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When to Start Lettuce Seeds

Dates to start lettuce indoors, harden off and plant out for your ZIP code or zone.

Tomato and pepper seedlings in trays under an LED grow light

Lettuce planting dates by zone

At the average last frost date for each USDA half-zone (the median across its ZIP codes, NOAA 1991 to 2020 normals). Enter your ZIP code below for your own dates.

ZoneLast frostStart indoorsTransplantSow outdoors
3aMay 28Apr 16 to Apr 23May 28May 7 to May 14
3bMay 17Apr 5 to Apr 12May 17Apr 26 to May 3
4aMay 13Apr 1 to Apr 8May 13Apr 22 to Apr 29
4bMay 8Mar 27 to Apr 3May 8Apr 17 to Apr 24
5aMay 4Mar 23 to Mar 30May 4Apr 13 to Apr 20
5bMay 1Mar 20 to Mar 27May 1Apr 10 to Apr 17
6aApr 29Mar 18 to Mar 25Apr 29Apr 8 to Apr 15
6bApr 23Mar 12 to Mar 19Apr 23Apr 2 to Apr 9
7aApr 16Mar 5 to Mar 12Apr 16Mar 26 to Apr 2
7bApr 6Feb 23 to Mar 2Apr 6Mar 16 to Mar 23
8aMar 29Feb 15 to Feb 22Mar 29Mar 8 to Mar 15
8bMar 18Feb 4 to Feb 11Mar 18Feb 25 to Mar 4
9aMar 3Jan 20 to Jan 27Mar 3Feb 10 to Feb 17
9bFeb 2Dec 22 to Dec 29Feb 2Jan 12 to Jan 19
10aJan 16Dec 5 to Dec 12Jan 16Dec 26 to Jan 2
10brareby seasonby seasonby season
Your location

Zone medians. Your ZIP code gives the dates of your nearest weather station.

Frost risk

Half of years still get a frost after the spring date, and half get the first fall frost before the fall date.

Frost dates at three risk levels
AverageSaferSafest
Last spring frostApr 23Apr 30May 9
First fall frostOct 22Oct 16Oct 7
Crops (1 selected)

Start your first seeds indoors

Mar 12lettuce

Average frost dates: last Apr 23, first Oct 22 (zone 6b).
Season
Spring seed starting schedule
CropStart indoorsHarden offTransplantSow outdoorsNotes
LettuceHardyMar 12 to Mar 19Apr 2 to Apr 22Apr 23Apr 2 to Apr 9Indoors 5 to 6 wk before last frost. Transplant at last frost. Sow outdoors 2 to 3 wk before last frost. Sprouts in 4 to 10 days, best at 40 to 80°F soil. Pot up at the first true leaves.

How to start seeds indoors

Light
Give seedlings 14 to 18 hours of light a day on a timer, with fluorescent or LED fixtures 2 to 6 in above the leaves. Raise the lights as the plants grow.
Clemson HGIC: 16 to 18 hours, tubes 2 to 4 in above. UMD Extension: 14 to 16 hours, 2 to 6 in.
Seed starting mix
Use a sterile, soilless mix, never garden soil. To mix your own, combine equal parts by volume of fine pine bark, sphagnum peat moss and perlite.
NC State Extension Gardener Handbook; Clemson HGIC.
Sowing and warmth
Sow two or three seeds per cell and keep the strongest seedling. A mix temperature of 65 to 75°F germinates most vegetables; after they sprout, 55 to 60°F nights and 65 to 70°F days keep them stocky.
UMD Extension.
Potting up
Move seedlings into larger pots shortly after the first true leaves appear, while they are small and recover quickly.
UMD Extension; Clemson HGIC (one or two sets of true leaves).
Hardening off
Start two to three weeks before transplanting, once plants are about 3 in tall: set them outdoors by day, bring them in before sundown, and give them more direct sun each day. Skip days below 45°F or with strong wind.
Clemson HGIC: 2 to 3 weeks. NC State: at least 2 weeks, not below 45°F.

When to start lettuce seeds

Lettuce gives you two ways in, and both start early. Utah State University Extension sows lettuce outdoors 2 to 3 weeks before the last spring frost, or grows transplants for 5 to 6 weeks indoors and sets them out near the last frost date. The table above shows both for every USDA zone; the planner below it works them out for your ZIP code.

Start indoors = last frost − 6 to 5 weeks · Sow outdoors = last frost − 3 to 2 weeks

Example dates by zone

At the median last frost for each half-zone (NOAA 1991 to 2020 normals):

ZoneAverage last frostStart indoorsTransplantSow outdoors
5bMay 1Mar 20 to Mar 27May 1Apr 10 to Apr 17
7aApr 16Mar 5 to Mar 12Apr 16Mar 26 to Apr 2
9aMar 3Jan 20 to Jan 27Mar 3Feb 10 to Feb 17

The two routes reach the garden about two weeks apart, but transplants arrive as plants 5 to 6 weeks old, so they are ready to pick sooner. In the planner the hardening off window runs in the three weeks before transplanting: Apr 10 to Apr 30 in zone 5b.

Why lettuce goes in before the frost

Lettuce is rated hardy, and its seed sprouts in cold soil: Oregon State University Extension lists a minimum of 35°F, and Utah State says it germinates best at 55 to 65°F, with poor germination above 80°F. Utah State adds that lettuce grows best when temperatures stay under 75°F, and that heat and water stress make it bitter. Planting early lets the crop finish before summer heat.

Direct sow or transplant?

  • Sow outdoors needs no lights or pots, and you can sow again every 2 to 3 weeks, the interval Johnny's Selected Seeds uses for a steady supply of leaves or heads.
  • Start indoors and the plants go out already 5 to 6 weeks old. Lettuce takes about 60 days from seed (Colorado State University Extension), so transplants spend only a few weeks in the bed before the first harvest.

Sow seed ¼ to ½ inch deep either way. Utah State says seedlings emerge in 7 to 10 days at good temperatures.

Next questions

  • How far apart? Leaf lettuce 7 to 9 inches in a bed or 4 per square foot, head lettuce 8 to 12 inches; the lettuce spacing calculator counts plants for your bed.
  • How much to plant? Utah State plans 5 to 10 ft of row per person; see lettuce per person.
  • Later sowings? The succession planting planner sets the dates for repeat sowings from your frost dates.