Do not plant legumes in ground that held legumes within 3 years; the root rots build where they repeat, and the worst of them outlast any garden rotation.
Promising · costly if ignored → warn
How it works
Bean and pea root rots (Fusarium solani, Rhizoctonia, Pythium, Aphanomyces) and white mold (Sclerotinia sclerotiorum) survive in soil as spores and sclerotia and build where legumes follow legumes; a three-year break holds the common ones down. Fusarium needs longer, and Aphanomyces oospores and white mold's sclerotia persist for many years, so rotation reduces but cannot clear them.
What to do about it
Plant legumes in different ground, or wait until 3 years have passed since this ground last held them. Where root rot has shown, make it longer, and keep the ground draining freely: every one of these rots is worse in wet soil.
How much it matters: Cornell's rotation table: beans root rots 3 years, white mold 3, anthracnose 2; peas root rots 3-4, Fusarium wilt 4-5. UMN: more than 3 years away from legumes, and more than 6 for Fusarium. UConn: 7 years for white mold. NDSU: pulses in close rotations every 2-3 years are at greatest risk.
The evidence
Evidence: confirmed against 4 sources in the research-based literature.
the 4 sources
Cornell Vegetables, 'Do Rotations Matter within Disease Management Programs?', vegetables.cornell.edu/pest-management/disease-factsheets/do-rotations-matter-within-disease-management-programs (fetched in-container 2026-09-02; read by the maintainer 2026-09-02): its rotation table gives beans root rots 3 years, white mold (Sclerotinia) 3 years, anthracnose 2 years; peas root rots 3-4 years, Fusarium wilt 4-5 years.
UMN Extension, Fruit and Vegetable News, 'Crop planning deep dive: Mind your Peas and Beans' (2021), blog-fruit-vegetable-ipm.extension.umn.edu/2021/04/2021-consideration-minding-your-peas.html (fetched in-container 2026-09-02; read by the maintainer 2026-09-02): 'Rotate away from legumes for more than 3 years'; 'More than 6 years is needed for some diseases (Fusarium, some damping off pathogens).'
UConn IPM, 'Molds and Mildews of Beans in Connecticut', ipm.cahnr.uconn.edu/molds-and-mildews-of-beans-in-connecticut (fetched in-container 2026-09-02; read by the maintainer 2026-09-02): white mold - 'Rotate away from susceptible crops for 7 years', it affects beans and 'practically all vegetable crops'; downy mildew - 'Rotate with other crops for 2 years.'
NDSU Agriculture, 'Field Pea and Lentil Root Rot Risk, Diagnosis and Resources', ndsu.edu/agriculture/ag-hub/field-pea-and-lentil-root-rot-risk-diagnosis-and-resources (fetched in-container 2026-09-02; read by the maintainer 2026-09-02): 'Fields with a long history of pulses in close rotations (every 2-3 years) are at greatest risk'; 'Chickpea, soybean, and faba bean are not susceptible to Aphanomyces euteiches and thus can be included in a rotation with pea and lentil to break up the disease cycle.'
Plants this fires on
- Common Bean
- Cowpea
- Crimson Clover
- Edamame
- False Indigo Bush
- Fava Bean
- Hairy Vetch
- Lima Bean
- Pea
- Runner Bean
- White Clover
- Wild Lupine
Change history
Every change to this rule is one commit. This is what the project's version history records — the date and the reason — not a summary of it.
- rules: another rule here - legumes rotate on a 3-year interval (verified), family-wide by the maintainer's ruling (O133 step 7, family 4)
Cite this page
Milpa Gardens. "Do not plant legumes in ground that held legumes within 3 years; the root rots build where they repeat, and the worst of them outlast any garden rotation." Evidence grade: Promising. https://milpa.garden/rules/do-not-plant-legumes-ground-that-held/
A garden-planning corpus: every claim states its evidence grade and links its sources on the page. Cite it with the grade, and add the date you read it.