When to Plant Celery: Cool-Season Timing by Zone

Celery is a cool-season crop with one of the longest growing periods in the vegetable garden.

It needs a long, cool season and is started indoors very early — about 10 to 12 weeks before your last frost — because it grows slowly at first and germinates slowly, too.

It tolerates light frost and can be set out a couple of weeks before the last frost.

The result is a crop that you plant in late winter/early spring indoors and harvest in summer, or plan for a fall crop in warm regions.

Why Celery Needs a Head Start

Celery grows slowly and needs a long cool season. Its tiny seeds germinate slowly (14 to 21 days) and need light and warm soil (70–75°F / 21–24°C).

Because of this slow start, it must be sown indoors 10 to 12 weeks before your average last frost date — earlier than almost any other vegetable.

Sowing too late means stalks that never size up before summer heat, which causes celery to bolt or turn bitter.

Starting Seeds Indoors Early

Start celery seeds indoors 10 to 12 weeks before your last frost date.

Surface-sow the tiny seeds (do not cover deeply; they need light to germinate) and keep the soil moist at about 70–75°F (21–24°C).

Be patient — germination takes 14 to 21 days. Thin seedlings to about 2 inches apart.

Transplant when seedlings are a few inches tall, usually about the time of the last frost or a couple of weeks before.

• 10–12 weeks before last frost: sow celery seeds indoors, surface-sown.
• Keep soil moist at 70–75°F (21–24°C); germination takes 14–21 days.
• Transplant: when seedlings are a few inches tall, near the last frost date.

Zone-by-Zone Planting Windows

The table below shows representative sow-indoors and transplant windows by USDA hardiness zone, based on published average last-frost dates.

Coastal and mild regions allow earlier starts; cold inland valleys are later.

Confirm your exact dates with your county extension office or the Almanac frost-date lookup.

• Zones 3–4 (last frost mid-May to early June): sow indoors late February to March; transplant mid-to-late May.
• Zone 5 (last frost early to mid-May): sow indoors mid-to-late February; transplant early-to-mid May.
• Zone 6 (last frost mid-April): sow indoors early-to-mid February; transplant mid-to-late April.
• Zone 7 (last frost late March): sow indoors late January to early February; transplant late March.
• Zone 8 (last frost mid-February to early March): sow indoors early January; transplant late February.
• Zone 9 (last frost mid-January to early February): sow indoors early January; transplant February.
• Zone 10 (no hard frost): sow late summer/fall for a winter crop.

Transplanting Outdoors Correctly

Celery tolerates light frost and can go out a couple of weeks before the last frost, but it dislikes hard freezes.

Set transplants out when seedlings are a few inches tall and night temperatures stay above about 50°F (10°C).

Plant in fertile, moisture-retentive soil in full sun, spacing plants about 8 inches apart.

Keep the soil consistently moist — celery is very sensitive to drought and dry spells cause stringy stalks and bitter flavor.

Soil and Season Considerations

Celery is a cool-season crop that grows best in 60–70°F (15–21°C) conditions and dislikes heat above about 80°F (27°C), which triggers bolting.

It needs rich, moisture-retentive soil and steady water.

In warm regions, grow celery as a fall or winter crop to avoid summer heat, sowing in late summer.

In cool regions, a spring planting matures in early summer before the worst heat.

Signs You Planted Too Early or Too Late

Planted too early — before the soil is workable or into a hard-freeze window — celery sits stunted.

Planted too late in the season, it bolts and turns bitter in summer heat before stalks size up.

The fix: start seeds early indoors (10–12 weeks ahead), transplant near the last frost, keep soil consistently moist, and in warm regions plan a fall crop.

Related Guides

• How to Grow Celery
• How to Start a Vegetable Garden
• When to Plant Lettuce

FAQ

1. 1

   What month is best to plant celery?

   Celery is started indoors very early — 10 to 12 weeks before your last frost — so the sowing month depends on your zone (often late winter/early spring). It is transplanted near the last frost date. In warm regions, a fall planting is often better.

2. 2

   Can celery tolerate frost?

   Yes, celery tolerates light frost and can be set out a couple of weeks before the last frost, but it dislikes hard freezes. Keep it protected if a hard freeze is forecast.

3. 3

   How many weeks before last frost do I start celery seeds indoors?

   About 10 to 12 weeks before your average last frost date. Celery grows and germinates slowly, so it needs a much earlier start than most vegetables.

4. 4

   Why does my celery bolt and turn bitter?

   Bolting is triggered by hot weather — usually above about 80°F (27°C) — and long days. Plant early enough, choose slow-bolting varieties, keep the soil moist, and in warm regions grow a fall crop.

5. 5

   Can I grow celery in warm climates?

   Yes, grow it as a fall or winter crop. Sow in late summer so it matures in the cooler months, avoiding the summer heat that causes bolting.