About PlantWise

PlantWise is a free, data-driven gardening reference that helps home gardeners know exactly when to plant vegetables, herbs, and fruits in their USDA hardiness zone. We don't sell anything — we just compile public agricultural data into useful, practical guides.

Our Methodology

Every planting schedule on PlantWise is generated algorithmically from verified public datasets, not written by hand or guessed. Here's how it works:

Step 1 We pull average last and first frost dates for each USDA zone from NOAA Climate Normals (1991–2020).

Step 2 We apply each plant's frost tolerance and minimum soil temperature to calculate the safe outdoor planting window.

Step 3 For plants that need indoor starts, we count back 6–8 weeks from the transplant date to get the seed-starting date.

Step 4 Harvest windows are calculated from the planting date plus the plant's days-to-maturity range, capped at first frost.

Important caveat: These are averages based on 30-year climate normals. Your specific microclimate — elevation, proximity to water, urban heat island effects — may shift your actual frost dates by 1–2 weeks. Always check with your local Cooperative Extension office for the most accurate local guidance.

Data Sources

Frost & Climate Data
NOAA National Centers for Environmental Information — U.S. Climate Normals 1991–2020. ~15,000 weather stations across the US.

Hardiness Zones
USDA Agricultural Research Service — Plant Hardiness Zone Map (2023 edition).

Growing Requirements
Cooperative Extension Services: NC State Extension, Penn State Extension, University of Florida IFAS, Cornell Cooperative Extension.

Companion Planting
Cornell University Cooperative Extension and published agronomic research on companion planting interactions.

Contact

Found an error in our data? Have a suggestion? We'd love to hear from you.
Email: hello@plantwise.garden