Second Flushes (continued)

I continue to reflect upon second flushes and how to coax them out of the block after the first main flush. Interestingly, after taking action on the bags from the Italian oyster batch that originally struggled to produce the second flush, thus prompting this "investigation," a second flush has started to pin in recent days about a week after. The fact that pinning started again after re-sealing/dunking for 24 hours shows that there is clearly energy left in the blocks and it is a matter of coaxing them out properly.

Here is a re-iteration of what I've found so far. In my first blog post on this, I listed five, preliminary steps that I could take to increase the chance of better second flushes. I am re-listing them here with some additional thoughts.

Original point 1:

"Making smaller cuts - I was making large X's across the entire face of one end, which led to dried out substrate after the first harvest. A smaller X will allow the grower to place micropore tape over the X more easily which will allow for better humidity retention and recovery of the block in preparation of the block. Growers such as Southwest Mushrooms seem to be able to get away with larger cuts, but they presumably have better humidity control than I do."

This is correct, I am happy with how the smaller cuts is concentrating the growth of the oyster mushroom pins in that one area. However, there is air that seems to seep in through the opening with bags that are slightly loose, triggering pinning in areas surrounding the cut area. Since they are still behind the plastic, they cannot grow out, meaning that the mycelium is wasting energy generating pins that will not fully develop. I need to find some sort of way to keep the plastic tighter on the block so that fewer unnecessary pins form.

Original point 2:

"Making the cut in the center of the bag instead of at the end. This will allow for a larger first and second flush as the nutrients from the bag are overall at a shorter distance from the fruiting point."

This is good advice - the cut more towards the wide side gives more uniform access to the mycelium as opposed to making a cut at the end of a long side for which the opposing side is very far. No other other thoughts on this so far.

Original point 3 & 4:

"When harvesting the mushrooms, cutting the bouquets with scissors or a knife will minimize substrate loss which leads to greater surface area of dryness - although this problem may be reduced given smaller cut size and micropore tape after first harvest, rending this unnecessary"

"The grower should clean out all the dead debris from the harvest site in preparation for the second flush"

These are both good points and I will likely do this going forward to maximize the chances of getting a good second flush. Since the cuts are smaller per point 1, this should be easier as well.

Original point 5:

"As mentioned in step 1, the grower should cover the X in micropore so as to minimize humidity loss."

This is definitely a very important point - I believe the large cuts and ripping out large amounts of substrate during the harvest created a great surface area that was subject to constant air flow, and hence, easily dried out, greatly reducing the yields from a potential second flush. Then for 3 - 5 days, I should tape the bag close with micropore tape to minimize mycelium contact with air flow.

Additionally, it may be helpful to drape some sort of plastic cover the resting blocks to minimize light exposure, which also decreases air flow and increases humidity. This may be more practical than changing grow room conditions entirely as there may be other mushrooms in various stages of fruiting.

Other points:

By incorporating the above five points, it is likely that a much more successful second flush can be formed.

Regarding the injection of water into the mushroom blocks, I did try doing that in the past week, and it was very unsuccessful. It seems that the mushroom block does not absorb the water well that way and one can only inject very small amounts at a time (10 - 20 milliliters), rendering the process even more tedious than soaking.

Soaking may still be favorable, but performing all the steps above in conjunction with frequent misting, may produce a second flush big enough that renders soaking unnecessary. I do prefer to avoid soaking if possible as it is labor intensive and also brings the possibility of bacterial infection, especially if one block is already infected.

On another note, I also wonder whether there are certain key nutrients that prevent a successful flush. More specifically, I wonder whether they oyster mushrooms would be able to produce a second or third flush but for the fact that they lack one or two key ingredients.

Gypsum is often added to provide additional calcium or sulfur. In my next batch of mushrooms, I'm going to try adding it to half the batch and then see how each flush grows out depending on whether it has gypsum or not. Chat GPT does indicate that "calcium can strengthen fruiting bodies and support mycelial recover after the first flush, potentially improving subsequent yields."

We'll try all the above and see if it makes any differences...