agronomy.INFO

Open source

Agricultural data tools

tools for
agronomic guidance

Free, open-source web tools built for Midwest row crop production — tracking growing degree units, stage timing, and crop development from planting to harvest.

View tools GitHub

Tools

Emergence Calculator

Predict corn and soybean emergence date using soil temperature, moisture, and field conditions from planting date forward.

Corn Soybeans Open tool

Corn GDU Tracker

Track growing degree unit accumulation from planting through black layer. Estimates current growth stage, leaf stage, and days to maturity using live weather data.

Corn Weather Open tool

Soybean GDU Tracker

Monitor soybean development from emergence through R8 maturity. Maps heat unit accumulation to reproductive growth stages using crop-specific base temperatures.

Soybeans Weather Open tool

Rainfall Tracker

Compare cumulative in-season rainfall against historical averages for your location. Identify drought stress windows and excessive rainfall events by growth stage.

Precip Weather Open tool

Corn Irrigation Coach

Irrigation timing and rate recommendations based on crop growth stage, evapotranspiration, and recent rainfall for Midwest corn production.

Corn Irrigation Open tool

Generate GDU and Rainfall reports across multiple locations for newsletters or quick comparison across areas. Input locations and planting dates.

Corn Soybeans Open tool

Corn Replant Calculator — coming soon

Additional tools for Midwest row crop production are in development.

More in-season tools coming soon

Additional tools for Midwest row crop production are in development.

Coming soon

Useful resources

US Drought Monitor

droughtmonitor.unl.edu

Synoptic Weather

At a glance

6

Tools available

Free

Always & forever

Midwest

ZIP code coverage

About

Data sources

Weather data is pulled live from Open-Meteo's free API using ZIP code coordinates. No API key required. Includes historical actuals and near-term forecast data.

How it works

Enter your planting date and ZIP code. The tool accumulates GDUs from planting forward and maps the total to known growth stage thresholds for each crop.

Who it's for

Built for agronomists, crop advisors, and farmers in the Midwest who want a quick, accurate read on crop development without digging through weather records.

Open source

All tools are MIT-licensed and published on GitHub. Contributions, forks, and feedback are welcome. Built with plain HTML — no build step required.