Buy Grain Spawn: Organic Mushroom Spawn for Your Own Growing
Grain spawn is the “seed” of your mushrooms: cereal grains fully colonised by mycelium. We produce it fresh at our organic mushroom farm – for straw pellets, buckets, coffee grounds, straw bales, wood or logs.
- EU organic certified
- Freshly made in Schleedorf
- 2 kg for approx. 20 kg substrate
- Guide via QR code
Which mushroom species suits you?
Temperature and substrate matter most. For beginners we recommend the oyster mushroom.
Oyster mushroom
Robust, fast and successful on almost anything – from straw bags to garden beds.
- Fruits cool: 5–20 °C
- Ideal in spring and autumn
- 2–4 flushes
Summer oyster mushroom
The blue oyster mushroom loves warmth and needs no cold shock.
- Fruits at 11–28 °C
- Finer and milder than the oyster mushroom
- 2–3 flushes
Lemon oyster
Bright yellow clusters with a slightly fruity flavour – for warm temperatures.
- Fruits at 16–25 °C
- On straw, coffee grounds & more
- 2–4 flushes
King oyster
Thick, meaty texture reminiscent of porcini, keeps well after harvest.
- Fruits at 15–21 °C
- Best on hardwood pellets
- 1–2 flushes
Shiitake
The classic with intense umami – on wood substrate in filter bags or on logs.
- Fruits at 10–25 °C
- Long maturing phase: 60–100 days
- 2–4 flushes
Methods: which grain spawn for which method?
Tap a method to open the detailed guide.
| Method | Oyster | Summer oyster | Lemon oyster | King oyster | Shiitake |
|---|---|---|---|---|---|
| Straw pellets in bags | ✓ | ✓ | ✓ | ○ | – |
| Straw in a bucket | ✓ | ✓ | ✓ | – | – |
| Coffee grounds | ✓ | ✓ | ✓ | – | – |
| Straw bales in the garden | ✓ | ✓ | ✓ | ○ | – |
| Mushroom bed (German) | ✓ | ✓ | ✓ | – | – |
| Hardwood pellets in filter bags | ✓ | ✓ | ✓ | ✓ | ✓ |
| Logs | ✓ | ✓ | ✓ | – | ✓ |
✓ well suited · ○ possible, lower yield · – not recommended
Ideal conditions by species
| Species | Colonisation | Fruiting initiation | Fruiting | Flushes |
|---|---|---|---|---|
| Oyster mushroom | 20–24 °C, 14–22 days | 6–15 °C, 90–95 % RH | 5–20 °C, above 85 % RH | 2–4 |
| Summer oyster | 20–24 °C, 14–22 days | 15–20 °C, 90–95 % RH | 11–28 °C, above 85 % RH | 2–3 |
| Lemon oyster | 20–24 °C, 14–22 days | 16–25 °C, 90–95 % RH | 16–25 °C, 85 % RH | 2–4 |
| King oyster | 20–24 °C, 10–15 days | 10–15 °C, 95–97 % RH | 15–21 °C, 85–90 % RH | 1–2 |
| Shiitake | 20–24 °C, 60–100 days | 10–16 °C, 90–95 % RH | 10–25 °C, above 85 % RH | 2–4 |
RH = relative humidity. Values from the book “Faszination Pilzzucht” by Sebastian Reindl (Stocker Verlag) and from our own practice at the farm.
How to use grain spawn
Using straw pellets – the easiest way to start:
- Keep cool: Store at 1–3 °C until use; in the fridge it keeps a little shorter.
- Prepare substrate: Pour boiling water over straw pellets and let cool below 35 °C.
- Inoculate: Mix in about 10 % grain spawn – 2 kg is enough for approx. 20 kg of moist substrate.
- Colonise & harvest: Let it colonise at 20–24 °C, then initiate fruiting and harvest.
Read more: How to inoculate mushroom substrate · Common mushroom growing mistakes. Every product comes with a step-by-step guide – also via the QR code on the label.
FAQ: grain spawn
How much grain spawn do I need?
As a rule of thumb, about 10 % of the moist substrate weight. A 2 kg pack (approx. 3.5–4 litres) is enough for around 20 kg of moist substrate – or one straw bale of 50 x 50 x 100 cm.
How long does grain spawn keep?
Refrigerated at 1–3 °C for about 1–2 months, a little shorter in a normal fridge (4–8 °C). It grows best when used fresh.
Which grain spawn is best for beginners?
The oyster mushroom: it grows fast, forgives mistakes and works on many substrates. For warm rooms or summer, choose the summer oyster mushroom.
Can I use grain spawn for logs?
Yes, for example with the column method. For logs, plug spawn is often easier to handle.
Why is my substrate not colonising?
Common causes: substrate too warm when inoculating (above 35 °C), too wet or too dry, too little spawn or a room that is too cold. Details are in each guide.
Do you supply commercial quantities?
Yes. Request our price list for mushroom farms via the contact form.
From our organic mushroom farm in Schleedorf
We produce our grow kits, grain spawn and plug spawn ourselves – at our EU organic certified mushroom farm in Schleedorf near Salzburg, Austria. Short distances mean fresh, vigorous mycelium for you.
Sebastian Reindl, founder of Stoff'n, is the author of the book “Faszination Pilzzucht” (Stocker Verlag). Its know-how goes into every one of our guides.
More for your mushroom growing
Questions? We are happy to help
Something not growing as expected?
Check the matching guide and our FAQ – or write to us via the contact form, ideally with a photo. We will get back to you personally.
