{
  "schemaVersion": 1,
  "slug": "lawn-seed-calculator",
  "category": "gardening",
  "kind": "implementation",
  "independentValidation": false,
  "implementationHash": "446ee1e03ba80394d8da24c68f9aa5e25ffdca357deb46313c618c0dc783a217",
  "provenance": "Generated from the calculation contract used by the published page. Publication is not external validation.",
  "sourceFiles": [
    "data/calculators/lawn-seed-calculator.json",
    "src/engine.js"
  ],
  "runtimeSource": "/sources/engine.txt",
  "runtimeHash": "5c888d8898afbdee36267bb9977829e1e2ac568f6677c8ee87469c139864645c",
  "scope": "The compute function records implemented equations, constants, lookup tables and custom rules. Inputs record defaults and allowed values; outputs record precision and units. Defaults are examples, not recommendations. General background references are not evidence for this specific algorithm.",
  "publishedFormula": {
    "formula": "seed_lb=L×W÷1000×r×p×(1+w÷100); bags=ceil(seed_lb÷5)",
    "vars": [
      [
        "L,W",
        "lawn dimensions (ft)"
      ],
      [
        "r",
        "fixed seed-type rate (lb/1,000 sq ft)"
      ],
      [
        "p",
        "project factor"
      ],
      [
        "w",
        "waste (%)"
      ]
    ],
    "note": "Rates and project multipliers are planning assumptions; follow the selected seed product label. Five-pound bag count rounds up."
  },
  "externalEvidence": null,
  "contract": {
    "compute": "const S = { fescue:6, bluegrass:4, ryegrass:8, bermuda:3, mix:5 }; const P = { new:1, overseed:0.5, repair:1.2 }; const rate = (S[seedType] || 5)*(P[project] || 1); const area = length*width; const seedLb = area/1000*rate*(1+waste/100); return { area, areaSqft: area/1000, seedLb, seedKg: seedLb*0.45359237, bags: Math.ceil(seedLb/5) };",
    "inputs": [
      {
        "name": "length",
        "type": "number",
        "default": 50,
        "min": 1,
        "max": 5000,
        "step": 1,
        "slider": true
      },
      {
        "name": "width",
        "type": "number",
        "default": 30,
        "min": 1,
        "max": 5000,
        "step": 1,
        "slider": true
      },
      {
        "name": "project",
        "type": "select",
        "default": "new",
        "options": [
          {
            "value": "new"
          },
          {
            "value": "overseed"
          },
          {
            "value": "repair"
          }
        ]
      },
      {
        "name": "seedType",
        "type": "select",
        "default": "fescue",
        "options": [
          {
            "value": "fescue"
          },
          {
            "value": "bluegrass"
          },
          {
            "value": "ryegrass"
          },
          {
            "value": "bermuda"
          },
          {
            "value": "mix"
          }
        ]
      },
      {
        "name": "waste",
        "type": "number",
        "default": 10,
        "min": 0,
        "max": 30,
        "step": 1,
        "slider": true
      }
    ],
    "outputs": [
      {
        "name": "area",
        "precision": 0,
        "unit": "sq ft"
      },
      {
        "name": "areaSqft",
        "precision": 3,
        "unit": "x1000 sq ft"
      },
      {
        "name": "seedLb",
        "precision": 2,
        "unit": "lb"
      },
      {
        "name": "seedKg",
        "precision": 2,
        "unit": "kg"
      },
      {
        "name": "bags",
        "precision": 0,
        "unit": ""
      }
    ],
    "interpret": null
  }
}