🐛✗ Tested and false“Sclerotinia's resting bodies break down in the soil within a season or two, so ground where it appeared is fine to replant straight away”
The hard black sclerotia the fungus survives as are built for the long haul, not a single winter. Scottish field monitoring on oilseed rape puts survival at up to eight years, and a Kentucky vegetable-disease fact sheet gives a working figure of up to five years for the same structures in a vegetable setting. Either figure rules out treating a bed as clear again after one clean season.
Our read The two figures come from different crop systems (field-scale oilseed rape versus vegetable plots) and land in different places, five years against eight, which says more about how hard this is to pin down precisely than about which number is right. Both agree the sclerotia outlast any single crop cycle by years, which is the part that actually changes what a gardener should do.
What to do: Treat any bed where sclerotinia has shown up as carrying risk for several years, not one season. Plan replanting of susceptible crops around that timescale rather than the calendar.
In Scotland: The eight-year figure comes from Scottish government monitoring of the same fungus in commercial oilseed rape fields, so it reflects Scottish soil and climate conditions directly, even though the crop being monitored differs from a vegetable bed.
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“If sclerotinia's white mould is only on part of a vegetable, you can cut that bit off and eat the rest”
Iowa State University's extension guidance on white mould in vegetables states plainly that fruits and pods infected by the fungus are unmarketable, unsalvageable and inedible, without qualifying that by how much of the piece is affected or whether the mouldy part has been cut away.
What to do: Discard vegetables and pods with visible sclerotinia infection rather than trimming and eating the unaffected-looking remainder.
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“Sclerotinia is really an oilseed rape and farm-crop problem, home vegetable gardens with a normal mixed planting are unlikely to see it”
A Kentucky university extension fact sheet aimed specifically at vegetable growers lists more than 150 plant species as hosts, and its own vegetable table names beans, beets, all the cole crops, lettuce, okra, onion and garlic, parsnip, peas, peppers, potatoes, radish, spinach, squash and tomatoes among them. RHS separately describes it as affecting a very wide range of plants, listing lettuce, beans, celery, cucumbers, tomatoes and peas by name alongside ornamentals such as Delphinium and Dahlia.
Our read A mixed vegetable garden growing several of those crops together is not the low-risk setting the claim implies; if anything the wide host range means a mixed bed offers the fungus more potential hosts in one place, not fewer.
What to do: Don't assume a home vegetable plot is safe from sclerotinia just because it isn't a commercial oilseed rape field. Watch any of the wide range of susceptible crops, particularly legumes, brassicas, lettuce and root vegetables, for the disease's characteristic white cottony growth during wet weather.
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- University of Kentucky Cooperative Extension, Sclerotinia Diseases of Vegetable Crops (PPFS-VG-29)Sclerotinia diseases have a host range of more than 150 plant species, including fruits, ornamentals, agronomic crops, weed species and a long list of common vegetables, herbs and cover crops set out in its own table.
- RHS, Sclerotinia diseaseThe fungus affects a very wide range of plants including vegetables such as lettuce, beans, celery, cucumbers, tomatoes and peas, as well as ornamentals.
“Rotating vegetables around the plot doesn't really protect against sclerotinia, since it attacks almost every vegetable anyway”
Rotation is a genuine, recommended part of managing this disease, but the fungus's host range makes it a weaker tool for sclerotinia than for most other soil-borne problems. A Kentucky extension fact sheet lists beans, beets, brassicas, lettuce, onion and garlic, parsnip, peas, peppers, potatoes, radish, spinach, squash, tomatoes and watermelon as all being hosts, which covers most of a typical vegetable garden. The same fact sheet's actual non-host rotation options are cereals and grasses (corn, wheat, barley, oats, sudan grass), not other vegetables.
Our read This is why the claim reads as neither fully busted nor fully true. Swapping which vegetable goes in a bed each year, tomatoes one year, beans the next, isn't real rotation against sclerotinia if both crops are hosts; the fungus doesn't care which host it gets. Genuine rotation for this disease means breaking the bed out into a non-host cover crop or cereal for several years, which is a bigger ask than the usual four-bed vegetable rotation most gardeners already run.
What to do: Don't rely on a standard vegetable rotation alone to clear sclerotinia risk from a bed. If a bed has had an outbreak, consider putting it down to a genuinely non-host cover crop such as oats or ryegrass for a season or more rather than just moving to a different vegetable.
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“Giving plants more space and better airflow around the base genuinely cuts the risk of sclerotinia taking hold”
Three separate extension and horticultural sources independently name spacing and airflow as a real control point for this disease. RHS notes that crowded plants let the fungus reach a neighbouring plant across a shorter distance at soil level, Iowa State recommends sufficient row spacing and pruning to maintain airflow through the canopy, and Kentucky's extension fact sheet lists proper plant spacing for improved air flow as a standard cultural practice.
What to do: Space susceptible crops to the wider end of their recommended spacing and avoid letting foliage crowd together at the base, particularly through wet spells in early summer.
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