Grow by Season

Seed-starting calendar

Count back from your last spring frost: start leeks and celery 10 to 12 weeks before it, peppers and onions 8 to 10, tomatoes and the cabbage family 6 to 8, basil and marigolds 4 to 6. Type your ZIP code for your own dates.

Drawing of a seed packet

Example garden, zone 7a · last frost Apr 15

Week by week

  1. Week of Jan 2112 weeks before your last frost

  2. Week of Feb 410 weeks before your last frost

  3. Week of Feb 188 weeks before your last frost

  4. Week of Mar 46 weeks before your last frost

  5. Last frost · Apr 15Tender seedlings such as tomatoes go out after it; onions and the cabbage family a few weeks before.

Seed-starting dates from average frost dates (NOAA 1991–2020 climate normals); watch your local forecast. Made with Grow by Season.

From seed to garden

  • Count back from your last frost

    Each crop starts a set number of weeks before your average last spring frost, so the seedlings are the right size when it is time to plant out.

  • Get them used to the outdoors

    About two weeks before planting out, start setting the young plants outside for a little longer each day, in a sheltered spot, so the sun and wind do not shock them.

  • Plant out on time

    Frost-tender seedlings go out after the last frost. Hardier ones, such as onions and the cabbage family, go out a few weeks before it.

Seed-starting dates by zone

The first day to sow indoors, from each zone's typical last frost. Each date opens a two-week window. In zones 10b to 11b frost is rare, so there is no last frost to count back from.

Show every zone
First day to start seeds indoors in each USDA hardiness zone
ZoneLast frostLeeksOnionsPeppersTomatoesBroccoliBasil
Zone 3aMay 28Mar 5Mar 19Mar 19Apr 2Apr 2Apr 16
Zone 3bMay 17Feb 22Mar 8Mar 8Mar 22Mar 22Apr 5
Zone 4aMay 12Feb 17Mar 3Mar 3Mar 17Mar 17Mar 31
Zone 4bMay 8Feb 13Feb 27Feb 27Mar 13Mar 13Mar 27
Zone 5aMay 3Feb 8Feb 22Feb 22Mar 8Mar 8Mar 22
Zone 5bMay 1Feb 6Feb 20Feb 20Mar 6Mar 6Mar 20
Zone 6aApr 29Feb 4Feb 18Feb 18Mar 4Mar 4Mar 18
Zone 6bApr 23Jan 29Feb 12Feb 12Feb 26Feb 26Mar 12
Zone 7aApr 16Jan 22Feb 5Feb 5Feb 19Feb 19Mar 5
Zone 7bApr 5Jan 11Jan 25Jan 25Feb 8Feb 8Feb 22
Zone 8aMar 29Jan 4Jan 18Jan 18Feb 1Feb 1Feb 15
Zone 8bMar 17Dec 23Jan 6Jan 6Jan 20Jan 20Feb 3
Zone 9aMar 2Dec 8Dec 22Dec 22Jan 5Jan 5Jan 19
Zone 9bFeb 1Nov 9Nov 23Nov 23Dec 14Dec 7Dec 21
Zone 10aJan 24Nov 1Nov 15Nov 23Dec 14Nov 29Dec 21

Questions about starting seeds

When should I start seeds indoors?

Count back from your last spring frost. Leeks and celery need the longest, 10 to 12 weeks. Basil and marigolds grow fast and need only 4 to 6 weeks. Type your ZIP code above for your dates.

Which seeds are better sown outside?

In this calendar, carrots, beets, radishes and other root crops are sown straight in the garden, since their roots do not like being moved, and so are beans, peas, sweet corn, squash and cucumbers. Their dates are on each crop's page.

What if spring runs late this year?

The dates are averages from NOAA 1991–2020 climate normals. If spring runs late, keep the seedlings in their pots a little longer and plant out once the forecast is clear of frost.

The rest of the year

The planting calendar adds sowing outside, planting out and picking for every crop, and the frost dates by state show where your dates come from.