King Trumpet Oyster Colonized Agar Plate
King Trumpet Oyster Colonized Agar Plate is backordered and will ship as soon as it is back in stock.
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Description
Description
Fully colonized King Trumpet Oyster (Pleurotus eryngii) agar plate, grown from our master culture and 1st-generation isolated genetics — the same strain we use in our King Trumpet liquid culture syringes and grow kits. Each plate is produced fresh at our Illinois lab on standard malt extract agar (MEA), fully colonized before it ships, and ready to ship from inventory — usually within 1 business day.
Unlike most agar plate sellers who make plates to order with 2–4 week lead times, our plates are colonized and held in inventory — ready to ship from our Illinois lab. Most orders ship within 1 business day; multi-item orders may take an additional 1–2 days to process.
Why King Trumpet on Agar?
King Trumpet — also sold as King Oyster, King Brown, French Horn, or simply "eryngii" — is the largest and meatiest of the cultivated oyster mushrooms. Instead of the thin, fan-shaped caps other oysters produce, it grows thick, dense white stems topped with small tan caps, and the stem is the prize. Beyond the size, King Trumpet offers:
- Meat-like texture — the stems stay firm and chewy when cooked. Sliced into rounds and seared, they're a well-known scallop substitute; shredded, they work like pulled meat.
- Long shelf life — one of the longest-keeping gourmet mushrooms at 7–10 days refrigerated, far more forgiving than Golden or Pink Oyster for storing or selling
- Cool-to-moderate fruiting — fruits best at 55–65°F, filling the gap between Blue Oyster and the warm-weather oysters
- Heavy yields by weight — dense stems mean each flush weighs more than it looks
King Trumpet is a step up in difficulty from the other oysters — it wants a supplemented hardwood substrate and more attention to fresh air and humidity during pinning — which makes a clean, vigorous starting culture especially valuable.
Shatterproof Polypropylene Plates
Every King Trumpet plate ships in a 90mm polypropylene Petri dish — not the standard polystyrene used by most agar sellers. Polypropylene flexes under impact instead of cracking, which means your plate arrives intact even after rough handling in transit. This is a meaningful upgrade: a cracked plate isn't just a damaged product, it's a contamination risk, since a crack breaks the parafilm seal and exposes the culture to airborne contaminants. We chose polypropylene specifically to eliminate that problem.
(The exception in our lineup is Lion's Mane, which uses clear polystyrene to maximize contrast against our specialty black agar.)
What You'll Receive
- One 90mm polypropylene Petri dish, parafilm-sealed for sterility during transit
- ~18mL malt extract agar (MEA) — our standard formulation for gourmet species
- Fully colonized with healthy, bright-white King Trumpet mycelium (typically 90–100% coverage at ship time)
- 1st-generation isolated genetics from our master culture — the same strain in our King Trumpet LC syringes and grow kits
- Lab-inspected for contamination before ship
- Produced fresh at Myco Labs (Illinois, USA)
How to Use Your Agar Plate
A single colonized agar plate is one of the most versatile tools in mushroom cultivation. From one plate, you can:
- Transfer to grain — cut a small wedge of colonized agar and place it onto sterilized grain (rye, our 5-grain blend, etc.) to create grain spawn. King Trumpet typically colonizes grain in 10–14 days.
- Create liquid culture — transfer agar wedges into sterile liquid media to produce your own LC syringes
- Expand to more plates — divide one plate into 8–10 fresh plates to start a long-term genetic library
- Isolate strong sectors — pick the most vigorous growth and transfer it to a fresh plate to refine your genetics over generations
New to agar work? See our grain transfer tutorial.
King Trumpet Growing Characteristics
| Latin name | Pleurotus eryngii |
| Common names | King Trumpet, King Oyster, King Brown, French Horn, Eryngii |
| Mycelium appearance | Bright white, dense and cottony; less rhizomorphic than other oysters |
| Colonization speed on agar | Moderate — typically 7–12 days at 72–78°F |
| Preferred grain | Rye or our 5-grain blend |
| Fruiting substrate | Supplemented hardwood sawdust or masters mix — does not perform well on straw alone |
| Fruiting temperature | 55–65°F |
| Appearance | Thick white stems 2–6" tall with small tan-to-brown caps |
| Fruiting habit | Individual fruit bodies or small clusters of thick stems |
| Flavor profile | Mild, savory umami; firm, meaty texture — excellent seared, grilled, or roasted |
| Shelf life | Long — 7–10 days refrigerated |
| Difficulty | Intermediate — more demanding than other oysters |
| Use category | Gourmet (culinary) |
Plate Specifications
| Plate size | 90mm Petri dish |
| Plate material | Polypropylene — shatterproof, flexes under impact |
| Agar type | Standard malt extract agar (MEA) |
| Agar volume | ~18mL |
| Seal | Parafilm M, lab-grade |
| Sterility | Poured and inoculated under HEPA-filtered laminar flow |
Sterility & Quality Standards
Every plate is poured, inoculated, and inspected at Myco Labs under HEPA-filtered laminar flow. Plates are sealed with parafilm immediately after inoculation and incubated in a dedicated clean room until fully colonized. Each plate is visually inspected for contamination before being approved for shipment — if it doesn't look right, it doesn't ship.
Shipping & Handling
All agar plates are produced ahead of time and held in inventory — they are not made-to-order. Most orders ship within 1 business day of being placed. Multi-item orders (especially those including grow kits, grain spawn, or other made-fresh products) may take 1–2 additional business days to process so we can pack everything together. Orders placed Friday afternoon, weekends, or holidays ship the next business day.
Plates ship in insulated, padded packaging via USPS Priority Mail (typically 2–4 days in transit). In summer months (May–September) or to hot-climate destinations, we include a cold pack at no additional cost. Inspect your plate within 24 hours of arrival — minor condensation on the lid is normal and harmless. Store in a cool, dark place (55–70°F) until ready to use; an unopened, sealed plate stays viable for 60–90 days at room temperature, or 6–12 months refrigerated at 35–40°F.
Recommended Companion Products
- King Trumpet Oyster Liquid Culture Syringe — same genetics, ready-to-inject format
- King Trumpet Oyster Mushroom Grow Kit (5 lbs) — skip the lab work and go straight to fruiting
- Grain Spawn Bags — for transferring your colonized agar to bulk
- Browse All Colonized Agar Plates
Frequently Asked Questions
Is King Trumpet the same as King Oyster? What about King Blue Oyster?
King Trumpet and King Oyster are the same mushroom — Pleurotus eryngii. You'll also see it sold as King Brown, French Horn, or "eryngii." King Blue Oyster is a different mushroom: it's a large-capped strain of Pleurotus ostreatus (the Blue Oyster species) and grows like a classic oyster, with big caps and short stems. If you want the thick, meaty stems, King Trumpet is the one.
How does King Trumpet compare to Blue, Pink, and Golden Oyster?
All four are Pleurotus species, but King Trumpet is the odd one out. Blue, Pink, and Golden Oyster are fast, forgiving, and produce thin caps that fruit happily on straw. King Trumpet is slower, prefers supplemented hardwood, and needs more attention during pinning — but it rewards you with dense, meaty stems and a shelf life two to three times longer than the other oysters. Many growers start with Blue or Pink Oyster and move to King Trumpet once they're comfortable.
Can I grow King Trumpet on straw?
Not well. Unlike most oysters, King Trumpet is a poor performer on pasteurized straw alone. For best results, use supplemented hardwood sawdust or a masters mix (roughly 50/50 hardwood sawdust and soy hulls), sterilized rather than pasteurized. Fruiting in a bag with a small opening at the top helps the stems grow thick and long.
How fast do these ship compared to other agar plate sellers?
Most orders ship within 1 business day. Compare that to other agar plate sellers (including the larger names in the industry) who make plates to order, meaning you wait 2–4 weeks after ordering for the plate to be poured, inoculated, and colonized. Ours are produced on a rolling schedule and held in inventory fully colonized, ready to ship the moment you order. Multi-item orders may take an additional 1–2 business days to process so we can pack everything together.
Why do you use polypropylene plates instead of polystyrene?
Polypropylene plates flex under impact instead of cracking. A cracked plate isn't just damaged — it's a contamination risk, since the crack breaks the parafilm seal and exposes the culture to airborne contaminants. Polypropylene eliminates that problem entirely. The plates cost us more, but the result is that your culture arrives intact and uncontaminated. (Our Lion's Mane plates are the one exception — those use clear polystyrene to maximize visual contrast against our specialty black agar.)
Are these the same genetics as your liquid culture syringes and grow kits?
Yes. Every agar plate is grown from our master culture and 1st-generation isolated King Trumpet strain — the same genetics in our LC syringes and grow kits. Lab-tested, commercial-grade, and refined over multiple generations for vigor and yield.
How long will the plate stay viable?
An unopened, parafilm-sealed plate stored at 55–70°F in a dark place stays viable for 60–90 days. For longer storage, refrigerate at 35–40°F, where it can stay viable for 6–12 months. King Trumpet handles cold storage well and recovers quickly once brought back to room temperature.
Can I use this plate to make grain spawn directly?
Yes — that's one of the most common uses. Under a still-air box or laminar flow hood, cut a small wedge (about the size of a pencil eraser) from the colonized plate and drop it into a sterilized grain spawn bag or jar. King Trumpet typically colonizes grain in 10–14 days at room temperature — a bit slower than the other oysters.
How should I cook King Trumpet mushrooms?
The stems are the star. Slice them into thick rounds, score a crosshatch on each face, and sear in a hot pan with butter or oil for a scallop-style dish. You can also slice lengthwise and grill, roast at 425°F, or shred with a fork and pan-fry for a pulled-meat texture. King Trumpet holds its shape through almost any cooking method and stays firm rather than going soft.
What if my plate arrives contaminated or damaged?
We guarantee every plate ships in clean, fully colonized condition. If you receive a contaminated or damaged plate, contact us within 5 days of delivery with a photo and we'll replace it free of charge.
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