Methodology & Data Sources

Every planting recommendation, companion pair, spacing value, and zone range in JoeBees is derived from peer-reviewed extension research and established horticultural references. This page documents exactly which sources were used and how the data is structured.

How the plant database works

Each of the 79 plants in the database carries a structured record with the following verified fields:

  • Spacing (inches) — follows Mel Bartholomew's Square Foot Gardening convention: 3, 4, 6, 9, 12, 18, 24, or 36 in., depending on mature plant size.
  • USDA hardiness zones — the inclusive zone range in which the plant reliably grows, from the 2023 USDA PHZM.
  • Sun requirement — full sun (6+ hrs direct), part sun (3–6 hrs), part shade, or shade.
  • Planting months — months 1–12 when the plant should be sown or transplanted in the Northern Hemisphere, based on Almanac and extension service data.
  • Harvest months — expected harvest window.
  • Days to maturity — from transplant or direct sow to first harvest, per Almanac and seed-catalog data.
  • Companions — plant IDs that produce a documented, mechanistic benefit when planted nearby. Vague anecdotal pairings are excluded.
  • Antagonists — plant IDs with documented inhibitory effects (allelopathy, shared pests, root competition).
  • Soil type & pH — preferred growing medium and pH band, cross-referenced with extension soil guides.

Companion and antagonist standards

A companion pair is only included when a specific, documented mechanism exists — not because of general folklore. Examples of accepted mechanisms:

  • Volatile aromatic compounds that repel specific pests (e.g., basil and tomato hornworm)
  • Root exudates with documented nematode-suppression (e.g., French marigold alpha-terthienyl)
  • Nitrogen fixation by legume root nodules benefiting adjacent heavy feeders
  • Physical structure providing shade, wind shelter, or climbing support
  • Trap-cropping that draws pest species away from the primary crop

An antagonist pair is included when one or more of these is documented:

  • Allelopathic root or foliar exudates that suppress germination or growth (e.g., fennel)
  • Shared primary pest or pathogen that amplifies infestation risk (e.g., tomato and potato sharing blight)
  • Inhibition of nitrogen-fixation symbiosis by allium root exudates near legume roots
  • Documented nutrient competition producing measurable yield reduction

Spacing and Square Foot Gardening

The planner uses Mel Bartholomew's Square Foot Gardening (SFG) spacing convention. Each cell in the grid represents one 12-inch square. The number of plants per cell is calculated as:

plants_per_cell = floor(12 / spacing_inches)²

Plants with a spacing greater than 12 inches span multiple cells. Their footprint is calculated as ceil(spacing_inches / 12) cells per side. No two plants' footprints may overlap on the canvas.

This model matches the SFG tables published in All New Square Foot Gardening (3rd ed., Cool Springs Press).

AI layout generation

When you describe a planting goal, JoeBees sends your bed dimensions, sun/soil/pH/zone conditions, and a filtered view of the plant catalog to Claude (Anthropic) via a server-side API route. The AI is given explicit rules derived from the companion and antagonist data above — it cannot place antagonists within 2 cells of each other, and all plant footprints must respect SFG spacing.

The returned layout is then validated server-side: unknown plant IDs are filtered out, coordinates are clamped to the bed dimensions, and obvious antagonist conflicts are flagged for the user to review. The AI does not override the database — it works within it.

References

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