Tomatoes, peppers and eggplant set little fruit while the nights stay cool.
As recorded: Tomato and eggplant set little fruit while nights stay below about 13 C (55 F), and pepper below about 15.5 C (60 F).
Promising A person has checked it against its sources. If you skip this, you lose real yield. The planner warns you.
How it works
Low temperatures cut the pollen's viability and slow the growth of the pollen tube, so the flowers drop without setting fruit.
What to do about it
Time the planting so it flowers in months whose nights are warmer than that, and grow a cool-season crop through the coldest months.
The evidence
Evidence: checked against 4 sources in the research-based literature.
The 4 sources
Less than 13°C (55°F)
Night temperatures below 60° F. and above 75° F. or day temperatures above 95° F. can cause pepper flowers and small fruits to drop.
This occurs when nighttime temperatures fall below 55°F or stay above 70°F, or daytime temperatures rise above 90°F for extended periods.
Conversely, nighttime temperatures below 55 degrees F also promotes blossom drop.
Where this rule stops
It reads each month's normal low, which stands in for the nights, so a cold snap in a mild month is not seen. Ontario's table states that its numbers are daily highs and lows in the field, the measure the normal lows are made of.
Plants it applies to · 3
How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- Added to the rules
More ways Milpa can help
When do I plant? · What grows well together? · Plan my garden · What can I plant now? · Something wrong in the garden? · Keep a garden diary · Heard a tip?
Cite this page
Milpa Gardens. “Tomatoes, peppers and eggplant set little fruit while the nights stay cool.” Evidence grade: Promising. https://milpa.garden/rules/tomato-eggplant-set-little-fruit-while-nights/
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.
Report a problem with this claim
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.