Editorial Method

Source hierarchy

Primary public datasets and university Extension publications are preferred. Regional calendar dates are not copied into a national rule unless the underlying guidance supports a frost-relative interpretation.

Rule review

Each plant rule records method, season, depth, spacing, maturity range, source links, and review date. Calculations preserve ranges and expose the selected probability instead of presenting one guaranteed date.

Publication boundary

Unsupported forecasts, treatment advice, pesticide instructions, and universal packet or planting claims are out of scope. Material changes require a test, source review, and a new reviewed date.