TL;DR
All vegetable gardening revolves around two dates: last spring frost and first fall frost. Everything else is measured from these dates. Find your zone, find your frost dates, and all other timing falls into place. A frost date calendar is more useful than any other garden planning tool.
Average Frost Dates by USDA Zone
These are statistical averages. Local geography (valleys frost earlier; hilltops and urban areas frost later) creates variation.
| Zone | Approx. Last Spring Frost | Approx. First Fall Frost | Approx. Growing Season | |------|--------------------------|--------------------------|----------------------| | Zone 3 | May 15 - June 1 | August 15 - September 1 | 75-90 days | | Zone 4 | May 1-15 | September 15 - October 1 | 130-145 days | | Zone 5 | April 15-30 | October 1-15 | 165-180 days | | Zone 6 | April 1-15 | October 15-30 | 185-195 days | | Zone 7 | March 15 - April 1 | October 30 - November 15 | 200-220 days | | Zone 8 | February 15 - March 15 | November 15 - December 1 | 240-260 days | | Zone 9 | February 1-15 | December 1-15 | 270-290 days | | Zone 10-11 | No hard freeze | No hard freeze | Year-round |
Planting Timeline Reference
All dates expressed relative to last frost date (LFD).
Cool-Season Crops (Plant Before Last Frost)
| Crop | Outdoor Direct Sow | Transplant Outdoors | Notes | |------|------------------|---------------------|-------| | Peas | 6-8 weeks before LFD | Not transplanted | As soon as soil is workable | | Spinach | 6-8 weeks before LFD | Not transplanted | Tolerates light frost | | Kale | 4-6 weeks before LFD | 4-6 weeks before LFD | Very frost hardy | | Lettuce | 4-6 weeks before LFD | 4-6 weeks before LFD | Light frost tolerant | | Broccoli | Start indoors 6-8 wks before LFD | 4 weeks before LFD | | | Cabbage | Start indoors 6-8 wks | 3-4 weeks before LFD | | | Carrots | 3-4 weeks before LFD | Not transplanted | | | Beets | 4-6 weeks before LFD | Not transplanted | | | Radishes | 4-6 weeks before LFD | Not transplanted | 25-day maturity | | Onions (sets) | 3-4 weeks before LFD | 3-4 weeks before LFD | | | Garlic | Fall planting for summer harvest | — | Plant in October; harvest following July |
Warm-Season Crops (Plant After Last Frost)
| Crop | Outdoor Direct Sow | Start Indoors (weeks before LFD) | Notes | |------|------------------|----------------------------------|-------| | Beans | At LFD | Not recommended | Resents transplanting | | Corn | At LFD or 1 week after | Not recommended | Sow directly | | Cucumbers | 1 week after LFD | 2-3 weeks before LFD | | | Squash (summer) | At LFD | 2-3 weeks before LFD | Fast-growing; direct sow often better | | Squash (winter) | At LFD | 3-4 weeks before LFD | Long maturity; earlier start helps | | Tomatoes | Not direct sown | 6-8 weeks before LFD | Always transplant | | Peppers | Not direct sown | 8-10 weeks before LFD | Slow; earliest start | | Pumpkins | 1 week after LFD | 3-4 weeks before LFD | Long maturity | | Melons | 1-2 weeks after LFD | 3-4 weeks before LFD | Long maturity |
Zone-Specific Planting Windows
Zone 3-4 (Minnesota, Wisconsin, Vermont, etc.)
Short growing season demands maximum efficiency. Start warm-season crops indoors earlier (8-10 weeks for tomatoes, 10-12 for peppers). Use cold-hardy varieties. Consider row covers for frost protection in late summer.
Priority crops: Potatoes (reliable calorie crop), beans (fast-maturing varieties), kale (extremely cold-hardy for extended harvest), beets and carrots.
Key dates (approximate):
- Start tomatoes indoors: March 1-15
- Transplant outdoors: May 25 - June 1
- First fall frost: September 15-30
- Last harvest: Mid-October with row covers
Zone 5-6 (Ohio, Pennsylvania, Oregon, etc.)
Key dates (approximate):
- Start tomatoes indoors: March 15 - April 1
- Transplant outdoors: May 1-15
- First fall frost: October 1-15
- Direct sow greens for fall: August 1-15
Zone 7-8 (Virginia, Tennessee, Pacific Northwest lowlands, etc.)
Key dates (approximate):
- Start tomatoes indoors: February 15 - March 1
- Transplant outdoors: April 1-15
- Fall crop planting window: August 15 - September 15
- Winter growing: Cold-hardy greens through mild winters
Zone 9+ (California lowlands, Florida, Gulf Coast)
Two distinct growing seasons: a spring/summer season for warm crops and a fall/winter season for cool crops.
Spring/summer: Plant warm crops in January-March. Fall/winter: Plant cool crops in September-November. This is the primary gardening season in the hottest parts of these zones (summer heat stops most crops).
Succession Planting
For continuous harvest rather than a single seasonal flush, plant the same crop every 2-3 weeks through its planting window.
Example (lettuce in Zone 6):
- March 15: first planting
- April 1: second planting
- April 15: third planting
- Harvest from first planting begins May 1-15
- Continue succession every 2 weeks through June
This produces 3-4 months of continuous harvest rather than 3-4 weeks from a single planting.
Crops with short maturity (radishes, spinach, lettuce, beans) benefit most from succession planting.
Sources
- USDA Plant Hardiness Zone Map
- University of Minnesota Extension - Vegetable Planting Calendar
- University of California Cooperative Extension - Planting Guide
Frequently Asked Questions
How do I find my USDA Hardiness Zone?
The USDA Plant Hardiness Zone Map at planthardiness.ars.usda.gov allows you to enter your zip code to find your exact zone. Alternatively, zones range roughly as follows: Zone 4 covers the northern Midwest and New England (Minnesota, northern Wisconsin, Vermont). Zone 5-6 covers most of the Midwest, Mid-Atlantic, and Pacific Northwest. Zone 7-8 covers the South, Mid-South, and western coastal areas. Zone 9-11 covers Florida, southern California, and Hawaii.
What does 'last frost date' mean for planting?
The last frost date (LFD) is the average date of the final frost in spring — after this date, the risk of freezing temperatures is statistically low (though not zero). Frost-tender crops (tomatoes, peppers, cucumbers, beans, squash) cannot be planted outdoors before the last frost date. Cold-hardy crops (kale, spinach, peas, carrots) can be planted 4-6 weeks before the LFD. The last frost date is a statistical average — in any given year, a late frost may occur after the average date.
Can you garden year-round in the United States?
Year-round gardening is possible in Zone 8 and warmer (most of the South, Pacific Coast). In Zones 6-7, cold-hardy crops (kale, spinach, chard, garlic, root vegetables) can be grown through much of winter with row covers or cold frames. In Zones 4-5, the outdoor growing season runs approximately May-October; indoor growing (sprouts, microgreens) is the realistic year-round option.