Planting & Harvest Dates

USDA Zone Lookup

Enter your ZIP code to find your USDA plant hardiness zone, its temperature range, your frost-free growing days, and which plants thrive there.

How to use the USDA zone lookup

Type your five-digit US ZIP code into the box and press Find My Zone. The tool shows your USDA plant hardiness zone, the average winter low temperature for that zone, your typical frost-free growing days, and a quick list of crops that do well in your range. From there you can jump straight to a planting calendar tailored to your area.

What your hardiness zone tells you

The USDA Plant Hardiness Zone Map is the standard reference gardeners use to decide which plants will survive the winter in their area. It is built from the average annual lowest winter temperature, grouped into 10-degree Fahrenheit zones and 5-degree half-zones. When a plant tag says “hardy to Zone 5,” it means that plant can normally survive the winter lows of Zone 5 and any milder zone. Matching plants to your zone is the easiest way to avoid losing perennials, shrubs, and trees to cold.

What zones do not tell you

Hardiness zones only describe winter cold. They say nothing about summer heat, humidity, rainfall, soil, or the length of your growing season, all of which also shape what grows well. Two regions in the same zone can feel completely different in summer. That is why your frost-free days, shown alongside your zone here, are so useful: they tell you how long your season is, which matters as much as winter hardiness for vegetable gardeners.

From zone to a planting plan

Once you know your zone, use it to choose perennials, fruit trees, and shrubs rated to survive your winters, and lean on your frost dates to time vegetables. Colder zones favor cold-hardy crops and a compressed season, milder zones open up heat lovers and longer harvests, and the warmest zones allow year-round growing with summer shade. Pair this lookup with a frost date calculator and a planting calendar to turn your zone into a season-long schedule.

Tips for working with your zone

  • Buy perennials, trees, and shrubs rated for your zone or one colder for a safety margin.
  • Treat tender, warmer-zone plants as annuals or overwinter them indoors.
  • Use mulch, row cover, and cold frames to nudge borderline plants through winter.
  • Look for warm microclimates near south-facing walls and avoid frost-pooling low spots.
  • Combine your zone with frost dates and rainfall for the full picture before planting.

Frequently Asked Questions

What is a USDA plant hardiness zone?

A USDA hardiness zone is a region defined by its average annual lowest winter temperature. The map divides the country into zones in 10-degree Fahrenheit bands, each split into an "a" and "b" half of 5 degrees. The zone tells you, at a glance, which perennial plants, shrubs, and trees can reliably survive winter where you live. It is the single most useful number for choosing long-lived plants.

How do I find my hardiness zone?

The quickest way is to enter your ZIP code above. We match it to the zone for your region using the same data behind the official USDA map. You can also look up the full interactive map on the USDA website. Keep in mind that large ZIP areas and local microclimates mean your exact yard may sit slightly warmer or colder than the regional zone.

What does the a or b after the number mean?

Each numbered zone spans a 10-degree Fahrenheit range and is divided into two 5-degree halves. The "a" half is the colder portion and the "b" half is the warmer one. For example, Zone 6a averages a winter low of -10 to -5 degrees Fahrenheit, while Zone 6b averages -5 to 0. The half-zone matters most for plants growing near the edge of their cold tolerance.

Does my zone tell me when to plant?

Not directly. Hardiness zones describe winter cold to help you choose what will survive, not when to sow or transplant. For timing, you want your frost dates and a planting calendar. This tool shows your frost-free days, and you can follow the link to a planting calendar that lays out indoor sowing and transplant dates for your area.

Can I grow plants from a warmer zone than mine?

Often, yes, with some effort. Tender plants rated for warmer zones can be grown as annuals, brought indoors over winter, or protected with mulch, row cover, and cold frames. Choosing a sheltered, sunny microclimate near a south-facing wall can also buy you part of a zone. Just know these plants may need extra care to survive a hard winter.

Why does the same zone appear in very different places?

Because zones are based only on winter low temperatures, places with very different summers and rainfall can share a zone. A cool, damp coastal area and a hot, dry inland one might both be Zone 8 if their winter lows match. That is why zone is a starting point: also consider your summer heat, humidity, rainfall, and first and last frost dates when choosing plants.

How accurate is the ZIP code lookup?

It is a close regional estimate. We map the first three digits of your ZIP to its typical zone, which is accurate for most gardeners. Mountainous and coastal regions can vary within a single ZIP area, so if your ZIP is not listed or your conditions feel different, check a neighboring ZIP or the detailed USDA map for your exact address.

More Tools to Explore

Frost Date Calculator Last and first frost by ZIP code Open tool → Planting Calendar When to plant by ZIP code Open tool → Seed Starting Date Calculator When to start seeds indoors Open tool →

GardenCalc Editorial Team

Horticulture Writers & Master Gardeners

Our calculators and guides are written and fact-checked by gardeners with hands-on experience in vegetable production, soil management, and home landscaping.