🍄 Free tool · no sign-up · saved on your device

Mushroom Grow Log

Stop tracking grows in a messy spreadsheet. Add a batch, move it through each stage, and Mycro works out your biological efficiency, how long each batch has been running, and your contamination rate — automatically. It starts with sample batches so you can see how it works; edit or clear them anytime.

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Active batches
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Blocks in production
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Avg biological efficiency
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Contamination rate

+ Add a batch

Anything that helps you find it.
Dry weight, before water. Used for biological efficiency.
This log lives in this one browser. Mycro is the full version: your grow log synced across phone & laptop, automatic cloud backup, your real BE and contamination patterns per strain and substrate over months, harvest calendar, and COGS — so nothing is lost when a laptop dies or you grow past a spreadsheet. Join the early-access list:

How the grow log works

A grow log is just disciplined memory — but the value is in the numbers it lets you compute. Here's exactly what this tool tracks and how.

The five stages of a batch

Every batch moves through the same path. Tap the stage button on a batch to advance it; the log timestamps the move and shows how many days it has spent in each stage.

StageWhat it meansTypical duration
InoculatedSpawn mixed into sterile substrate, just sealed.Day 0
ColonizingMycelium running through the block in the dark.Oyster 10–14d · King/Lion's Mane 14–21d · Shiitake 30–60d
FruitingMoved to fruiting conditions; pins forming, mushrooms growing.7–14d to first flush
HarvestedPicked — record total fresh weight to lock in biological efficiency.+ later flushes
ContaminatedLost to green mold, bacteria or another contaminant.Counts toward your loss rate

Biological efficiency (the number that matters)

When you record a harvest, the log computes biological efficiency = fresh yield ÷ dry substrate weight × 100%. Track it across batches and you learn the real BE for your strain, substrate and room — which is what tells you whether a project actually pays. See the biological efficiency guide for target ranges, and the Grow Calculator to plan a batch before you start it.

Overdue flags & contamination rate

If a batch sits in colonization longer than is typical for its species, the log flags it — usually the first sign of a slow strain or a hidden contaminant. Your contamination rate (lost batches ÷ finished batches) is tracked at the top, so you can tell whether a change to your process actually moved the needle. New to diagnosing contamination? Read the contamination ID & prevention guide.

Your data stays on your device

This free log saves in your browser only — no account, no upload. That's perfect for trying it and for a single grower on one machine. The trade-off is that it can't sync to your phone, back up to the cloud, or roll months of batches into per-strain trends — which is exactly what the full Mycro app adds.

Comparing tools? See Mycro vs MycoHub — an honest look at when a web-based grow log beats an offline phone app, and when it doesn't.

For legal culinary & medicinal mushroom cultivation only. Durations and ranges are general guidance from common practice, not guarantees.