Grow calculators
Plan the batch before you mix it.
Three calculators built on the numbers Michael used on the Phoenix floor. The basic answer is free. Add your email for the full breakdown and a printable batch sheet.
01
Substrate hydration
How much dry mix and how much water a batch of blocks needs at your target moisture. Michael's working range is 50 to 60 percent, adjusted for the humidity where you grow.
The Lion's Mane block is 10 lb wet.
Within Michael's 50 to 60 percent range.
02
Spawn rate
How many grain bags a run of blocks needs. Michael's rule is 20 blocks per grain bag; with clean technique he stretches a bag to 30 or 40.
Grain bags at 20 per bag
5bags
Spawn per block
1/20bag
03
Yield and biological efficiency
Biological efficiency is fresh mushrooms divided by the dry weight of the substrate they grew on. Enter the block as filled and its moisture; the calculator works out the dry weight. The default is Michael's shiitake figure: about 3 lb first flush off a 10 lb block.
Biological efficiency
67%
Fresh harvest, all blocks
30lb
The numbers come from the books
The calculators give you the quantities. The books give you the method.