Knowledge Base — Plant Data Model

1. Plant record — schema

Each crop is one record. Fields:

2. Planting-window model (the "when to plant, per zone" answer)

The US spans zones 3–11 — a fixed calendar is useless. Every window is stored relative to an anchor the Twin knows per user, then resolved to real dates against the user's frost dates / zone (FR-1) and fed to the Calendar (FR-11):

• Anchor: last_frost (spring) · first_frost (fall) · soil_temp (e.g. corn needs ≥60 °F) · daylength (onions).
• Offset: signed weeks from the anchor, min/max (a window, not a date).
• Mode: direct (sow in place) or indoor (start inside, transplant later).

Examples: peas = {anchor:last_frost, offset:-6..-4, direct} · tomato = {anchor:last_frost, offset:-7..-6, indoor} then transplant {anchor:last_frost, offset:+1..+2} · garlic = {anchor:first_frost, offset:-4..-2, direct} (fall-plant) · spinach = spring {-6..-4} and fall {anchor:first_frost, offset:-8..-6}.

This model is the US localization: Seymour's "sow in March" becomes "sow 4–6 weeks before your last frost," correct in Maine and Georgia alike. It also carries heat caveats he underweights (bolting, poor fruit-set in extreme heat) as us_adaptation_note.

3. Rotation model — "how they follow each other"

3.1 Seymour's 4-year garden rotation (his sequence, our words)

Manure & plant ① Potatoes → lime, then ② Legumes (peas, beans) → set out ③ Brassicas after the legumes → ④ Mixed (onions, tomatoes, lettuce, sweet corn, cucurbits) → ⑤ Roots (carrots, parsnips, beet, celery) → back to potatoes. His disease/soil logic (all functional facts we keep): - ≥3-year gap between brassicas (prevents club-root build-up). Radish, turnip & swede are brassicas — rotate with them. - Gap between potato crops (eelworm). - Potatoes dislike fresh lime (causes scab); peas/beans like lime; brassicas like limed ground once settled; roots dislike freshly manured ground.

3.2 Modern family-based refinement (our addition — the "not the ceiling")

Group by botanical family and keep a 3–4 year gap per family — cleaner than Seymour's crop-name scheme, and it fixes one thing he glosses: tomatoes/peppers/eggplant are nightshades like potatoes and should rotate with them (shared blight/verticillium), not sit in "mixed." Groups → Beds trail colors:

Self-Collision (FR-15) fires when a new planting would cross a recent same-family trail inside its gap window; legume gold trails deposit nitrogen (FR-16). The sequence a user is nudged toward: legumes → nitrogen-hungry brassicas/leafy → fruiting nightshades/cucurbits → light-feeding roots/alliums → back to legumes.

4. Catalog (generated from plants.json)

155 crops — 80 vegetable, 31 herb, 30 fruit, 7 grain, 7 cover. 40 carry per-cultivar depth (115 cultivars). Download the machine-readable data: plants.json. All values are first-pass — verify against Cooperative Extension / NCHFP before shipping (NFR-16).

Window key: weeks relative to frost — LF=last frost, FF=first frost, negative = before. Resolved per user's zone (FR-1). Spacing: in-row inches (square-foot plants/ft²). Hard: H=hardy · ½=half-hardy · T=tender.

4.1 Vegetables

4.2 Herbs

4.3 Fruit & berries (Orchard engine, §4.8)

4.4 Grains & cover crops

4.5 Per-crop cultivation detail

Every record in plants.json carries five cultivation fields — soil & climate · propagation · care · pests & diseases · harvesting & storing — plus, where a crop needs it, an extra_sections list of crop-specific one-offs (176 across 97 crops: e.g. tomato Planting out/Stopping, potato Chitting/Earthing up, onion Curing, rhubarb Forcing, fruit Pruning/Grafting). Derived clean-room from Seymour (both editions) + modern US practice. Three worked examples below; the one-off set is first-pass and gets a per-plant cross-check against the book at the NFR-16 content-verification gate.

Tomato
- Soil & climate: Full sun; moderate, even moisture water. Soil: rich, well-drained soil, pH 6.0–6.8. Climate: warm-season; frost kills it. - Propagation: Start indoors 6–4 weeks before the last frost; transplant out 1–2 weeks after the last frost once soil is ≥60°F; space 24 in apart (0.5/sq ft). - Care while growing: Stake or cage; prune suckers on indeterminates; mulch and water evenly to prevent blossom-end rot and cracking. - Pests & diseases: Watch for late blight, early blight, hornworm, blossom end rot. Rotate on a 3–4 year family cycle, encourage beneficials, and remove affected material. - Harvesting & storing: Pick as they color up. Water-bath can ONLY with added acid (lemon/citric), or freeze/dry; green tomatoes ripen indoors. - Planting out (crop-specific one-off): Set plants deep (lowest leaves near the soil) so the buried stem roots; drive a tall stake in first when transplanting so you don't spear the roots later. - Stopping & side-shooting (crop-specific one-off): On indeterminate (cordon) types, pinch out the side-shoots in each leaf axil and 'stop' the plant (remove the tip) a few leaves above the top truss. Determinate/bush types are left alone. - Ring culture (crop-specific one-off): Under glass, grow in bottomless pots of compost stood on gravel — water the aggregate to feed the roots and the pot to feed the plant, which curbs soil disease. - Grow bags (crop-specific one-off): Where there's no bed, plant two or three to a grow bag; watch watering, as bags dry out fast and can't be over-filled. - Keeping plants low (crop-specific one-off): In a small plot, plant close, stop each plant after one truss, and allow no side-shoots — ruthless, but it can give more early ripe fruit. - Ripening (crop-specific one-off): At season's end pick sound green fruit to ripen indoors, or lift and hang the whole plant under cover.

Potato
- Soil & climate: Full sun; moderate even water. Soil: loose, slightly acid, pH 5.0–6.5 — NEVER add fresh lime (causes scab). Climate: cool-season; frost-tender tops. - Propagation: Plant tubers 2–0 weeks before the last frost; space 12 in apart. - Care while growing: Hill soil over stems as they grow (blocks light/greening); mulch; even water. Rotate with ALL nightshades. - Pests & diseases: Watch for colorado potato beetle, late blight, scab, eelworm. Rotate on a 3–4 year family cycle, encourage beneficials, and remove affected material. - Harvesting & storing: New potatoes at flowering; main crop after tops die. Cure 1–2 weeks in the dark, then root-cellar cool, dark, humid. - Chitting (crop-specific one-off): For early crops, 'chit' seed potatoes: stand them eyes-up in a cool, light place 4–6 weeks before planting to grow short, sturdy green sprouts. - Earthing up (crop-specific one-off): Draw soil up over the stems in stages as they grow — this blanks tubers from light (green tubers are toxic), suppresses weeds, and lifts yield. - Growing in containers (crop-specific one-off): No dig-space? Grow in bins, sacks, or on top of compost, adding material as the haulm grows, then tip out to harvest. - Blight management (crop-specific one-off): In warm, wet spells watch for late blight; remove the haulm at the first sign so spores don't wash down to the tubers. - Storing (clamping) (crop-specific one-off): Cure lifted tubers a week or two in the dark, then store in a clamp or in the dark in a cool, frost-free, humid place.

Blueberry
- Soil & climate: Full sun; even moisture. Soil: MUST be acidic, pH 4.5–5.5 (amend with peat/elemental sulfur; mulch with pine). Climate: hardy (highbush) to warm (rabbiteye). - Propagation: Plant 2+ dormant/potted varieties; space 48 in; do not let dry out. - Care while growing: Mulch deeply; keep acidic; plant 2+ varieties for pollination; net against birds. - Pests & diseases: Generally trouble-free once established. Keep plants healthy, space for airflow, and remove affected material. - Harvesting & storing: First real crop around year 3. Store by: use fresh, can, freeze, dry. - Planting (crop-specific one-off): Plant 2+ varieties for cross-pollination in acidic soil (pH 4.5–5.5), mulched with pine — never let the roots dry out. - Pruning (crop-specific one-off): From year 3–4, cut out the oldest canes each winter to keep young, productive wood coming.

5. Status & what's next (for KB epics)

• ✅ Comprehensive catalog — 155 crops (vegetables, herbs, fruit & berries, grains, cover crops), US-localized, from Seymour's roster (both editions) + common US crops.
• ✅ Per-cultivar depth — 115 named cultivars across 40 major crops.
• ✅ Full cultivation detail on every record — soil/climate, propagation, care, pests & diseases, harvesting & storing (cultivation field).
• ✅ Machine-readable — plants.json (schema §1 as the contract, frost-relative windows, rotation groups, fruit fields). This is what the rules engine (FR-19) loads.
• ⏳ Verification pass (required before ship, NFR-16): every planting window, spacing, DTM, chill-hour, and pest/food-safety figure is first-pass and must be checked against Cooperative Extension / NCHFP.
• ⏳ Next depth: cultivar-level cultivation nuance, evidence-based companion data (FR-18), regional layers (humidity/disease pressure), and turning varieties into per-variety DTM/resistance data.