Sunflower residue suppresses germination of some small-seeded species.
Promising A person has checked it against its sources. If you skip this, you lose real yield. The planner warns you.
How it works
Sunflower tissue and roots release allelochemicals that persist in the soil and inhibit the germination and early growth of sensitive plants. Small-seeded, direct-sown neighbors are the ones at risk. A small seed has little reserve to push through the inhibition, whereas a transplant is already past the germination window and largely escapes.
What to do about it
Keep small-seeded direct sowings out of last year's sunflower ground, or plant transplants there.
How much it matters: Modest, and it matters only for direct-sown neighbors.
The evidence
Evidence: checked against 1 source in the research-based literature.
The source
If a sensitive test plant is exposed to allelopathic compounds, its seed germination and seedling growth are reduced
Plants it applies to · 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
- How it works updated
- Advice on what to do added
- A person read the sources and confirmed it
- Added to the rules
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Cite this page
Milpa Gardens. “Sunflower residue suppresses germination of some small-seeded species.” Evidence grade: Promising. https://milpa.garden/rules/sunflower-residue-suppresses-germination-some-small-seeded/
A garden planner built on graded evidence. 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.
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How we grade evidence
- Well established
- The rule names its mechanism and is settled, by sources a person has read and checked or by plain arithmetic and geometry.
- Promising
- The mechanism is named and the literature backs it. A few questions are still open.
- A good hunch
- Plausible by its mechanism, but field studies are thin, so treat it as a lean.
- Contested
- The evidence points both ways, or no study has tested it, so the planner does not enforce it.
- Refuted
- The claim did not survive its sources. It is kept so the folklore can be answered.