Growing Troubleshooting

Black spots on Mushrooms and Mycelium

Strange black spots suddenly appeared on mushroom caps and mycelium. Why is this happening? Is it contamination or not? Is it safe to take such mushrooms?

Why dark spots appeared on mushroom caps and mycelium
Mushroom caps and mycelium turned black

Strange black color on mushroom caps and mycelium

You can observe such dark spots on mushroom caps and mycelium right after torn veil. Since this moment sporulating phase is started. It is vital importance for mushrooms to spread all mature spores and continue fungi life

Black spots on mushrooms and mycelium: contamination or not?

The color of fungi spores are black-violet or brown-violet. At first spores appear on the torn veil and mushroom stem.

Fungi spores on stem and torn veil
Mushroom spores (brown-violet color) on stem and torn veil. It's normal!

If you leave mushrooms on the cake to sporulate for 1-2 days they drop huge amount of spores on the substrate, other cakes, mushrooms and even walls of fruiting chamber. Total mess at first glance looks like contamination. Extreme sporulating aesthetically looks unattractive.

Spores on mushroom cake
Spores everywhere in fruiting chamber: on mushroom cakes, on mushroom caps and walls of the growbox. Photo by mrzimm - Shroomok Growers Community on Discord

Newbie growers often confuse such case with black mold contamination, inky cap disease or bacteria contam.

Usually noobs so surprised and scared to see "horrible" changes that can appear just a few hours after or one day after

"Holy black crap - is this the nasty stuff I think it is? Wwwaaahhhh"

Dark spots of spores on mushroom cake after harvesting
Black spots of spores on mushroom cake after harvesting. Photo by angeline - Shroomok Growers Commmunity on Discord

When realised it's just spores:

"OMG what a f*vking noob I am! Not black mold but SPORES! Took three (shrooms) this size out of tub… they all looked like this - spores ejected! Hahahaha learning - all the time learning"

Harvested mushroom that started sporulating
Harvested mushroom that started sporulating. Photo by angeline - Shroomok Growers Commmunity on Discord

Nothing to worry about, grower! It’s not contamination, just mushroom spores create such layer

Mushrooms spores on mycelium and shrooms. Is it safe or not?

Since torn veil mushrooms stop their growth. Spores spreading in the air. After sporulating fruit body become useless, life cycle closed.

Spores released on mushrooms and mycelium
Spores released on shroom caps and mycelium. Hurry up!

After spore releasing, the process of decomposition of the fungus cells begins. Mushroom body literally dying and slowly loses its quality and potency. That's why no sense to wait too long. Moreover, it influences pin development of the next flush and can provoke contamination.

Mushroom sporulating
Mushroom caps turned black with spores. Hurry up!

In fact we wait for torn veil if we are going to make spore prints.

🔴 Recommended: How to make magic mushroom spore print

It's too late to make spore prints after releasing spores, because they are mostly on caps and mycelium.

Spores on mushrooms and mycelium
Spores on caps and mycelium. Photo by mrzimm - Shroomok Growers Community on Discord

If you don't need prints you can crop your mushrooms anytime: before torn veil, or right after torn veil.

For consuming I crop shrooms earlier, before torn veil. Such mushrooms are denser and taste better to me IMHO

There is one more reason to avoid such rich sporulating. Spores create a layer on mycelium and inhibit pins development.

Mushroom sporulating phase
Spores on mushroom caps and cake. Photo by Leo - Shroomok Growers Community


The last point. If the fruiting bodies begin to rot, it can lead to contamination of the entire mushroom cake/block.

Spores on mushrooms and mycelium
Spores on mushrooms and mycelium

Beautiful cases of mushroom sporulating

Right after torn veil air currents carry spores and deposit them on the tops of the caps and sometimes creating beautiful arts.

Mushroom art
Spores art on mushroom caps


Such mild signs of sporulating on mushroom caps is totally normal and cute

Mild sporulating on mushroom caps
Mild spores signs on mushroom caps


Check out spores on gills under the microscope. Here are the billions of spores produced by mushroom fruit body

spores on gills under microscope
Spores on gills, microscopy

Spores of Golden Teacher for microscopy use

Spores of P. Cubensis Golden Teacher, microscopy use
Spores of Psilocybe Cubensis Golden Teacher, microscopy. Photo by mrzimm - Shroomok Growers Community on Discord


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Have a happy growing and harvest your shrooms in time!

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