The Home Almanac

Vol. I, MMXXVIThe American home, in season.Across all fifty states

When to start seeds indoors

Most gardens start the first seeds indoors in late winter to March, working back from the last frost. Set your place and the Almanac lists every crop's indoor start and transplant date.


First seed start Set your place
Your last frost

First indoor seed start, every year.

Why count back from the last frost

Indoor seed starting is about giving slow or frost-sensitive crops a head start without letting them outgrow their pots. The right start date is a fixed number of weeks before your average last spring frost, which varies by weeks across the country.

The table below converts those offsets into real dates once you set your place. Crops without a transplant week are marked n/a because they are typically direct-sown or grown to full size indoors.

Crops to start indoors

Generic offsets shown. Set your place for dated windows.

CropStart indoorsTransplant
Tomato 6 weeks before last frost 1 week after last frost
Pepper 8 weeks before last frost 2 weeks after last frost
Eggplant 8 weeks before last frost 2 weeks after last frost
Cucumber 3 weeks before last frost 1 week after last frost
Zucchini 3 weeks before last frost 1 week after last frost
Winter squash 3 weeks before last frost 1 week after last frost
Pumpkin 3 weeks before last frost 1 week after last frost
Melon 4 weeks before last frost 2 weeks after last frost
Lettuce 8 weeks before last frost 4 weeks before last frost
Kale 6 weeks before last frost 2 weeks before last frost
Swiss chard 5 weeks before last frost 1 week before last frost
Leek 10 weeks before last frost 0 weeks after last frost
Broccoli 6 weeks before last frost 2 weeks before last frost
Cauliflower 6 weeks before last frost 2 weeks before last frost
Cabbage 6 weeks before last frost 3 weeks before last frost
Brussels sprouts 6 weeks before last frost 2 weeks before last frost
Basil 6 weeks before last frost 2 weeks after last frost
Parsley 8 weeks before last frost 2 weeks before last frost

Offsets follow standard horticultural practice. Sources on the methodology page.

Last spring frost for major cities

CityLast spring frost
New York NY March 26
Los Angeles CA January 9
Chicago IL April 11
Houston TX January 30
Phoenix AZ January 8
Philadelphia PA April 2
San Antonio TX February 26
San Diego CA January 6
Dallas TX March 8
Austin TX February 20
Miami FL January 20
Tampa FL January 20
Atlanta GA March 25
Seattle WA March 13
Denver CO May 3
Boston MA April 4
Las Vegas NV January 24
Portland OR March 29
Minneapolis MN April 30
Detroit MI April 30
Nashville TN March 31
Charlotte NC March 30
Honolulu HI April 12
Anchorage AK May 1

Related tools

Full frost and planting calendar, The Home Year

Questions, answered plainly

Which seeds should I start indoors first?

Leeks, peppers, and eggplant are the earliest indoor starts, often ten to eight weeks before the last frost. Tomatoes follow at six weeks. The table above lists every crop with an indoor start window.

What does "weeks before last frost" mean?

It is a countdown from the average date of your last spring frost. A crop marked "8 weeks before" gets started indoors eight weeks ahead of that date. The Almanac converts the offset to a real date once you set your place.

Can I start these seeds outdoors instead?

Some crops on the list can also be direct-sown; the planting calendar shows both methods. The list here is limited to crops that gain from an indoor head start in most gardens.

How this page was made

Data source: NOAA 30-year climate normals via the site dataset, plus crop offsets from the site crops library. Method: each indoor start date is the station's mean last spring frost plus the crop's indoorStartWeeks offset. Verified 2026-06-12. Full notes on the methodology page.