# Method

This edition joins 20 crop groups across five extension services, read on 26 October 2026 UTC. The 28 attributes preserve each source’s units, plant counts, named cultivars and type of advice. A second check compared all 560 joined cells with the selected sources; it was automated, and review by a horticulture specialist is pending. It is a comparison of published guidance, not a growing trial or a set of universal minimums.

## Sources and matching

The selected pages are listed in source-ledger.json. Their displayed dates are distinct from the observation date; Illinois shows no publication date. Every cell in the canonical index.json carries its source URL, observation time, table/paragraph locator, source crop label, match scope and conditions. CSV repeats those references beside each value.

Crop names are joined only through the stated crop or an explicitly identified broader group. Generic tomatoes do not become a cherry/patio recommendation. Maryland’s cherry row and UC’s cherry row cover only that subset of the combined cherry/patio ledger row. Wisconsin’s kale mention does not place it into the small-plant volume group. Maryland’s full cool-season label includes Asian greens; bok choy remains unjoined because that light passage does not name it. Maryland’s compact-variety caveat remains attached to the vegetable-volume conditions. Parsley retains both the large-herb volume context and its separate Salad Table/Salad Box mention. Null means the selected table or named group did not state that field; it does not describe all guidance published by that organization.

## Units and comparisons

The sole numeric normalization is explicit volume: one gallon equals four quarts or eight pints, using the U.S. liquid-unit convention. A gallon equivalent is an arithmetic description of a quoted unit, not measured container capacity. No liters are added. No volume is inferred from diameter, container depth, soil depth, spacing or plant count. Illinois volumes remain per listed container; they are never divided by its plant count. UC’s 2–5-gallon alternatives remain ranges and are not relabelled minima.

The difference flag compares stated numbers/ranges while retaining source conditions. It does not choose a winner, establish an agronomic contradiction or imply that different cultivars and densities are interchangeable. One volume source alone produces a null comparison. Internal differences remain visible: NC State’s prose potting-mix depth and table container depth are separate; UC’s light paragraph and final sun labels are separate. Bok choy’s printed 20-inch depth is retained without an invented correction.

## Practice and updates

The compilation records attributed facts and original comparison fields, links to the sources and does not reproduce their prose or images. Re-read the five selected pages when updating an edition, re-check each joined cell against its selected source, and record changed units, crop scope or conditions before replacing a value. This edition makes no claim about yields, weather, planting dates, structural suitability or unlisted cultivars.

JSON is canonical. CSV text beginning with a spreadsheet formula trigger is prefixed with an apostrophe. An empty CSV value corresponds to JSON null. Source facts are distinguished from the derived comparison fields. The observation data and original compilation are licensed CC BY 4.0; see LICENSE.txt. hashes.txt covers the files in this data directory except itself.