Is this normal? What mycelium looks like on agar, young and old

Healthy mycelium on agar usually spreads outward from the piece that started the plate, with nothing else growing on it, but color and thickness vary by species, strain and medium, so compare it with an earlier plate of the same line (our reading). An older Penn State guide to button mushroom cultures says their traits on agar "vary considerably from strain to strain", and that "no method is available to determine the ultimate productivity of a culture on agar" (Penn State).

Below is what our plates looked like, not a species standard or a controlled comparison: age, dye, medium and the side photographed all vary. Ages run from label date to photo date, assuming the label date is the transfer date. Sources checked 6 November 2026.

Why does "normal" change from plate to plate?

Normal changes because one species' warning sign can be another's ordinary growth (our reading). That Penn State guide lists "fluffy, aerial mycelium or a color change such as browning or darkening of the mycelium" as abnormalities, but it's a button rule: a morel strain in one study grew "a dense, cottony aerial mycelium" (J Fungi).

Our stages guide uses "clean white mycelium" as the general picture; morel is why that needs a caveat.

What does morel mycelium look like on agar?

Morel mycelium on agar can look white or yellow, and the colony or the agar can turn brown; strain, medium and temperature all shift it (J Fungi).

One plate labelled morel was white and nearly full 4 days from its label date. A different plate was tan at 14 days, with a dark patch we haven't identified. Neither label names a species.

In a study of Chilean morels, within one species, one strain had "a faint yellow hue" and another "a diffusion of dark brown pigmentation into the agar", while M. importuna strains had "moderately cottony white mycelium". The brown strain also formed pigmented sclerotia, compact knots of mycelium; the white ones formed white sclerotia (J Fungi).

Brown doesn't have to mean fine (our reading): when that study changed nitrogen source or temperature, some strains slowed and browned (J Fungi). Browning with slower growth than earlier plates deserves a closer look (our reading); for a dark spot, use our mold check. We don't know why our plate was tan or whether it has sclerotia.

What does lion's mane look like on an agar plate?

Lion's mane on an agar plate is described as white, sparse and flat in one culture collection's listing; our two different plates looked thin and branching at about 8 days and cream and cottony at 78.

The first, from a label date we read as 7/9/25, shows thin starbursts around rounded pieces; backlighting likely makes them look dark. Thin at about 8 days is our observation: no source we found calls it typical. The second has a dark rectangle we read as a cut-out. We can't say what made it cream.

The collection's listing, for one strain on potato dextrose agar (PDA), says "curved and white hyphae, sparse and flat colonies" and separately lists growth at 25 to 28 °C for 7 to 10 days (BNCC). North Spore calls lion's mane "wispy and faint" in spawn, not agar (North Spore help center).

Lion's mane on agar grew 2.10 to 4.31 mm a day by strain in one study, on malt extract agar at 25 °C (Foods). See our lion's mane guide.

What does pink oyster mycelium look like on agar?

Pink oyster mycelium on agar is described as white at first, and the pink in our photo reads as dyed agar, not the mushroom (our reading).

The plate we read as pink oyster, 8 days from its label date, shows pale growth spreading unevenly from a chunk, with most of the plate bare.

One spawn seller's page, crediting a Stamets book, says "White at first", "eventually cottony with maturity, and aerial", and "Most strains soon develop strong pinkish tones, especially as the mycelium matures, at and around the sites of primordia formation" (JMP Mushroom).

In one small study, pink oyster reached full growth in 6 days on wheat bran agar ("Dense, cottony, vigorous"), 8 on PDA and 12 on yeast extract agar ("Sparse, weak growth") (Eco. Env. & Cons.). Medium changes speed, but that may not explain ours: by eye, it covered under half the dish at 8 days, behind even that slowest medium. We don't know its medium, strain or conditions, so no verdict (our reading). See our pink oyster guide.

How do you judge your own plate?

Look for growth spreading from your piece and nothing else on the agar, then compare earlier plates of the same line at the same age and medium (our advice). No earlier plate? Date and photograph this one as your baseline. Green or black spots, or growth that didn't start from your piece, go to our mold or mycelium check (our advice).

• Sectoring and transfers: agar guide.
• Clone plates: is it contaminated?
• Writing it down: grow log.

How do you track a plate in Hypha?

Track each plate in Hypha as its own Culture block, so earlier plates stay there to compare against: go to Grows → Blocks → + → New (or Transfer for a plate cut from one you already track), then choose stage Culture and container Agar Plate. Add Photo every few days (phone app only). Finish a dead plate rather than deleting it.

In the phone app, View Lineage → More options → View Family Photos shows your newest 50 photos across that strain's blocks. Open one, then More options → Compare Photos lines up any two, with their dates.

Download Hypha; the free plan holds 25 active blocks, and each plate counts until you archive it.

FAQ

How long does mycelium take to grow on agar?

Days to three weeks, by species and medium: our morel plate was nearly full at 4 days, the pink oyster study above took 6 to 12 days, and a lab guide SARE hosts allows 1 to 3 weeks for a tissue clone (SARE).

How long does mycelium last on agar?

Months in the fridge, though sources differ on how many; our agar guide compares them. North Spore says its pink oyster cultures "cannot be refrigerated" (North Spore help center).