STEP 14. What is rehydration? What is flushing? Why is it necessary to soak mushroom cake immediately after harvesting? How to rehydrate mushroom cake and trigger new rich flush of mushroom fruiting cycle

Mushroom cake soaking. Mushroom block soaking
Mushroom cake rehydration to trigger new flush of fruiting

STEP 14. Day 32-33. How to soak magic mushroom cake and initiate new flush of fruiting

During the first flush and after harvesting you can see the mushroom cake is shrunk. Each container has from 1/2 inch to 2 inch gap from the sides of the tub. But they were flush at the beginning. What's going on?

Mushrooms absorb water from your cake. A lot of moisture evaporate from the top layer. Hence, mushroom cake/block lost moisture and shrunk. Rehydration (aka soaking in water or spraying water on the top layer) makes up for the loss of moisture. It works for mushrooms as a trigger for fruiting in the same way as rain in nature

Why do magic mushroom cakes need rehydration?

1️⃣ As you know, mushrooms consist of 90-95% water. No moisture - no shrooms.

2️⃣ During colonisation period (in incubator) and fruiting period (in fruiting chamber) mushroom substrate loses moisture that is so important for development mushroom bodies.

3️⃣ Spawn and Bulk substrate can be dry. Therefore some growers practice rehydration even before the first flush in case top layer isn't wet enough. Or if colonisation period (in incubator) lasts more than 3 weeks.

4️⃣ To start new phase of fruiting we need to simulate a long rain for our mushrooms. Every mushroom hunter knows - the best time to set out to look for mushrooms - after a good rain. If nature already has everything in place and in right order, then in our simulated conditions we still have to work hard.

5️⃣ Rehydration stimulates new flush of fruiting.

6️⃣ Rehydration helps to harvest more mushrooms and more weight of shrooms.

7️⃣ The main purpose of rehydration is moisture compensation wasted by the mycelium. You need to fill all cakes with water, so that mushrooms really begin to grow like after rain.

When do we need to soak mushroom cake?

1️⃣ Before the first flush, if your cake is totally dry. Recommended for PF-tek cakes after colonization and small mushroom cakes if colonization lasts 2 weeks and more.

2️⃣ After the first flush of harvesting is must have for any tek of cultivation: pf-tek, small mushroom cakes, bottle-tek, shoeboxes, monotub

3️⃣ Repeat rehydration after each harvesting to initiate new flush of fruiting

Prepare mushroom cake for dunking in water

1️⃣ Remove all mushrooms (even the smallest ones) and their stumps from the cakes. Mushroom cake should be completely bald.

Magic mushroom cake preparation for rehydration
Mushroom cake preparation for rehydration (Brazil)

If you have dry crust of overlay on the cake you can scrap it with sterile fork. It helps to provide access of air and water for mushroom growth. Details: Overlay & Stroma

2️⃣ Check your cakes from all sides. If you take the cake out of the box you can find some mushrooms on the sides. Remove them also.

Cultivation magic mushrooms. PF Tek guide. Mushroom cake preparation for rehydrating
Mushroom cake preparation for rehydrating


3️⃣ Rinse each cake thoroughly under the running water.

Rinse mushroom cake under running water before rehydration
Rinse mushroom cake under running water before rehydration


4️⃣ Put the cake back in the plastic container (wash this container before).

Psilocybin mushroom cake ready for rehydrating
Magic mushroom cake ready for rehydrating

How to soak mushroom cake in water?

For soaking mushroom cake use clean drinking water. You can also use chilled boiled water or just tap water

Fill each box with water. Rehydration process for magic mushroom cake
Dunking magic mushroom cake


Pour water over the cake

Growing Psilocybe Cubensis mushrooms at home. Rehydration technique. Pour water with honey (or sugar) over the cake
Soaking mushroom cake. Pour water over the cake

5️⃣ Cakes are lightweight. When you fill them with water they will float. You have to submerge each cake completely in water! Put something on top of the cake. This can be any jar or glass of water. Repeat it with each mushroom cake

Submerge magic mushroom cake completely in water
Submerge psilocybin cake completely in water. Put smth on the top to press the cake


6️⃣ Leave mushroom cakes for soaking in water for 5-8 hours at room temperature

Leave psilocybe cubensis cake for soaking (12-24 hours) at room temperature
Leave mushroom cake for soaking (12-24 hours) at room temperature


Less attractive, but handy option to use larger containers for soaking cakes. Fill them with water, add cake and put a weight or a lid on top

Rehydration mushroom cake in bigger containers
Rehydration mushroom cake in bigger containers


Some growers provide cold shock for cakes at this stage. They soak cakes in the refrigerator or add ice in water. We don't use cold shocking for rehydration process. At this stage stress for cakes can slow down the new fruiting phase, mushroom pins can stop development, as a result many mushroom aborts are formed. Actually about 10% of aborted mushrooms after rehydration is considered normal

🔴 Recommended: All you need to know about Cold Shocking

🔴 Recommended: Mushroom Aborts

7️⃣ After 5-8 hours of soaking drain the water from the container. Take cake out of the container. Rinse each cake thoroughly under running water once again.

Rinse magic mushroom cake after rehydration under running water
Rinse psilocybe cubensis cake after rehydration under running water


8️⃣ Don't put the cake back into the plastic container. Put it on the upside down container as a podium to allow mushrooms to grow from the sides. In such way cakes won't contact directly with water in fruiting chamber. Also it will be convenient to take them out for cropping

9️⃣ Wash your fruiting chamber thoroughly before placing mushroom cakes for the new phase of fruiting.

🔟 Pour one glass of water (200 ml) with 5-10 ml of H2O2 hydrogen peroxide solution 3% in your growbox and put in mushroom cakes after rehydration in the fruiting chamber again.

Psilocybin mushroom cakes in growbox after rehydration
Psilocybe cubensis cakes in growing box after rehydration

Dunking mushroom cake in honey water

Honey water recipe for dunking mushroom cake
Honey water recipe for soaking mushroom cake

I will say right away that such method has advantages and disadvantages!

Honey water recipe for soaking mushroom cake

Add only 1 teaspoon of honey per 1 Quart (1 liter) of clean water. Stir thoroughly!

Honey water for soaking mushroom cake
Honey water for dunking mushroom cake

Prepare as much as you need for dunking your cakes. Pour honey water over cake.

Growing Psilocybe Cubensis mushrooms at home. Rehydration technique. Pour water with honey (or sugar) over the cake
Rehydration process. Pour water over the cake


Flush by flush mushroom cake loses nutrition resources. That's why honey water can be as additional support for mycelium and further fruiting, especially on the last flushes. As a result we can prolong fruiting period.

Honey water (or light malt extract, or dextrose) soaking benefits based on a few practical experiments.

However we can face with another issue. Bacteria/yeast love all types of sugars (carbohydrates) and you can provoke bacterial/yeast contamination. Although I didn't have contamination in my own experiments, but it's great potential for substrate bacteria.Moreover, mushroom metabolism can be 'confused', because mycelium need time for adaptation to another type of carbs (from spawn carbs to honey carbs, that have different form). As it takes time, bacteria/yeast can use this moment. Maybe mycelium 'memory' works better if you inoculate jars with liquid culture based on honey, so that mycelium can match previous early experience for metabolism. All of the listed above is just my guessing!

Please, share your thoughts, experience and scientific arguments regarding adding carbs (honey, LME, dextrose etc.) for soaking in comments to this article

Soaking mushroom cake in alkaline water

Flush by flush mushroom cake is gradually acidified by mushroom waste products. Acid substrate (lower than 7.0) is extremely vulnerable for green mold contamination aka Trichoderma.

pH scale
pH scale

Trichoderma mold prefer acidic soils pH 4-6. After the first flush substrate pH can change gradually from 7.5-8.0 from the very beginning to 5.0-6.5 after the first flush

That's why the risks to catch green monster is higher with the next flushes, when pH drop from 7.5-8.0 to 6.5 and lower

🔴 Recommended: How soil pH affect Trichoderma

One of the methods to reboot pH level for mushrooms is rehydration in alkaline water pH 8.0 - 9.0 and adding new layer of pH adjusted casing (about 0,5 cm) after rehydration to protect mycelium.

By rehydrating the mushroom cake with pH adjusted water the pH back up to a level that is hostile for Trichoderma, but allows mycelium to thrive and produce fruits again. Although sudden changes in pH can damage the beneficial bacterial colonies in substrate!

How to prepare pH adjusted water for soaking mushroom cake?

Your local tap water may be naturally hard and alkaline (containing calcium, magnesium, carbonate), which adds further to the higher pH (7.2-7.8). Tap water may also be acidic (5.0-6.5).

Pure or distilled water has a pH level 7.0, which means it is neutral.

If you want to increase the pH of water use:

1 gallon (~4L) of tap water (or clean drinking water or distilled water)

1/8 to 1/4 tea spoon of hydrated lime (it is soluble in water). Start with 1/8 tsp!

Pure Calcium Hydroxide (Slaked Lime) 50g/2oz $7.99

Laboratory-Grade Calcium Hydroxide 500g $22.49

Shake it thoroughly and leave it at least for 1 hour to breakdown and dissolve lime in water.

Check the pH level. It should be around 8.0-9.0. If it is too low add just a pinch of hydrated lime and repeat shaking and sit time before measuring pH level again. Keep repeating a one pinch process till you can get up to 9.0 pH.

More than 9.0 can be harmful for mycelium metabolism, also harmful for beneficial bacteria in substrate

Let water sit overnight to stabilise pH (optional) or use pH adjusted water the same day for rehydration.

⛔️ Baking soda not allowed for pH adjusting for fungi!

How to check water ph?

Test the pH of your water with pH test strips or pH meter:

pH Test Paper 1 to 14 for water, soil, body $6.55

pH Test Strips 0 to 14 for Water & Liquids $11.97

Digital PH Tester for water $12.99

How to make rehydration for MonoTub or shoebox or bottle-tek

Pour cold water on the tub/shoebox/bottle directly.

Soak for 3-6 hours for rehydration the block. Drain the water.

Some growers rinse and soak monotub/shoebox block in cold water only for 10-20 minutes

Maintain proper fruiting conditions and wait for the new flush. Ready!Sometimes good misting or spraying water on the top layer till small puddles appeared is enough to trigger the new flush of fruiting

🔴 Recommended: DIY MonoTub, Automated MonoTub, Shoeboxes, Twin Tub

🔴 Recommended: Bottle-tek or How to grow mushrooms in plastic bottle

🔴 Recommended: DIY GrowBox for mushrooms

How to rehydrate Panaeolus aka Copelandia mushroom cake

Don't soak in water Panaeolus (aka Copelandia) mushroom cake! The top casing layer for Panaeolus cultivation is a mix of soil for cacti and sphagnum, main fruiting substrate is manure. If you soak such cake in water it loses the shape and turns into mud.

For Panaeolus rehydration just spray water on the top layer till small puddles appeared. Maintain proper fruiting conditions for Copelandia and wait for the new flush.

What if mushroom cake has strange smell during or after soaking

If you feel a smell of something fermented, rotted, cider, vinegary, sweet and sour, stale, yeasty, smell of dirty socks, alcohol — all these are clear signs of fermentation (bacteria/yeast contamination). It is a common issue if you had mild bacteria contamination in grain spawn before making mushroom cake/block. High temperature and water speed up fermentation process.

Fermentation — the state of actively growing microorganisms, usually in a liquid environment. Smell is a good indicator of fermentation, it starts out with a sweet vinegary odor and then turns to a denatured alcohol smell. Fermentation in cultivation is a sign of contamination. The bacteria are breaking down the yeast and causing the fermentation of the tissue

🔴 Recommended: Mycology Glossary & Mushroom Growing Abbreviations

Mild smell is not a problem. To prevent such fermentation process add 10-20ml H2O2 hydrogen peroxide solution (3%) per 1 Quart (1 liter) of water. Shake it well and use for soaking mushroom cake no more than 8 hours. But if your cake totally healthy don't use H2O2, because it inhibits useful microorganisms and mycelium as well. If you notice visible signs of contamination i.g. slime, rotted areas and strong smell, then toss mushroom cake or bury it in the garden!

🔴 Recommended: Wasted mushroom cake: carry on or throw away

Fruiting conditions after dunking Cubensis mushroom cake

✅ Temperature +20°..+25°C or 68-77°F

✅ Relative humidity 90-92% (possible range 85%-95%)

✅ Light 12 hours on/off cycle

✅ Fresh air exchange 4-6 times a day for 2-3 minutes. Or turn on air pump 24/7. Or turn on PC fan for 1-2 minutes every 2-4 hours

The next flush are going to develop faster. In 2-7 days you'll see new pins and mushroom bodies on the cakes. In 7-14 days it's time for new crop.

Now looking forward for the next flush of fruiting Psilocybe Cubensis mushrooms!

Move on — Step 15. Day 38-41. Second flush of fruiting and harvesting Psilocybe Cubensis 🔽

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