Harvest a Psilocybe cubensis mushroom when the thin veil under its cap starts to stretch or tear, before the cap opens flat and drops its spores. Twist it out by the base. A study of stored mushroom material found the least breakdown of psilocybin in mushrooms that were dried and then kept in the dark at room temperature, and the most in fresh mushrooms that were frozen.
Check the law first. In the Netherlands and most other countries, harvested mushrooms that contain psilocybin are illegal to possess, fresh or dried. Drying them does not change that. See the legal notes.
Signs that a mushroom is ready
A young cubensis has a rounded cap that is closed around the stem by a pale skin, the partial veil. As the mushroom matures, the cap expands, the veil stretches thin and then tears, leaving a ring on the stem. The instructions with grow kits use this as the signal.
| Stage | Cap | Veil | Action |
|---|---|---|---|
| Growing | round, closed | intact, thick | wait |
| Ready | rounder and larger, edge starting to lift | thin, stretched or just tearing | harvest |
| Late | opening, flattening | torn, ring on the stem | harvest now |
| Over | flat or turned up | gone; dark spores on the kit and caps | harvest; wipe spores off the bag |
Dutch-Smart's advice is to harvest just before the veil begins to tear, and the FreshMushrooms leaflet says to harvest before the first spores begin to fall. Late mushrooms are still mushrooms, but the dark purple-brown spores coat everything in the tub, and a carpet of spores on the substrate makes it harder to spot contamination later.
You do not need to harvest a whole flush at once. Mushrooms in one flush mature over a few days; pick each one when it is ready. Once all are picked, the kit goes into its cold soak, described in the grow guide.
How to pick
- Clean hands. Wash your hands or wear clean gloves. Anything you bring into the tub can start a contamination.
- Hold the base. Take the mushroom low on the stem, where it meets the substrate.
- Twist and pull. Turn it a quarter turn and lift. It should come out whole with a little substrate at the bottom.
- Clean the stem. Cut or brush the substrate off the stem base outside the tub.
- Tidy the tub. Remove stem bases, small dried-out mushrooms and any loose bits. Leftover tissue rots.
Do not cut mushrooms off at the surface and leave the stubs: they decay in the tub. Do not eat or keep mushrooms that show spots, slime or mould, and do not harvest from a kit that has green or orange contamination.
What research says about drying and storage
Fresh mushrooms are mostly water and spoil within days, even in a fridge. Drying is how they are usually preserved. One study compared how psilocybin and related compounds in P. cubensis held up under different storage conditions (Gotvaldová et al., 2021):
| Condition | Result |
|---|---|
| Dried, stored dark at room temperature | lowest breakdown of the tryptamines |
| Fresh, stored frozen at minus 80 °C | highest breakdown |
| Spores | no tryptamines detected |
So a freezer is the wrong place for fresh mushrooms. Handle the harvest gently as well: the blue colour of a bruise is made of psilocin that has been oxidised (Lenz et al., 2020).
Drying, in practice
There is no published study comparing drying temperatures for cubensis, so we give no exact number. The aim is to remove water quickly with moving air and only mild warmth.
- Airflow first. Spread the mushrooms on a rack or kitchen paper, not touching, in front of a fan. Turn them once a day. Larger mushrooms can be split lengthwise.
- Food dehydrator. Use the lowest heat setting. Check every few hours; mushrooms of different sizes finish at different times.
- Not the oven. Ovens run hot and unevenly, and the smell fills the house.
- When are they dry? Fully dry mushrooms snap cleanly. If a stem bends, it still holds water and can go mouldy in storage.
Storage
Store dried mushrooms in an airtight glass jar in a dark cupboard at room temperature, which matches the condition with the least breakdown in the Gotvaldová study. A sachet of silica gel in the jar keeps them dry. Label the jar with the date and the strain, and keep it out of reach of children and pets: dried mushrooms look like ordinary food.
Before anyone eats them
Mushrooms from one kit can differ a lot in strength. Researchers growing 14 strains under identical conditions still found large differences between single mushrooms of the same strain (Sharchaton et al., 2026). The Trimbos Institute's drug information site explains effects, risks and dangerous combinations; read it before anyone takes them. Only adults, never alone the first time, and never before driving.
The spent kit
When a kit stops producing or turns green, close the bag and put it in the household waste. Clean the shelf with alcohol before the next kit goes there. The kit guide helps with the choice of the next one.