# Garden Calculators – Growing Degree Days

> Garden Calculators – Growing Degree Days is a paid API for AI agents from garden-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates daily and cumulative growing degree days (GDD) from daily temperature min/max pairs, with configurable base temperature, upper cutoff, and crop presets.

## Facts

- Endpoint: GET https://garden-calc.x402tookit.com/growing-degree-days?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/garden-calculators-growing-degree-days-b74c231b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MqtFLHeG3dV1conrB28XR

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability garden-calculators-growing-degree-days-b74c231b
```

Example prompt: Calculate growing degree days for my corn crop using these 10 days of temperature data in Fahrenheit: '48:72; 52:80; 55:88; 50:75; 53:82; 57:90; 45:68; 51:77; 54:85; 56:91' — I want daily and cumulative GDD totals, and let me know which day passes 300 GDD.

## When to prefer this

Choose this endpoint when you need to compute growing degree day accumulations from raw daily temperature records, particularly for crop phenology tracking, pest emergence forecasting, or agricultural planning. It supports both standard crop presets (corn, wheat, warm-season, cool-season) and fully custom base/upper cutoff temperatures, and can pinpoint the day a GDD target is reached — making it more useful than a simple average calculator when you need day-by-day breakdowns and cumulative totals.

## Known failure modes

- Missing 'days' parameter returns an error — at least one min:max pair is required
- Malformed day entries (wrong separator or non-numeric values) cause parse errors
- Exceeding 400 days in the input may be rejected or truncated
- Invalid crop preset name returns an error or falls back to default base temperature
- Conflicting crop preset and explicit baseTemp may cause ambiguity in results
- Temperatures outside valid range for the unit (e.g. below -10F base) may return validation errors

## How this service works

Growing degree days from daily lows and highs with a base temperature and upper cutoff: daily and cumulative totals.

## Output

Returns an array of daily records each containing the day number, min and max temperatures, daily GDD, simple average GDD, and cumulative GDD to that day. Also returns total GDD, day count, the base and upper cutoff temperatures used, the calculation method, temperature unit, and optionally the day on which a target GDD total is first reached.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "days"
     ],
     "properties": {
      "crop": {
       "type": "string",
       "description": "Preset base temperature: corn, warm-season, cool-season or wheat (or give baseTemp)"
      },
      "days": {
       "type": "string",
       "description": "Daily minimum:maximum pairs separated by semicolons or new lines, for example '48:72; 52:80; 55:88' (up to 400 days)"
      },
      "unit": {
       "type": "string",
       "description": "f (default) or c for the temperatures and results"
      },
      "baseTemp": {
       "type": "number",
       "description": "Base temperature in the chosen unit (below it plants make no growth), -10 to 80 F or -23 to 27 C"
      },
      "targetGdd": {
       "type": "number",
       "description": "A GDD total to reach, to find the day it is passed"
      },
      "upperTemp": {
       "type": "number",
       "description": "Upper cutoff temperature in the chosen unit (default 86 F or 30 C)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "days": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "day": {
          "type": [
           "null",
           "number"
          ]
         },
         "gdd": {
          "type": [
           "null",
           "number"
          ]
         },
         "max": {
          "type": [
           "null",
           "number"
          ]
         },
         "min": {
          "type": [
           "null",
           "number"
          ]
         },
         "cumulativeGdd": {
          "type": [
           "null",
           "number"
          ]
         },
         "simpleAverageGdd": {
          "type": [
           "null",
           "number"
          ]
      
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/garden-calculators-growing-degree-days-b74c231b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from garden-calc.x402tookit.com](https://www.zero.xyz/host/garden-calc.x402tookit.com/llms.txt)