{
  "metadata": {
    "title": "Storm Lake Field Guide — Root Crops of Zone 5b",
    "author": "Barbara Cintron",
    "location": "Story County, Iowa, USA",
    "usda_zone": "5b",
    "last_frost_date": "2026-04-15",
    "first_frost_date": "2026-10-15",
    "frost_variance_days": 3,
    "version": "1.0",
    "published": "2026-07-17T05:50:00Z"
  },
  "crops": [
    {
      "id": "turnip",
      "common_name": "Winter Turnip",
      "scientific_name": "Brassica rapa var. rapa",
      "planting_windows": [
        {
          "start": "2026-08-10",
          "end": "2026-09-05"
        }
      ],
      "soil_temp_range_celsius": {
        "min": 14,
        "max": 18
      },
      "root_depth_cm": {
        "min": 25,
        "max": 35
      },
      "frost_tolerance_celsius": -8,
      "days_to_harvest": {
        "min": 55,
        "max": 65
      },
      "spacing_cm": 15,
      "storage_protocol": {
        "temperature_celsius": 0,
        "humidity_percent": 95,
        "medium": "sand"
      },
      "source": "https://extension.iastate.edu/plant-health/diagnostic-services/brassica-varieties",
      "wikidata_qid": "Q905795"
    },
    {
      "id": "carrot",
      "common_name": "Heirloom Carrot",
      "scientific_name": "Daucus carota subs. sativus",
      "planting_windows": [
        {
          "start": "2026-04-15",
          "end": "2026-05-10"
        },
        {
          "start": "2026-08-01",
          "end": "2026-08-20"
        }
      ],
      "soil_temp_range_celsius": {
        "min": 7,
        "max": 12
      },
      "root_depth_cm": {
        "min": 40,
        "max": 60
      },
      "frost_tolerance_celsius": -5,
      "mulch_required_cm": 30,
      "days_to_harvest": {
        "min": 70,
        "max": 90
      },
      "overwinter_viable": true,
      "harvest_window_extended": true,
      "source": "https://naldc.nal.usda.gov/catalog?page=1&q=carrot+zone+5b"
    },
    {
      "id": "parsnip",
      "common_name": "Parsnip",
      "scientific_name": "Pastinaca sativa",
      "planting_windows": [
        {
          "start": "2026-03-25",
          "end": "2026-04-10"
        }
      ],
      "soil_temp_range_celsius": {
        "min": 5,
        "max": 10
      },
      "root_depth_cm": {
        "min": 50,
        "max": 75
      },
      "frost_tolerance_celsius": -15,
      "snow_cover_required": true,
      "days_to_harvest": {
        "min": 120,
        "max": 140
      },
      "minimum_frosts_before_harvest": 3,
      "earliest_harvest_date": "2026-11-01",
      "preferred_soil": "loam",
      "source": "https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1034&context=horticulturefacpub"
    }
  ],
  "climate_parameters": {
    "latitude": 42.33,
    "longitude": -93.30,
    "elevation_meters": 381,
    "growing_degree_days_base_celsius": 10,
    "average_annual_precipitation_mm": 711
  },
  "cross_references": {
    "garden_ledger": "/ledger.html",
    "anchor_protocol": "/anchor.html",
    "operations_home": "/"
  }
}