Where no station or model reaches, 3+ seasons of your own frosts give rough dates
As recorded: Where no weather station or model answers for a plot, three or more seasons of its logged frost outcomes give it rough frost dates of its own.
A good hunch If you skip this, it still grows, just less well. The planner suggests it.
How it works
Each logged frost is a direct observation of when frost reached that ground. With no station or model to correct, the middle of those observations is the plot's only frost estimate, and because frost dates swing from year to year, a middle taken from a few seasons is rough.
The evidence
Evidence: checked against 3 sources in the research-based literature.
The 3 sources
To use the FriskS.xls application, input a minimum of 20 years of daily minimum temperature data into the Data worksheet. However, use more years of data if available.
In general, a station must have at least 10 “sufficiently complete” months for each month of the year for normals to be computed
Using a minimum of 30 years ensures that the statistics are solid.
Where this rule stops
Three seasons give a rough middle date; frost-date records are usually built from 10 to 30 years.
How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- A person read the sources and confirmed it
- Added to the rules
Cite this page
Milpa Gardens. "Where no station or model reaches, 3+ seasons of your own frosts give rough dates." Evidence grade: A good hunch. https://milpa.garden/rules/where-no-weather-station-model-answers-plot/
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.
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.