Cultivation Theory: A Brief Summary of Low Tech Growing of Oyster Strains

Aloha Medicinalsperformed an experiment a few years ago to find the most effective combination of low tech pasteurization and strains to provide the highest yields for the lowest cost, as well as comparing the benefits of shredding the straw substrate to not shredding it. The strains we'll cover in this summary are as follows:

Pleurotus pulmonarius AX

Pleurotus ulmarius Elm A

Pleurotus sajor-caju AM1

Pleurotus djamor AM1

And the pasteurization methods:

A control group sterilized with steam in a autoclave
A water bath with Hydrated lime
A water bath with a bleach mixture
A water bath with standard clothing washing powder

The straw was prepared and inoculated as per the guidelines detailed in our Steam inoculation procedure, with the exception of the un-shredded straw which was used whole instead of being run through a grinder, and the replacement of hydrated lime with the other treatment chemicals mentioned above.

Across the board Aloha found shredding the straw was always the best option. Running the straw substrate through a grinder of any short before treatment and inoculation reduced the incidents of contamination and speed growth tremendously. This is in part due to the increased coverage of the pasteurization method and the increased ease of packing the substrate tightly into the grow bag. The graphs below show these results, notice the extremely stark contrast between the two.

The results were quite interesting. When treated with Washing powder and bleach, strains performed very similarly producing around 130% Biological Efficiency* for the pulmonarius and ulmarius, and near 100% BE for The djamor and sajor-caju strains.

These numbers rise sharply when you look to the steam control and hydrated lime examples, with 170%+ BE for the ulmarius strain in both cases, 170% BE for the djamor strain grown on the straw treated with hydrated lime, and near 125% BE for sajor-caju and pulmonarius strains for both treatments. The results are clear; the stand out treatment across the board is the hydrated lime. Even Aloha was surprised that this treatment outperformed or was dead even with the steam control. This is why we suggest this particular treatment for any beginner or frugal mushroom growers. These numbers are displayed below in Figure 2.

*Biological efficiency (BE) is calculated by comparing the raw weight of harvested fruit bodies to the wet weight of substrate used. Example: 6 pounds of wet substrate produces a biological efficiency of 150%, so 9 pounds of mushrooms were harvested over the substrates lifetime.

The strains themselves showed a large degree of variability however all were chosen for their strong and fast growth and quick fruiting. These are all excellent strains, however Pleurotus ulmariusELM A and Pleurotus djamor AM1 are the clear standouts. Both provide very tasty fruit bodies and are a breeze to grow and if done right provide some of the highest biological efficiencies this writer has ever seen.