Vegetable Planting Calendar (+ Free Seed Starting Calculator)

Type your last frost date. Get your seed-starting, transplant and direct-sow dates for 17 crops in seconds.

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Most planting mistakes come down to timing: seeds started too early get leggy, and warm-season crops set out too soon get hit by a late frost. Every date on a seed packet is counted from one number, your average last spring frost date. Enter it below and the calculator does the counting for you.

Want the whole backyard plan, not just the dates?

The Self-Sufficient Backyard is a step-by-step homesteading guide covering garden layout, food preservation, water and more on a small lot.

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Free Seed Starting Calculator

Your average last spring frost date Show

Timing from University of New Hampshire Extension's "When to Plant Your Vegetable Garden" table (start of each range used for the start date). Always check your seed packet; varieties differ.

Find your last frost date

Your last frost date is the average date of the last 32°F night in spring. It is an average, not a guarantee: frost can still come after it. Good places to find yours:

Your county Cooperative Extension office (search "[your county] extension last frost date").
NOAA NCEI climate normals for the weather station nearest you.

The USDA Plant Hardiness Zone Map tells you your zone from your ZIP code, but zones are based on average coldest winter temperature, not frost dates. Two places in the same zone can have last frost dates weeks apart, so use a local frost date for this calculator.

Every date is counted backwards or forwards from your last frost date.

How the planting calendar works

Vegetables fall into two groups. Cool-season crops (broccoli, cabbage, kale, lettuce, onions, peas, radishes) handle light frost and go out weeks before the last frost. Warm-season crops (tomatoes, peppers, eggplant, cucumbers, squash, beans, corn, basil) are killed by frost and need warm soil, so they go out after it.

Crop	Weeks indoors	Safe to set out
Tomato	6-8	1-2 weeks after last frost
Pepper	8-10	2 weeks after
Broccoli	4-6	2-4 weeks before
Lettuce	4-5	3-4 weeks before
Onion	8-10	4 weeks before
Cucumber	3-4 (or direct sow)	1-2 weeks after

Source: University of New Hampshire Extension.

Starting seeds indoors

Use a clean container and a sterile seed-starting mix, sow at the depth on the packet (roughly two to three times the seed's width), and keep the mix moist but not waterlogged. Most vegetable seeds germinate best in warm soil; Rutgers Cooperative Extension lists optimum germination temperatures of about 75-90°F for common crops, which is why a heat mat helps peppers and tomatoes.

Once seedlings emerge, light is the limit. A windowsill rarely gives enough; fluorescent or LED shop lights a few inches above the seedlings, on for 14-16 hours a day, keep them short and sturdy. Sowing too early is a common mistake that leaves tall, root-bound plants (University of Maryland Extension).

Simple indoor seed-starting setup.

Hardening off

About a week before transplanting, put seedlings outside in a sheltered spot for a couple of hours, then bring them back in. Increase the time each day until they stay out overnight. Skipping this can scorch or stunt plants raised indoors.

Direct sowing

Beans, corn, carrots, peas, radishes and beets do best sown straight into the garden. Root crops dislike transplanting, and beans and corn grow fast in warm soil. A soil thermometer is the best guide: carrots and corn want about 60°F, cucumbers and squash about 70°F (UNH Extension).

Seeds and a planner

Seeds for the calendar

True Leaf Market sells vegetable, herb and microgreen seeds and seed-starting supplies.

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Botanical Interests sells vegetable, herb and flower seed packets with growing notes on every packet.

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Keep your dates in one place

Our Garden Planner is a digital download: a GoodNotes garden binder, printable seed and planting logs, and a seed-starting spreadsheet that works from your own frost date. Nothing is shipped.

See the Garden Planner on Etsy

FAQ

When should I start seeds indoors?

Count back from your average last spring frost date by the number of weeks each crop needs. University of New Hampshire Extension gives 6-8 weeks for tomatoes and 8-10 weeks for peppers, for example.

How do I find my last frost date?

Ask your county Cooperative Extension office or use NOAA climate normals for the nearest weather station. Hardiness zones describe winter low temperatures, not frost dates, so use them only as a rough guide.

Is the USDA hardiness zone the same as my frost date?

No. The USDA Plant Hardiness Zone Map is based on the average annual extreme minimum winter temperature. It helps choose perennials that survive winter; it does not give planting dates.

What does hardening off mean?

Gradually getting indoor seedlings used to sun, wind and cooler nights over about a week before transplanting, starting with a couple of hours outside a day.

Can I plant tomatoes on my last frost date?

Average last frost dates still carry a chance of frost afterwards. Extension guidance is to set out tomatoes 1-2 weeks after the last frost, once the soil has warmed.

Why are my seedlings tall and floppy?

Usually too little light or seeds sown too early. University of Maryland Extension notes that sowing too early is a common mistake that produces tall, root-bound plants.

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Disclaimer

General guidance only. Dates are estimates calculated from the average last frost date you enter and published Extension timing ranges; weather varies year to year and frost can occur after the average date. Always check your seed packets and your local Cooperative Extension office. We may earn a commission from links on this page.