Irrigation

Sprigg's irrigation engine is the heart of the platform. Every day, it analyzes weather data, disease risk, soil conditions, and your water budget to generate per-zone watering recommendations. This page explains how it all works.

How the AI Advisor Works

Each day, Sprigg runs an analysis cycle for your property. The AI advisor (powered by Claude) receives a comprehensive data package and produces zone-by-zone watering recommendations.

Input Data

The advisor considers:

• Current weather — Temperature, humidity, wind speed, dew point, cloud cover
• 5-day forecast — 3-hour interval forecasts including precipitation probability
• Disease risk scores — Per-disease risk levels based on temperature and humidity patterns
• Weekly water budget — Target vs. applied vs. rainfall for each zone
• Run history — Last 7 days of irrigation events from your controller
• Calendar events — Recent and upcoming lawn care activities (e.g., fungicide applied, aeration scheduled)
• Property context — Grass type, USDA zone, region, soil type, expertise level

Output

For each zone, the advisor produces:

• Whether to water or skip
• Runtime in minutes
• Number of cycles and soak time (for sloped zones)
• Estimated water amount in inches
• Suggested start time
• Detailed reasoning (multiple bullet points explaining the decision)

Active vs. Audit Mode

Sprigg supports two irrigation modes that control how recommendations are acted upon:

Start in Audit mode to review Sprigg's recommendations for a few days before switching to Active mode for fully automated irrigation.

Daily Recommendation Flow

Here's what happens behind the scenes each day:

1. Cron trigger — An hourly cron job checks which properties are due for analysis, sharded by timezone to avoid thundering herd issues.
2. Data collection — Weather, forecast, disease risk, water budget, and run history are gathered for the property.
3. AI analysis — The data package is sent to Claude Sonnet, which generates per-zone recommendations with detailed reasoning.
4. Safety validation — Recommendations are validated against safety constraints (max 0.75" per event, min 0.05" per event).
5. Storage & notification — Results are stored in the analysis history and the user is notified.
6. Execution (Active mode only) — Watering commands are queued and sent to your controller, with retry logic for failures.

Manual Watering

You can manually water zones at any time, regardless of mode. Go to the Irrigation History page and use the manual watering controls to:

• Start a specific zone for a set duration
• Log manual watering you've already done (enter inches or duration)
• Stop all running zones

Manual watering is tracked in your water budget, so Sprigg accounts for it in future recommendations. You can also use the Ask Sprigg chat to start and stop zones with natural language.

Water Budget

Sprigg tracks a weekly water budget for each zone to ensure your lawn gets the right amount of water — not too much, not too little.

How the Target is Calculated

The weekly water target starts from your configured base (default 1.0"/week) and is adjusted by:

• Evapotranspiration (ET) — Actual ET from weather stations or estimated via the Hargreaves method, scaled by a 0.8 crop coefficient
• Shade factor — Shaded zones need less water (0.5x to 1.0x adjustment)
• Seasonal patterns — Based on latitude and day of year

Budget Tracking

For each zone, the budget tracks:

• Target inches — Adjusted weekly target
• Applied inches — Water delivered by irrigation
• Rainfall inches — Effective rainfall captured (adjusted by soil type efficiency)
• Remaining inches — What's still needed this week
• Pace status — Compares actual progress to expected progress for the day of the week

Pace Status Levels

Cycle-Soak

For zones on slopes or with compacted soil, applying water too fast causes runoff. Sprigg automatically splits long watering sessions into shorter cycles with soak periods between them.

The cycle-soak calculation considers:

• Soil infiltration rate — How fast water absorbs into the ground
• Precipitation rate — How fast your sprinklers deliver water
• Slope factor — Steeper slopes reduce effective infiltration

If the precipitation rate exceeds the infiltration rate, Sprigg splits the watering into cycles where each cycle delivers only as much water as the soil can absorb, then pauses for a soak period to let it soak in before the next cycle.

Decision History

Every irrigation decision is logged with full context — the reasoning, weather conditions at the time, disease risk level, and outcome. You can review the decision history in the Irrigation History page to understand why Sprigg watered or skipped on any given day.

Up to 500 decision log entries are retained per property, with the oldest entries automatically trimmed.