Mushroom Contamination Tracker
Log a grow batch and instantly see your contamination rate, success rate, wasted yield and material cost — with a tailored diagnosis based on the contaminant type and cultivation stage.
Diagnosis & recommendation
Overview
The Mushroom Contamination Tracker turns a simple batch count into an honest picture of your grow. Whether you run grain jars on a shelf, agar plates in a still-air box, or bulk tubs in a fruiting chamber, contamination is the single biggest cause of lost harvests — and it is often invisible until it has already spread.
This tool is built for hobbyist and small-scale commercial growers who want to track batch health over time instead of guessing. Enter how many units you inoculated and how many failed, and you get your contamination and success rates, the yield and materials you lost, and a plain-language diagnosis tied to the contaminant you saw and the stage it struck.
How It Works
- Enter units inoculated — the total jars, bags or plates you started in this batch.
- Enter contaminated units — how many showed mold, bacteria or off smells and had to be pulled.
- Pick the contaminant type and stage — this shapes the diagnosis, since the fix for Trichoderma at grain stage differs from cobweb at fruiting.
- Add yield and cost (optional) — expected grams per healthy unit and your per-unit material cost let the tool estimate what the failures actually cost you.
- Click Calculate — review your rates, breakdown and tailored recommendation. Click Reset to clear and log a new batch.
Formula Explanation
The core metrics are straightforward ratios; the value is in tracking them consistently.
The batch health rating compares your contamination rate against real-world hobbyist benchmarks: under 5% is excellent (advanced sterile technique), 5–15% is a normal working range, 15–30% signals a process problem worth fixing, and 30% or higher is critical and usually points to a specific breakdown in sterilization or airflow.
Practical Benefits
- Spot trends early — a rate creeping from 8% to 20% across batches flags a problem before it wipes out a run.
- Quantify the real cost — seeing wasted grams and money makes the case for a flow hood, pressure cooker upgrade or better air filtration.
- Diagnose faster — matching contaminant to stage narrows the likely cause instead of changing everything at once.
- Compare techniques — test a new sterilization time or spawn ratio and measure whether contamination actually drops.
- Set realistic expectations — know whether your losses are normal for the method or a sign something needs attention.
Frequently Asked Questions
For hobbyists, roughly 5–15% is a normal working range and reflects reasonable technique. Consistently under 5% suggests strong sterile practice, often with a flow hood. Rates above 15% usually mean a fixable issue in sterilization, hydration or airflow, and above 30% points to a clear breakdown worth troubleshooting before your next batch.
Usually not. Aggressive molds like Trichoderma and bacterial wet spot spread through the substrate and are best removed and sealed for disposal, away from your grow space, to protect the rest of the batch. Cobweb mold caught very early at fruiting is sometimes treatable with better fresh-air exchange, but the safe default is to isolate and discard rather than risk contaminating clean units.
Each contaminant points to a different root cause. Bacterial wet spot often means under-sterilized or overly wet grain; green mold usually means airborne spores and rushed sterile work; cobweb points to high humidity and poor airflow at fruiting. Naming the contaminant lets you change the one thing most likely to be the cause instead of overhauling your whole process at once.
No — it is a practical estimate. It assumes each failed unit would have produced roughly the same yield as a healthy one, using the figure you enter. Real yields vary by species, substrate, flush number and conditions, so treat the number as a planning guide for the scale of your losses, not a precise accounting figure.
Disclaimer: This tracker is provided for general educational and planning purposes only. Its estimates rely on the figures you enter and on typical hobbyist benchmarks, and they may not reflect your specific species, substrate or conditions. It is not laboratory, agricultural, financial or safety advice. Some contaminants — including certain black and blue-green molds — can pose health risks; handle and dispose of contaminated material carefully and follow local guidance. Always use your own judgement and consult a qualified professional where appropriate.
