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How Crop Calendar Verifies Planting Dates

Every planting or harvest window on this site must come from a cited USDA or extension source. If no verified source exists for a crop and region, we do not publish a page for it.

Field crop windows

The field crop pages use the USDA National Agricultural Statistics Service publication Field Crops Usual Planting and Harvesting Dates, October 2010 edition, hosted by Cornell University's Mann Library. Each range runs from about 5% to about 95% of the crop planted or harvested, based on state progress data. The edition is older, so we label every page with it and tell you to check current NASS Crop Progress reports and your extension office.

Vegetable and garden crop windows

Vegetable windows come from university extension planting calendars for Minnesota, Illinois, Missouri, Arkansas, North Carolina, Florida, Utah, Arizona, Oregon and New Hampshire. Each page links the exact extension page used. Other states are not covered until a verified source is added.

Ranges and caveats

We show ranges, never single dates, and every page carries a frost-date caveat. Statewide averages hide differences between regions in the same state.

Review dates

Each data row carries a last-verified date, and each factual page shows when it was last reviewed. The full table is published as planting-windows.json.

Guides

Guides are written from published extension and government sources. Where a guide cannot cite a source for a specific window, it explains the method instead and sends you to your local extension office.