Do not plant alliums in ground that held alliums within 4 years
Do not plant alliums in ground that held alliums within 4 years, and know that the worst allium disease outlasts any rotation.
Promising A person has checked it against its sources. If you skip this, you lose real yield. The planner warns you.
How it works
Fusarium basal rot (Fusarium oxysporum f. sp. cepae) and pink root survive in soil as spores and on other plants' roots, and their inoculum builds where alliums repeat; a four-year break starves them. White rot (Sclerotium cepivorum) is allium-specific and its sclerotia stay viable 15 to 40 years, so rotation reduces but cannot clear it.
What to do about it
Plant alliums in different ground, or wait until 4 years have passed since this ground last held them. If white rot has ever shown here, treat this ground as lost to alliums and grow them elsewhere.
How much it matters: UMass: at least 4 years away from alliums for Fusarium basal rot; Colorado State: onions not more than once every five years, and a rotation under 4 years favors every soil-borne onion disease it covers. White rot: rotation alone does not control it (UMD: sclerotia survive 20-40 years; UMass: 15 years or more).
The evidence
Evidence: checked against 4 sources in the research-based literature.
The 4 sources
Do not plant onions more than once every five years in a field
Rotation alone will not control white rot because sclerotia can survive in the soil for 20-40 years
White rot survives in soil in the form of sclerotia, which are dense masses of fungal tissue. ... They may remain viable in soil for 15 years or more without allium hosts.
Plants it applies to · 6
Onions & garlic · 5, Flowers · 1
Flowers · 1
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How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- Sources updated
- Wording made clearer
- Added to the rules
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Cite this page
Milpa Gardens. “Do not plant alliums in ground that held alliums within 4 years, and know that the worst allium disease outlasts any rotation.” Evidence grade: Promising. https://milpa.garden/rules/do-not-plant-alliums-ground-that-held/
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