How to Grow Celery: Planting, Spacing, Care & Harvest

Quick answer

Start indoors 10–12 weeks before set-out (UNH; UMD). Transplant after last frost / when frost risk is past. Usable size about 85–100 days from transplanting (UMD). Extended nights below about 55°F can cause bolting (UMD).

Celery at a glance

PlantStart indoors: 12–10 wk before last frost; Transplant: last frost
SpacingUMD commercial guidance: rows 16–32 inches apart; plants about 8 inches in the row — home gardens can use the same order of magnitude.
Days to harvest85–100 days from transplanting (UMD commercial guide)
-13-12-11-10-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.

Organic pests and diseases: see also organic pest control. Use any product as the label directs.

Celery (Apium graveolens var. dulce) — cool-season transplant crop.

Celery plants
Celery. Photo: Robert Kerton / CSIRO, Wikimedia Commons, CC BY 3.0 (resized).

Planting timing

UNH celery (T): time from seed to transplant 10–12 weeks; safe to set out after last frost. (UNH when to plant) UMD: “Sow seed 10–12 weeks before field planting.” “Plants for an early crop should be set in the field when there is no more risk of frost or a cold period.” Do not harden by chilling — withhold water 7–10 days instead; keep night greenhouse temperatures above 55°F to avoid seeders. (UMD Celery PDF) Planner: Start indoors last frost −12 to −10; Transplant last frost 0.

Depth and spacing

UMD commercial guidance: rows 16–32 inches apart; plants about 8 inches in the row — home gardens can use the same order of magnitude.

Sun, soil and water

Cool-season crop; best about 55–75°F; steady moisture and high organic matter; well drained or root rot risk (NC State). (NC State celery) UMD: light freezes are tolerated; moderate freezes damage plants; days below 55°F can trigger bolting. Prefer compost-rich moist soil; we omit commercial N rates.

Care

Blanching is optional for non-self-blanching types (UMD). Keep moisture even.

Harvest

UMD: usable size about 85–100 days from transplanting.

Pests and diseases

NC State: aphids, earwigs, nematodes, celery worms, slugs; root rot if poorly drained. UMD: green peach aphids; Cercospora/Septoria blights — use pathogen-free or hot-water-treated seed, sanitation, and a 3–4 year rotation. Aphids: insecticidal soap or oil with thorough coverage as labeled (UC IPM).

Related: ZIP planner · organic pest control · all grow guides · celeriac · lovage

Frequently asked questions

When do I start celery indoors?

10–12 weeks before transplanting; set out after last frost (UNH; UMD).

Why did my celery bolt?

Extended cool temperatures below about 55°F (UMD).

How long to harvest?

About 85–100 days from transplanting (UMD).

More grow guides: All grow guides

Sources