Vegetable Planting Window Calculator

How the Vegetable Planting Window Calculator Works

Calculates a recommended indoor-seed-starting date and transplant or direct-sow window for common vegetables, offset from your own local average last-frost date using standard extension-service and almanac planting guidelines. You supply the last-frost date yourself — a USDA hardiness zone number describes minimum winter temperature, not a specific frost date, and zones span a wide range of actual last-frost dates depending on local microclimate, so this tool never tries to derive one from a zone alone. Look up your local average last-frost date from your county extension office or a local almanac source before using this calculator.

Formula

Planting Date = Last Frost Date ± Weeks (per-vegetable offset)

Cold-hardy crops (lettuce, carrots) are direct-sown a couple of weeks before the last frost since light frost does not damage them. Frost-sensitive crops (tomatoes, peppers, beans, corn, squash, cucumbers) are either started indoors weeks ahead and transplanted after the frost risk passes, or direct-sown only after the last frost date.

Calculation Example

With a last-frost date of June 1: Tomatoes start indoors around April 20 (6 weeks before) and transplant outdoors June 8–15 (1–2 weeks after frost).

Frequently Asked Questions

Why not just enter my USDA hardiness zone?

A hardiness zone describes average minimum winter temperature, not a last-frost date — two locations in the same zone can have last-frost dates weeks apart. Look up your own local average last-frost date (your county extension office or a local almanac is the standard source) and enter that directly.

Is this an exact planting date?

No — treat it as general guidance based on published averages. Actual timing still varies with your microclimate, that particular year's weather, and the specific variety you are growing.

Browse more

See all garden tools.

Calculator Inputs