Data sources

veggie.farm is moving from a library of gardening information toward explainable garden decisions. That means every recommendation should show what came from a source, what was modeled, what the gardener entered, and what veggie.farm calculated.

Four evidence layers

Reference data

Taxonomy, plant characteristics, hardiness, soil maps, and climate normals. These change slowly and can be versioned.

Horticultural guidance

Germination, planting, spacing, maturity, tolerance, and care facts, ideally supported by Cooperative Extension evidence.

Environmental conditions

Forecasts, recent rain, estimated soil temperature, soil moisture, and evapotranspiration. These need timestamps and caching.

Garden observations

The gardener's beds, amendments, microclimates, planting dates, harvests, problems, and notes. These should never be overwritten by public estimates.

Current production data

The current site now uses four deliberately different collections:

The Garden Today tool keeps those roles visible. Regional Extension dates are presented as regional benchmarks, not universal cutoffs. Soil-temperature estimates still come from the cultivar catalog and should be checked against the seed packet. If a user requests a forecast, an NWS near-freeze signal can reduce tender-crop recommendations.

The location lookup is explicit. The browser rounds coordinates to 0.001°, sends them directly to NWS, and does not retain them in the forecast record or browser storage. NWS forecast data is cached only in page memory for 20 minutes.

My Garden stores frost dates, explicit soil overrides, and dated observations only in the gardener's browser. These user observations remain a distinct evidence class; they do not overwrite public or modeled source values.

Provider status

Provider Role Acquisition Status
Cooperative Extension collection Reviewed crop evidence from UMaine, UMN, UMD, USU, and Penn State Seven versioned factual snapshots Active: 165 normalized facts; all 23 core crops
National Weather Service Current U.S. forecast conditions Opt-in live query; memory cache Active
World Flora Online Canonical taxonomic names and synonyms Versioned snapshot Planned
USDA PLANTS U.S. plant characteristics and distribution Snapshot or supported export Planned
USDA hardiness map Perennial winter-survival context Versioned spatial snapshot Planned
NOAA climate normals Frost probabilities and long-term growing-season context Versioned snapshot Next priority
NRCS Soil Data Access Location-specific mapped soil estimates Serverless query and cache Next priority
Open-Meteo Modeled soil temperature, moisture, and ET₀ Licensed query or self-hosted Evaluated; free endpoint deferred

Open-Meteo is not silently used: its free API is restricted to non-commercial use, and its troubleshooting logs may retain coordinates for up to 90 days. That provider can be reconsidered with an appropriate paid deployment or self-hosting. Any future modeled soil value will be labeled as a model estimate rather than a physical sensor reading.

Evidence record contract

Each normalized horticultural fact has a stable evidence ID, crop key, trait, typed value and unit, method where relevant, geographic applicability, immutable source snapshot, source URL, retrieval date, review status, and confidence class. Conflicting future sources can therefore coexist; a derived rule can choose among them without rewriting the source facts.

Product rule

The calculation engine returns structured facts and reason codes first. Friendly explanations come afterward. A language model may help phrase an explanation, but it must not invent frost dates, soil values, crop thresholds, weather observations, or pesticide guidance.

For the implementation boundary and next steps, see the project documentation in docs/data-architecture-current.md and docs/data-architecture-target.md.