed ratio of 1 to 5.

The price of independence from weather is a machine that must run every hour. A controlled farm is judged on crops completed per room per year and on how evenly its rooms perform. One good crop proves nothing, six in a row prove the system, and the power bill has to be paid by the crop.

MIDH guidelines of 2025 give a cost norm of 30 lakh rupees for a production unit, with 40 percent assistance to private growers as a credit-linked, back-ended subsidy. A low-cost norm of 2 lakh rupees for 200 square feet carries 50 percent.

Read these as two doorways, not as advice. The large norm needs a bank loan and full machinery; the small one fits a seasonal start. Know first how many months your site sits near 14 to 18 °C at night, whether power is reliable, where compost will come from, and who buys within a day's travel.

ICAR-DMR sets nitrogen in the mixed raw materials at 1.5 to 1.75 percent of dry weight and the carbon to nitrogen ratio at 25 to 30 to 1, falling to about 16 to 1 after composting.

Both edges matter. Below 1.5 percent the heap may not pass 55 to 60 °C and moulds such as Stachybotrys move in. Above 1.75 percent, nitrogen leaves as ammonia and the compost is invariably infested by Sepedonium yellow moulds and ink caps. Nitrogen comes from whatever is cheap near you: ICAR-DMR gives wheat straw 0.6 percent, deep-litter chicken manure 3.0, wheat bran 2.0 and cotton seed meal 7.0.

Phase I has three jobs. It wets and mixes the raw materials so every straw touches nitrogen and water. It starts a fermentation in which heat-loving microbes eat the easy sugars. And it turns much of the added nitrogen into ammonia and microbial protein for Phase II to finish.

It is deliberately incomplete. ICAR-DMR describes compost after Phase I as having a heavy ammonia smell, a pH of about 8.2 to 8.5, moisture of 72 to 75 percent and ammonia around 800 to 1000 ppm. That is the expected state before pasteurising.

Dry straw repels water. ICAR-DMR wets it for 24 to 48 hours until it holds about 75 percent moisture, roughly 4000 litres per tonne, mixing in the nitrogen sources so fermentation starts everywhere at once.

Heap size follows climate. In the plains ICAR-DMR builds 100 to 120 cm wide; in the cooler hills 130 to 150 cm wide and about 150 cm high. A bigger heap holds heat and a small one never ferments, so never attempt less than 300 kg. Within two to three days the core should reach 65 to 70 °C.

A heap heats from inside. The outer layer stays cool and the core can go anaerobic. Turning moves the outside to the inside and lets air back in.

For the long method ICAR-DMR turns on day 6, day 10, day 13 with gypsum, then days 16, 19, 22 and 25, and fills on day 28: 7 to 8 turnings over 28 to 30 days. The short method runs outdoor Phase I for only 10 to 12 days before a tunnel, and the bunker method finishes in 6 to 8 days with forced air.

Buy a long-stem compost thermometer before anything else. ICAR-DMR says the heap may reach 70 °C in 24 to 48 hours, and that above 80 °C in the core is undesirable because the heap goes anaerobic. A peak stuck near 55 °C says nitrogen is short.

Measure centre, mid-depth and near-surface each morning. One centre reading hides a cold shoulder, and cold shoulders are where competitor moulds start. A sour, black, greasy heap went anaerobic. Insects breed at the last turnings, and current label approval must be checked before using anything against them.

Phase II is called pasteurisation, but that is only its middle act. First comes pre-pasteurisation conditioning: the compost is levelled to a uniform 45 to 48 °C and held in the 45 to 52 °C band for two days. Then pasteurisation, a short controlled peak that kills insects, nematodes and competitor spores. Then post-pasteurisation conditioning, back to 45 to 48 °C until the ammonia is gone.

Run the tunnel as one long hot period instead and you get compost that is clean but still full of ammonia, and the spawn dies in it.

ICAR-DMR finds compost properly pasteurised when it is held at 58 to 59 °C for 4 to 6 hours. It is not pushed there suddenly: the temperature climbs at about 1 °C per hour, reaching the target in 10 to 12 hours largely from the compost's own heat.

The ceiling is hard. Above 60 °C, ICAR-DMR says, all organisms are killed including the thermophilic fungi Phase II depends on, and the same manual names that as a cause of olive green mould. A tunnel needs a compost probe, not an air thermometer by the door.

After the peak the compost is brought down at about 1.5 °C per hour and held at 45 to 48 °C. Surviving heat-loving fungi turn free ammonia into their own bodies, which the mushroom later eats. This step is what makes the compost selective. ICAR-DMR says it takes 3 to 4 days in a modern tunnel, or until the compost is free of ammonia.

Two limits protect it. Never condition below 40 °C, because mesophilic fungi set in and spoil the compost. Keep oxygen above 10 percent, since the fan is not optional.

A tunnel is filled 2 to 2.2 metres deep at about 900 to 1000 kg per square metre, with air pushed up from the plenum below. ICAR-DMR insists that the air above the compost, the compost itself and the plenum differ by no more than 3 °C, or one layer is under-pasteurised while another is over-cooked. On a small farm, probe a covered heap top, middle and bottom.

Finished compost has ammonia below 10 ppm, moisture around 64 to 66 percent with no liquid oozing when squeezed firmly, and a dark crumbly texture.

Spawn is sterilised grain that a laboratory has grown mushroom mycelium through. It is not seed. Nothing crosses or pollinates on your farm, so every mushroom in the bag is a copy of the strain the lab supplied.

Strain choice therefore travels with the spawn. The NHB model report lists Indian strains from 14 to 16 kg per 100 kg compost up to 22 to 27 kg for DMR-NBS-5, measured with spawn run near 24 °C and fruiting near 15 °C. Buy from a recognised laboratory and note the strain and lot number.

Spawning should follow a documented release decision. Confirm that conditioning and cooling are complete under the selected production protocol. Use suitable calibrated instruments and representative sampling; record temperature, moisture and validated ammonia results against that protocol.

Do not infer an ammonia concentration from smell or deliberately inhale compost gases. A lack of smell does not prove safe working conditions or crop readiness. If a criterion is unresolved, hold the batch and obtain a competent assessment before adding spawn.

ICAR-DMR mixes grain spawn at 0.5 to 0.7 percent of the wet compost weight. Its Hindi farmer folder gives 0.5 to 0.75 percent, which is 500 to 750 g for 100 kg of prepared compost. More spawn is not better: it costs more and adds heat.

Mix so grains are spread through the whole mass and not left in a band. The manual fills polythene bags 12 to 15 inches deep, or shelf beds 6 to 8 inches. The folder says 10 to 12 kg per bag, because a deeper bag overheats in the middle.

Each grain of spawn is a starting point. Mycelium grows out of it in every direction, digests the compost and joins threads from other grains. The compost changes from dark brown to light brown as the white web spreads, and ICAR-DMR treats that colour change as the sign the run is complete.

The fungus also makes heat. ICAR-DMR holds the room at 23 plus or minus 1 °C, which gives a bed temperature of 24 to 25 °C, one to two degrees higher. The number that matters is therefore the compost temperature, not the air.

Spawn run wants warm, still, wet and stale air. ICAR-DMR recirculates all of the air with no fresh-air entry, keeps carbon dioxide between 10000 and 15000 ppm, and works at 95 percent relative humidity in a controlled room. Its seasonal folder gives 22 to 25 °C and 80 to 90 percent humidity, because a naturally ventilated room cannot hold 95 percent.

Carbon dioxide is useful here. It helps the mycelium move through the compost. After casing the same gas becomes the thing you must remove, so the fan settings for the two stages are opposite.

Warm helps, hot does not. The NHB model report, reproducing ICAR-DMR guidance, says temperature above 26 to 27 °C during spawn run and after casing should be avoided. ICAR-DMR adds that false truffle, a competitor that ruins compost, appears above 23 °C and is common in February and early March in the north Indian plains.

The run takes 12 to 14 days under controlled conditions, and the Hindi folder gives 12 to 15 days for a seasonal room. Do not case on a date. Case when the compost has turned light brown right through.

Observe bags without unnecessary opening or handling. Use the farm's hygienic measurement procedure at representative locations and record the same points at comparable times. Compare development across bags, material lots and room positions.

Record stalled growth, abnormal colour, visible insects and packaging damage. Do not deliberately smell bags or diagnose their cause from odour. Several input, environmental and biological problems can produce similar signs; preserve the batch record and obtain an assessment before treating the crop.

The mushroom will not fruit on bare compost. ICAR-DMR calls casing a 3 to 4 cm layer of soil laid on spawn-run compost and a prerequisite for fruiting.

It works in four ways. It holds a reserve of water the crop can draw on. It lets carbon dioxide escape from the compost below. It supports the crop physically. And its bacteria give the signal that turns spreading mycelium into pinheads. What it does not do is feed the crop. Casing carries almost no nutrition, and a rich casing grows moulds rather than mushrooms.

Peat is the world standard and is not available here, so ICAR-DMR lists substitutes: well decomposed farmyard manure, preferably two years old; two-year-old spent mushroom compost; composted coir pith; and mixtures of these in stated proportions. In Haryana and Punjab burnt rice husk is used along with decomposed farmyard manure. The farmer folder's seasonal mix is two-year-old farmyard manure and loam soil in equal parts.

Quality is specified rather than assumed. ICAR-DMR asks for a neutral pH of 7.0 to 7.5 and low electrical conductivity, in the range of 400 to 600 micromho.

Casing is the main route by which wet bubble enters a farm. ICAR-DMR reports that its resting spores survive up to three years in casing soil, so soil carried over from an old crop is a standing risk.

Wet the material to 50 to 60 percent of its water holding capacity first, because dry soil does not carry heat. ICAR-DMR then steam pasteurises at 60 to 65 °C for 6 to 8 hours. Its wet bubble folder gives a shorter, hotter schedule of 54.4 °C for 15 minutes. Chemical drenching is also documented, and current label approval must be checked.

The 2011 manual gives two thicknesses. It defines casing as a 3 to 4 cm layer, then instructs an even 4 to 5 cm applied using 4 cm iron rings or wooden blocks. The Hindi farmer folder says 3 to 4 cm. Pick one figure, write it down and keep it the same on every bed.

Evenness matters more than the number itself. A thin patch dries first and pins early, a thick patch pins late, and the bed then carries two flushes at once. Do not press the layer down, and water it lightly rather than flooding it.

Case run is the week in which mycelium leaves the compost and grows up into the casing. ICAR-DMR runs it at 24 plus or minus 1 °C with 95 percent relative humidity and carbon dioxide above 7500 ppm, with no fresh air, for about one week. The settings are close to spawn run, deliberately.

Its end point is visible. ICAR-DMR looks for mycelium in the casing valleys, the low lines between the ruffled high spots. When white threads show there across the whole bed, the layer is ready for the change.

This is the last week in which you can water heavily. Once pinheads appear, water sitting on them marks and spoils them, so the casing must carry its reserve before that. ICAR-DMR wants about 50 plus or minus 2 percent moisture in the casing at pinning.

Water little and often rather than once and heavily. Water that runs through into the compost does not come back and drives out air the mycelium needs. Judge by lifting a pinch from three places: it should be damp all through, not wet on top and dusty underneath.

An uneven case run is information, not a nuisance. Gather the context before changing anything.

Note days since casing, because a bed on day 4 and a bed on day 8 are not the same problem. Measure casing depth at five points, since a thick patch simply takes longer. Read compost temperature as well as air, because the bed still runs above the room. Note where the slow area sits: near the door, under a vent, at one end of a rack. The same symptom from a different cause needs a different answer.

When mycelium shows in the valleys the room changes: temperature down towards the fruiting band, fresh air in, carbon dioxide down. ICAR-DMR reports pinheads 3 to 4 days after that change.

Timing is the risk. Change too early and the mycelium has not reached the surface, so pinning is thin and late. Change too late and it overgrows the casing into a dense mat that pins poorly. NHB, following ICAR-DMR, adds that temperature above 26 to 27 °C after casing must be avoided, so a warm week is a problem to fix.

Mushrooms form where water is leaving the casing surface, so moving air matters as much as the thermometer.

DMR measures 31 g of water leaving one square metre of bed every hour at 17 C and 85 per cent humidity, and puts the permissible air speed over the bed at 15 cm per second. A dead corner with no air movement will not pin, even though the wall thermometer looks right. Air that is too fast and too dry crusts the casing and kills young pins.

Casing moisture at pinning is 48 to 52 per cent, judged by squeezing the casing itself.

The crop is your second meter. DMR states that high carbon dioxide at pinning can seal the casing surface or give onion shaped mushrooms with a bulbous base and a small cap. Between pinhead and button stage, high carbon dioxide gives long stalks with small open caps.

Once pins have become buttons the cropping band is 1000 to 1500 ppm. If your pins look like onions or your stalks run long, you are venting too little, whatever the meter says.

With no meter, read the crop and write down what you see each day.

DMR publishes three schedules and they give different crops. Soft airing brings air to 19 C in 48 hours and 17 C in 72 hours, with carbon dioxide falling from 4000 to 1000 ppm over those 72 hours, and gives smaller, better spaced flushes. Severe airing takes air to 15 C as soon as possible and carbon dioxide below 1000 ppm in 12 hours, for a heavy first flush. Moderate airing sits between them.

Pick by your labour and your buyer, not by habit. Four DMR documents give four fruiting bands between 14 and 18 C, so do not chase one number.

After venting, pinheads appear in 3 to 4 days and reach picking size in another 3 to 4 days. The bed then goes quiet while the mycelium rebuilds, and a second wave follows.

DMR's Hindi farmer folder gives 8 to 10 weeks of picking in seasonal cultivation. Environment controlled units plan a 60 day room cycle and 6 crops per room per year.

DMR does not publish a line saying first flush on day N with so many flushes in total, because compost, strain and room all move it. Your own diary is the calendar.

Carbon dioxide production peaks in the first two flushes, when DMR measures about 10 g of carbon dioxide per square metre of bed per hour.

For that period DMR asks for about 6 air changes per hour, with the fresh air vent at 30 per cent and 70 per cent recirculated. From the third flush, 4 air changes per hour hold oxygen near 16 per cent and fresh air drops to 20 per cent. Room carbon dioxide during cropping sits at 1000 to 1500 ppm.

Running full fresh air all crop long only burns power and dries the casing.

Pick the bed truly clean. Every stump, broken stalk and dead pin left behind is food for moulds and a breeding site for flies.

Put back the water the crop took away. DMR's rule is one litre of water for every kilogram of mushroom harvested, applied after picking rather than onto swelling pins.

Hold the band steady. Warming the room does not restart a crop, it only invites disease. Expect each flush to be smaller than the one before and plan labour that way, so your pickers are not idle in week six.

DMR's Table 7.1 gives yields per 100 kg of compost by method: long method 10 to 15 kg, short method 18 to 25 kg, indoor method 20 to 30 kg. Some seasonal growers taking a single crop have reported 18 to 22 kg with long method compost.

NHB's strain table runs from 14 to 16 kg for older strains to 22 to 27 kg for DMR-NBS-5 under Indian conditions. DMR's own project model assumes 18 kg per 100 kg compost.

These are reported ranges, not promises. Weigh your compost and weigh your crop.

There is the temperature the fungus wants, the temperature your probe reads, the temperature in the far corner, and the temperature the machine can hold.

DMR makes the first gap plain: during spawn run the air is held at 23 plus or minus 1 C, which gives a bed temperature of 24 to 25 C, because compost makes its own heat and runs 1 to 2 C above air.

The bed keeps making heat in cropping too. A room that reads correct at the door can still be too warm inside the bed.

Air speed at the bed is limited to 15 cm per second, and may be raised only if the air is humidified. Fast dry air is a drying machine pointed at your casing.

DMR's crop chapter gives 85 per cent humidity for pinning and cropping, and the watering section gives an operating band of 80 to 85 per cent. Spawn run and case run are given as 95 per cent in controlled rooms.

The Hindi farmer folder gives 80 to 90 per cent for the same seasonal stage, because a naturally ventilated bamboo or brick room cannot hold 95 per cent. Both are DMR, and each is honest about the room it describes.

NHB warns that humidity above 85 per cent with temperature above 20 C is the condition bacterial blotch likes.

If you have no cooling, your calendar is your cooling. DMR gives white button months as October to February in the plains in the manual and November to February in the seasonal folder, September to March in the mid hills and March to November in the high hills.

Before buying machinery, size it against the loads DMR publishes: heat from the bed, carbon dioxide from the bed, and 31 g of water leaving each square metre every hour. A unit that cannot remove that water cannot hold your humidity band.

The casing layer is a water store. The mycelium sits inside it, draws water up into the growing mushrooms, and the surface loses water to the air all day long.

So watering is refilling a store, not washing a crop. Humidity in the air and water in the casing are two different things.

Judge the casing by hand. DMR gives casing moisture at pinning as 48 to 52 per cent, and the field method is to squeeze a pinch of it and see whether it holds together without water running out.

DMR's rule is to spray at the rate at which the mushrooms were harvested: for every kilogram picked, add one litre of water.

Give it in light passes rather than one drench. A heavy single watering runs through the casing, reaches the compost, and pushes out the air the mycelium needs. Time the water after picking, not onto swelling pins, because young pins that are watered directly stop, discolour and are lost.

Between flushes, when the bed looks empty, the casing store still has to be refilled, so keep watering lightly on those days.

DMR reports that bacterial blotch spots spread when temperature is at least 20 C and a film of free water sits on the cap, and that a film lasting more than about three hours is the dangerous case. NHB adds that humidity above 85 per cent with temperature above 20 C should be avoided.

That gives a practical rule needing no chemical: after watering, run air movement until caps are dry to the touch. Never leave a wet crop overnight in a warm room.

If blotch appears, treat it as a climate and water problem first.

Over wet casing brings cinnamon mould, which DMR lists against casing that is too wet or too strongly disinfected. Over wet compost is worse: above 72 per cent moisture at spawning the compost goes airless and plaster moulds appear.

The opposite fault shows up as weepers. NHB describes leaking, stinking mushrooms where the compost is below 64 per cent moisture and the casing above it is wet.

Dry casing cracks and crusts, pins abort at the tray edges first, and the mushrooms that do come are small and open early.

Four questions come before any name. Is it one tray or the whole room. Is it near the door, under a duct, or spread evenly. Which flush is running. What changed on the farm about three days earlier.

Negative evidence counts too: if the same compost in the next room is clean, the compost is probably not the cause.

Write these four answers in the diary before you telephone anyone. A KVK scientist or the ICAR-DMR helpdesk can work with that description. Nobody can work with the words the crop is finished.

DMR's table of causes reads like a compost audit. Green mould follows low compost pH, carbohydrate rich and nitrogen poor compost, or immature spawn. Ink caps follow free ammonia, too much nitrogen or old straw. White plaster mould invades when compost pH sits outside 7.2 to 7.8. Olive green mould follows poor aeration in Phase II or pasteurisation above 60 C.

Cinnamon mould follows casing that is too wet or too strongly disinfected.

So the honest question after a mould outbreak is not which spray, it is which step in the last three weeks was out of range.

Some problems give you days, not weeks. DMR states that dry bubble, if left uncontrolled, can destroy a crop in 2 to 3 weeks.

Wet bubble is carried by the casing soil, and DMR's folder records that its resting spores survive there for three years, which is why casing source and treatment matter more than any later action.

False truffle appears above 23 C, which in the north Indian plains means February and early March. Bacterial blotch needs 20 C and free water on the cap. Each of these is a measurement you can take today.

Sciarid flies are managed by counting, not by smell. DMR's threshold table treats any live adult in the first flush as an action point, and more than 20 catches per trap per week from the second flush onwards.

NHB describes 35 mesh nylon screening on doors and ventilators, and a 15 W yellow light trap over an oil coated sheet.

This site prints no pesticide names or doses. Approvals change and mushrooms are eaten fresh. Check the current label approval for mushrooms in India and your state advisory, and note the exact approved product label and required pre-harvest interval; no universal 48-hour rule is appropriate.

Walk the bed twice a day in the flush and pick to the size your buyer pays for, not to the biggest size you can grow.

Hold the cap, twist gently and lift, so the stalk comes away without pulling the casing with it. Fill the hole left behind with a little casing.

Trim the soil stained base with a clean knife at the bed, so soil never travels with the crop. Place mushrooms gills down in shallow crates and never heap them deep, because the weight bruises the caps underneath.

Pick the bed clean, including small dead pins, and remove every stump. Leftovers feed moulds and flies into the next flush. Then put back one litre of water for each kilogram picked.

DMR records that Indian local markets use retail packs of 200 g or 400 g, so a farm that grades at the bed can fill those packs straight from the crate. Your buyer's specification is the final word, so write it down and train pickers to it.

The moment a mushroom leaves the bed it is still breathing and still warming. ICAR-DMR's post harvest bulletin puts field heat at picking at 15 to 18 C and asks that the mushroom's own temperature be brought to 4 to 5 C as fast as possible.

The manual's practical instruction is to grade, pack and chill at 4 C for 6 to 8 hours before sending to market.

So the harvest job does not end at the crate. On farms without a cold room, pick earlier in the morning and move faster to the buyer.

A picked mushroom keeps breathing, and breathing burns the crop's own weight and quality. ICAR-DMR's post harvest bulletin estimates that mushrooms at 10 C respire about 3.5 times faster than at 0 C.

So the first job is not the box, it is the temperature. The bulletin asks that mushroom temperature be brought down to 4 to 5 C as quickly as possible, from a field heat of 15 to 18 C at picking.

A farm with no cold room can still pick into shade, keep crates shallow, and reach the buyer while the crop is cool.

The chain is short and each step has a published band. Pre cool first, then hold. DMR's manual grades, packs and chills at 4 C for 6 to 8 hours before despatch.

Ordinary refrigerators run at 4 to 7 C, chill storage may go to minus 1 to minus 4 C depending on how fresh the crop is, and freezing is done below minus 18 C.

What matters is that the crop never warms again. A crate chilled to 4 C and then left on a hot platform for an hour has lost the benefit.

DMR records that Indian local markets use retail packs of 200 g or 400 g in thin polythene. For longer holding, the manual gives an optimum storage atmosphere of 2.5 to 5 per cent carbon dioxide with 5 to 10 per cent oxygen, and says that in pack humidity of 87 to 90 per cent gives the best colour.

Over wrapped punnets can hold a fresh appearance for about three days at 18 C.

Start simple: shallow crates, a clean liner, no heaping, and a pack size your buyer actually sells.

So measure your own losses by route and by season and write them down. Your own record is the only shelf life figure that applies to your crop.

Spent compost, waste crates and old casing belong far from the doors. Clothes worn in the last room of the day should not be worn into the first room next morning.

So a hygiene routine has a number in it. Count traps weekly, write the count on the room board, and act on the trend.

The last day of a crop is the most powerful disease control day you have. NHB records a cook out of the spent compost at 70 C held for 12 hours to kill pathogen mycelium and spores, and 70 C for 2 to 3 hours for insect pests.

Spent compost and used casing then go well away from the rooms, into a pit covered with at least 10 cm of manure, which stops flies breeding in it.

Wet bubble spores survive three years in casing soil, so used casing is never reused and never stored near a door.

Check the current label approval for mushrooms in India and your state advisory before any chemical decision, and note the exact approved product label and required pre-harvest interval; no universal 48-hour rule is appropriate.

Then the arithmetic is simple. Compost weight divided by 100, multiplied by a yield figure from the published range, gives a production estimate. From that, subtract what you will not sell: mushrooms that open, bruise or are rejected. What is left is saleable yield, and only saleable yield earns anything.

Use the range for the compost you actually make, and the lower end for a first crop. None of these ranges is a promise to you.

The only Indian cost of production figure in our source set comes from DMR's undated Hindi farmer folder, which reads as early 2010s. It gives a seasonal white button production cost of Rs 20 to 25 per kg and states a margin of at least Rs 25 to 35 per kg.

That is a reference from another decade, not a forecast for you. Straw, spawn, coal, labour and power have all moved since.

Price your own inputs this week and keep the DMR figure beside yours only as a sanity check.

It is credit linked and back ended, a bank loan is mandatory, and it covers capital cost only.