Stage 4 of 6 · 4–8 days
Fruiting
Carrying pins through to mature mushrooms: more fresh air, steady humidity, dry caps, and watching for problems.
Signs you're at this stage
- Pins are pea-sized or bigger and clearly growing each day.
- Caps are separating from stems and the first fruits are a few centimetres tall.
What changes after pins
Growing mushrooms breathe out a lot of CO₂ and use a lot of water. The job now is to give them more fresh air than during pinning, keep the walls and air humid, and keep the caps themselves from staying wet. Most of the size a fruit will reach is put on in its last few days.
The numbers
- Air temperature
- About 70–78 °F (21–26 °C), avoiding daily swings of more than about 5 °F
- Humidity
- About 85–92%, enough that the surface still beads, not so much that caps stay wet
- Fresh air
- More than at pinning; fan or open up 2–3 times a day in passive setups (Bible, p. 112)
- Light
- Keep the 12/12 cycle; too little light gives long stems and small caps
- Misting
- Walls and lid only, about 20 sprays a session in a shotgun chamber (Bible, p. 112)
- Pins to harvest
- Roughly 4–8 days for cubensis
Daily routine
- Look at the surface first. Dewy and beaded is good. Matte means mist the walls. Puddles mean drain or wipe them and cut back.
- Fan out stale air gently, or check that passive holes are clear.
- Check each cluster for the harvest cue so nothing drops spores overnight.
- Pick off any , dark pins that stopped growing, so they do not rot in place.
- Close up and leave it.
What the fruits tell you
- Long thin stems, small capsUsually: Not enough fresh air, or too little lightDo: Fan more often or open more holes; check the light reaches the tub
- White fuzz at the stem basesUsually: : CO₂ high, often with a very wet surfaceDo: More fresh air. Harmless in itself; it is not cobweb
- Cracked, scaly or leathery capsUsually: Air too dry, under about 85% RH, or air blowing on fruitsDo: Raise humidity, mist walls, move the tub away from vents
- Yellow-brown sunken spots on capsUsually: from caps staying wetDo: Stop wetting caps, add air so they dry, pick spotted fruits
- Many pins darkening and stoppingUsually: A dry surface, a temperature swing or too many pinsDo: Restore surface dew, steady the temperature; pick the aborts
- Fruits leaning one wayUsually: Growing toward light or toward the fresh airDo: Normal. Even out the light if it bothers you
Blue is usually fine
Fruits and cakes that are handled or knocked turn blue where they were touched. That is , a chemical reaction in the tissue, and it is normal (Bible, p. 112). Blue that keeps spreading across a cake, especially with powder on top, deserves a closer look under contamination ID.
Common mistakes
- Spraying the mushrooms instead of the walls.
- Letting a fan blow directly onto the fruits.
- Waiting for every fruit in a flush to be ready, so the first ones drop spores.
- Assuming blue bruising is mould.
What to do next
- When caps open and the veil starts to stretch and tear, harvest. See harvest timing.
- Anything colored and powdery on the substrate: see contamination ID first.
Seen something different in your own tub? Add your grow report on the strain you grew. Reports are how these pages get better.
Sources
- Psilocybin Mushroom Bible (Haze & Mandrake, 2016), misting and fanning routine, p. 111–112
- Psilocybin Mushroom Bible (Haze & Mandrake, 2016), bruising on cakes, p. 112
- The Mushroom Cultivator (Stamets & Chilton, 1983), cubensis growth parameters, p. 196–199
- The Mushroom Cultivator (Stamets & Chilton, 1983), wet caps and blotch, p. 155
- Shroomery forum: high CO₂ readings in a monotub
- Shroomery forum: fruiting temperature discussion
Written for this site in our own words from the books and threads above. Where growers disagree, both sides are given. Nothing here is advice about anything other than growing.