Mushroom Yield Calculator Using Biological Efficiency
Enter your substrate weight and each flush you pick, and the calculator scores the harvest as biological efficiency. You can also run it before you start. Give it a BE figure from your records or your spawn supplier, and it estimates the harvest your substrate could give.
Result
75% BE
1.5 kg of fresh mushrooms from 2 kg of dry substrate
- Dry substrate
- 2 kg
- Fresh harvest
- 1.5 kg
- Biological efficiency
- 75%
BE compares fresh, wet mushrooms with dry substrate, so it can pass 100%.
How it works
Fresh Mushrooms Over Dry Substrate
Biological efficiency, or BE, divides the fresh weight of the mushrooms you picked by the dry weight of the substrate they grew on. Picking 1.5 kg from 2 kg of dry substrate gives 1.5 / 2 = 0.75, which is 75% BE. Because both weights scale with the batch, you can compare a small bag and a large tub on the same scale.
The top of the fraction is wet and the bottom is dry, so BE works as a comparison and does not measure a share of anything. It can pass 100% without anything being wrong. Fresh mushrooms carry a lot of water, while the dry substrate under them carries none.
If you only know the wet weight of your mix, the calculator first takes out the water. Five kilograms of substrate at 60% moisture holds 2 kg of dry material, so 2 kg goes under the line. The substrate calculator runs the same moisture math the other way, from dry weight to the water you add.
Entering each flush separately shows how the harvest tailed off. The table splits the total, so you can see how much the first flush carried compared with the later ones. If a late flush adds only a small share, you can weigh that against the shelf space the block still takes up.
Your numbers, worked through
BE % = fresh mushrooms (kg) / dry substrate (kg) x 100
- 1.5 kg / 2 kg = 0.75
- 0.75 x 100 = 75% biological efficiency
Limits
What this tool cannot do
- It cannot tell you what BE to expect from a strain. That figure comes from your own records or your spawn supplier.
- It cannot account for water lost before you weighed the harvest, so pick and weigh the same way each time.
- It is not an income or profit figure. Price, labor and sales sit outside it, and they decide which species earn money for a grower.
Questions
Why does my BE come out above 100%?
Fresh mushrooms are mostly water, while you weigh the substrate dry. Your harvest can therefore weigh more than the dry substrate under it. When BE lands above 100%, it only means the picked mushrooms outweighed that dry material.
Should I weigh mushrooms before or after trimming?
Pick one way and keep to it, then note it beside your numbers. Comparing a trimmed harvest with an untrimmed one changes BE without the grow being any different. If you sell trimmed mushrooms, weighing after trimming keeps BE close to what you actually sell.
Can I use wet substrate weight?
Yes, if you know its moisture. Choose Wet and enter the moisture share, and the calculator works out the dry weight before it divides. Without that share, a wet weight would make your BE look far lower than it really is.