An insect-pollinated crop depends on an insect to move pollen between its flowers
An insect-pollinated crop depends on an insect to move pollen between its flowers; no arrangement of plants substitutes for one.
Well established A person has checked it against its sources. If you skip this, it still grows, just less well. The planner suggests it.
How it works
A monoecious cucurbit bears pollen and ovules in separate flowers, so fertilization requires a vector to carry pollen between them. Neither wind nor self-fertility applies. Ovules that are not fertilized do not develop, and the fruit aborts or forms misshapen.
What to do about it
Nothing here can guarantee insects, and their absence cannot be diagnosed from a plant list. What you can change is whether anything in the garden is in flower while the crop is. Plants that feed insects near a fruiting crop are a reasonably supported suggestion. They are not a proven fix.
How much it matters: Not quantified by any source read. Clemson states the outcome categorically ("no fruit formation or either poorly formed fruit") without a rate, and no source read gives a visits-per-flower threshold or a yield curve. Deliberately left unquantified. No estimate is made.
The evidence
Evidence: checked against 4 sources in the research-based literature.
The 4 sources
Squash have separate male and female flowers on the same plant, and pollen must be transferred from the male flowers to the female flowers by bees.
An insect must move the pollen from the male flowers to the female flowers. Bees are common squash pollinators.
Pumpkins and squash are dependent upon insect pollination.
Summer squash flowers require insect pollination and are only open in the morning
Read next
- Why is my squash not setting fruit? Pollination for the home gardenerLots of flowers and no fruit is usually a pollination problem. How squash, cucumbers, corn, and the crops that need a partner get pollinated, and the short list of what you can do about it.
- Floating row covers: frost protection, pest exclusion, and the one ruleA lightweight fabric that buys you a few degrees of frost, keeps pests off physically, and warms the soil. There's one hard rule about when you have to take it off, or you'll get no fruit.
- Why won't my tomatoes set fruit? Heat, blossom drop, and the shade-cloth mistakeA tomato plant covered in flowers that drop without making fruit is usually being stopped by the temperature, and specifically by the night temperature. That's why the shade cloth everyone reaches for does nothing.
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
- Sources updated
- Added to the rules
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Cite this page
Milpa Gardens. “An insect-pollinated crop depends on an insect to move pollen between its flowers; no arrangement of plants substitutes for one.” Evidence grade: Well established. https://milpa.garden/rules/insect-pollinated-crop-depends-insect-move-pollen/
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.