Mushroom Fruiting Room Planner

What a block earns, how many flushes to run, how many blocks the room can carry, and the cash you need first.

Enter your block cost, yields per flush, price and contamination. The page works out profit per block and per fruiting-room slot-week, the best number of flushes, the most blocks you can start a week, the lowest cash point before sales begin, and the contamination rate and price that break even.

Your numbers are used in this browser tab and never leave your device. It does arithmetic on what you enter; it does not tell you how to grow, sterilise or sell mushrooms.

1. Blocks and growing

Cost per inoculated block ($)

Handling minutes per block

Incubation weeks (0 if you buy fruiting-ready blocks)

Blocks lost to contamination (%)

Fresh lb per block, flush by flush

Weeks in the room to first harvest

Weeks between flushes

Turnaround weeks to clear and refill a slot

2. Selling, room and costs

Price per lb ($)

Share of harvest you sell (%)

Packaging and delivery per lb ($)

Harvest and pack minutes per lb

Value of an hour of labor ($)

Fruiting-room slots (blocks at once)

Blocks you start per week

Weekly fixed cost: rent, power, water, loans ($)

Weeks to simulate

Change any number, then click Plan the room.

Result

Profit per block by number of flushes

Flushes	Fresh lb	Profit per block started	Slot-weeks	Profit per slot-week	Added by last flush

Weekly profit at your starts: contamination against price

Week by week

Week	Slots used	Harvest lb	Income	Spend	Cash

How it works, and what it leaves out

Per block: a started block survives incubation with the share you keep after contamination. Each survivor yields the flush weights you enter, sold at price less packaging, minus harvest labor. The block cost and handling are paid for every block started, survivors or not.
Slots: a surviving block holds a fruiting slot for the weeks to first harvest, plus the gap for each later flush, plus turnaround. Starts per week are limited to slots divided by those weeks times survivors.
Which flush count: when your starts fit the room it runs the count with the highest profit per block; when they would overfill it, the count with the highest profit per slot-week.
Cash: blocks and fixed costs are paid the week they happen; income arrives in the week of each harvest. Real customers pay later than that, so treat the low point as a minimum.
Not decided: species, substrate, temperature, humidity, sterilisation, food-safety and licensing rules, which vary by place, demand and price for your volume, spent-block disposal, equipment, taxes and any cost you do not enter. Yields and prices come from you and your own records.

Common questions

How many flushes should I take from each mushroom block?

It depends on whether fruiting-room space is the limit. If the room has spare slots, keep harvesting while each extra flush still earns more than its harvest labor. If slots are the limit, the right count is the one with the highest profit per slot-week, which is usually fewer flushes because the later ones are small but still occupy the space. The page shows both.

How many blocks can my fruiting room carry?

Slots divided by the slot-weeks each surviving block uses: weeks to first flush, plus the gaps between further flushes, plus turnaround, all times the share that survive incubation. The page gives the largest whole number of blocks you can start per week and warns when your plan needs more.

How much cash do I need before the first sale?

Blocks are paid for at the start, but nothing sells until incubation and the first flush are done. The page simulates week by week and prints the lowest cumulative cash point, the week it happens and the week cash turns positive again.

What contamination rate can I afford?

The page solves for the contamination rate at which a started block earns exactly zero, given your yields and price, and shows a table of weekly profit across contamination and price so you can see the cliff.

Does it store my numbers or contact anyone?

No. It runs in this browser tab, saves nothing and sends nothing. You can download the week-by-week plan as a CSV.