White Ball Mushroom in Yard: Puffball or Amanita Egg?

A white ball in the grass with no visible cap, stem or gills is one of three things, and a single vertical cut tells you which.

• True puffball. The cross-section is uniform white all the way through, with a texture usually described as marshmallow-like. The Missouri Department of Conservation describes the giant puffball as pure white inside when fresh and young, turning yellowish green with age, and says explicitly to cut any puffball from top to bottom to confirm it is pure white inside with no sign of a cap or stem.
• Amanita egg. A young Amanita still wrapped in its universal veil looks like a small puffball from outside. Cut lengthwise, it shows the outline of a developing mushroom — a cap, a stem and the beginnings of gills. This is the reason the cut exists as a standard check, because in the egg stage it is impossible to tell which Amanita species you are looking at, and the genus includes the death cap and the destroying angels.
• Earthball, Scleroderma. The outer skin is thick, tough and scaly rather than smooth, and the interior turns purple-black from the centre outward very early. NC State's plant toolbox and other references describe the inside as never pure white, usually dark purple to black with a pale rim. Scleroderma species are toxic and cause nausea, vomiting, diarrhoea and abdominal pain.

This site does not tell you any of these is safe to eat. The cut is a hazard check, not a permission slip.

A white ball the size of a grapefruit or a soccer ball is usually the giant puffball, Calvatia gigantea. The Missouri Department of Conservation describes a round fruiting body, white outside, pure white and marshmallow-like inside when young and yellowish green with age, a smooth soft outer surface that cracks irregularly, a root-like attachment at the base, and a greenish brown spore print. It grows in open pastures, woods and lawns from May to October. Reference sources put typical dimensions at roughly 4 to 19 inches wide and high, with exceptional specimens reaching about 80 cm and weighing several kilograms.

Giant puffballs are conspicuous because they appear overnight. There is no cap and no gills at any stage. When the flesh inside stops being white and starts turning yellow, olive or brown, the mushroom is converting to spore powder, and a mature one releases a brown cloud when kicked.

Two completely different things in a lawn look like small white eggs.

Amanita buttons. Every Amanita begins life wrapped in a universal veil. At that stage it is a smooth white or off-white ball sitting on or just under the soil surface, often near a tree. As it expands, the veil tears: the top breaks into warts or patches on the cap, and the bottom stays as the cup-like volva around the stem base. Because the egg stage hides every species-level feature, identification is impossible until it opens, and the genus contains species whose amatoxins destroy liver tissue. Poison Control notes that the most toxic mushrooms may be growing in your own yard and that a few bites can cause fatal liver damage.

Stinkhorn eggs. NC State Extension describes stinkhorns emerging from egg-like structures in mulch and damp decomposing material, and calls the immature stage dragon-egg-like. Cut one and you find a gelatinous layer around a compressed, folded stalk, not solid white flesh and not a gilled mushroom outline. Within hours the egg ruptures and the smell arrives. See stinkhorn mushroom in yard.

If children play in the yard, remove white eggs on sight, gloved and bagged. You cannot tell from the outside which of the three they are.

Scleroderma species are commonly called pigskin poison puffballs, and they are the reason puffballs cannot be treated as a uniformly harmless group.

How they differ from true puffballs:

• Skin. Thick, tough and leathery with a warty or scaly surface, compared with the thin smooth skin of a true puffball.
• Interior. Firm and quickly purple-black or marbled dark, not uniform white. References describe the interior as never pure white and often showing pale vein-like lines through the dark flesh.
• Opening. True puffballs of the Lycoperdon group develop a pore at the top; earthballs tend to crack open irregularly instead.

Scleroderma is listed by the North American Mycological Association among the genera that can be lethal to dogs, alongside Amanita, Inocybe and Clitocybe. That makes an earthball in a yard with a digging dog a practical problem, not just an identification curiosity.

• Photograph it whole first, then cut and photograph the cross-section. Photograph it with the app and it identifies it. The cut face is the single most informative image you can take of a ball-shaped fungus.
• Remove it before it matures. A giant puffball that turns to spore powder makes a mess and a young one is easier for a child to mistake for a ball.
• Gloves, bag, household bin.
• Check the same area for more. Balls in a line or arc suggest a fairy ring colony; Illinois Extension notes puffballs may emerge along a ring edge after rainfall.
• Never let a cut test become a taste test. Poison Control's position is that only mushroom identification experts can distinguish poisonous from harmless species and that eating any amount of any wild mushroom can be very dangerous.
• If a child or pet has eaten part of one, call 1-800-222-1222, or your vet and ASPCA Animal Poison Control at (888) 426-4435, and keep the remaining half in a paper bag in the fridge.

Once the cut shows a uniform white interior, size and surface narrow down the puffball:

• Common puffball, Lycoperdon perlatum. Small: 1.5 to 6 cm wide and 3 to 10 cm tall, off-white, with short spiny 'jewels' that rub off and leave a net pattern. When mature, a hole opens at the top and the white inside turns yellowish, then to olive-green spore powder. Fields, gardens and grassy clearings, sometimes in fairy rings (Wikipedia).
• Purple-spored puffball, Calvatia cyathiformis. Medium: 5 to 20 cm, round at first and later pear- or top-shaped; the inside goes from white to yellow to dull purple or purple-brown. Grasslands, prairies and grazed paddocks in North America and Australia (Wikipedia).
• Giant puffball, Calvatia gigantea. Large: 8 to 20 inches across, occasionally weighing more than 25 pounds; May to October, singly or in groups in pastures, woods and lawns (Missouri Department of Conservation).
• Bovista. Small, with a very thin papery skin; old ones often tumble around in the wind (Practical Self Reliance).

If the inside is dark and firm rather than white, it is an earthball, not a puffball; see the section above.

To the lawn, no: the Missouri Department of Conservation describes the giant puffball as a saprobic fungus that breaks down dead organic matter and returns nutrients to the soil. It is not attacking the grass.

The spores are a different matter. The same source cites an estimate of about seven trillion spores in a single 15-inch puffball. Wikipedia describes lycoperdonosis, a rare lung disease caused by inhaling large amounts of spores from mature puffballs. It starts with cold-like symptoms within hours and can progress to nausea, a fast heartbeat and difficulty breathing. Documented cases include teenagers hospitalised after inhaling spores at parties, one patient who needed life support for about four weeks, and dogs that played or dug near puffballs. Wikipedia notes it is rare, probably because it takes deliberate inhalation to reach such high concentrations.

In a family yard that means:

• Remove puffballs while they are still white inside, before they turn to powder.
• Do not let children stamp on or kick mature puffballs near their faces, or play at blowing the 'smoke'.
• Keep digging dogs away from patches of mature puffballs.
• Anyone with breathing trouble after spore exposure should see a doctor and mention the puffballs.

Often, yes. The writer of Creative Sustenance reports finding a few softball-sized puffballs in the same yard every year and notes that it is common to find several growing near one another. Wikipedia and Practical Self Reliance both note that grassland puffballs can form fairy rings. Because puffballs feed on dead organic matter in the soil, the fungus lives on underground after you remove the balls; removal stops the spores, not the next crop.

There is no spray for them. University of Illinois Extension states that there are no recommended fungicides for these species, and the University of California IPM program says fairy rings are managed faster and better with cultural practices than with a fungicide. What the extension services recommend:

• Break or mow them off when they first appear (Illinois Extension), before they mature and release spores.
• Dig up buried organic matter where many come up in one spot, such as old roots or construction lumber (Illinois Extension; UC IPM).
• Aerate to break through dense fungal mats under the surface (Illinois Extension).
• For fairy rings, UC IPM suggests aerating or applying nitrogen fertiliser at 1 pound per 1,000 square feet to speed up the breakdown of the organic matter.

Expect them back. UC IPM notes that removing mushrooms does not kill the underground mycelium, so picking stops spores, not the next crop.

Not every white, puffy thing in a yard is a fungus ball.

• Slime mould. Dog vomit slime mould, Fuligo septica, starts as a white to yellow-grey spongy mass 2.5 to 20 cm across on mulch or lawns after heavy rain or watering, then darkens (Wikipedia). It is not a fungus, does not harm plants and disappears as the weather dries, but its spores can trigger asthma and allergic rhinitis in susceptible people. UC IPM describes slime moulds in lawns as a gooey mass that can look like vomit.
• Stinkhorn eggs. White or pale balls half-buried in mulch, attached by white cords, with a jelly layer inside; see stinkhorn mushroom in yard.
• Earthballs. Firm, thick-skinned and dark inside; see poison puffball mushroom.

Mostly good for the soil. University of Illinois Extension describes lawn puffballs and mushrooms as fungi breaking down once-living material and recycling it into the soil, a process that releases nitrogen. The downside it notes is that dense fungal growth can stop water soaking in and cause local browning. The practical problems are the spore clouds from mature balls and the chance that a child or dog eats a look-alike, both covered above.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat. If you find an error, tell us and we will correct it.