How to Grow Swiss Chard: Planting, Spacing, Care & Harvest

Quick answer

Direct sow about 4 weeks before last frost (UNH) or as early as 0 to 2 weeks before (CSU)n has several embryos (UMD). Days to maturity about 50 to 70 (UMD) or about 60 (CSU).

Swiss chard at a glance

PlantDirect sow: 4 wk before last frost to last frost
SunUMD tolerates partial shade 4–6 hours; best 6–8 hours.
WaterUMD uniformly moist; deep water in dry spells.
SpacingUMD: space seeds 2 inches apart all directions; cover with ½ inch fine soil or 1 inch sandy soil; thin to 4 inches when ~2 inches tall; for larger plants 8–12 inches.
Days to harvest50-70 direct sown (UMD); 60 (CSU)
-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.

Same species as garden beet (Beta vulgaris), grown for leaves. See also beets and spinach for related cool-season greens and rotation notes.

Swiss chard plants with colorful stems in a garden
Swiss chard. Photo: Dietmar Rabich, Wikimedia Commons, CC BY-SA 4.0 (resized).

Planting timing

UMD: semi-hardy (light frost OK; not heavy freeze). “Direct seed into garden in early spring and late summer.” Seeds indoors 5–6 weeks before transplanting; minimize root disturbance. (UMD Extension) UNH: Direct seed 4 weeks before last frost; also lists transplant 2 weeks before last frost. (UNH Extension) CSU: semi-hardy — as early as 0–2 weeks before average last spring frost; typical days to harvest 60. (CSU Extension) UMN: start chard “somewhat later, in early to mid-May” in Minnesota — cold can cause bolting. Fall: sow indoors in June for fall transplants. (UMN Extension)

Depth and spacing

Label each source — they differ. UMD: space seeds 2 inches apart all directions; cover with ½ inch fine soil or 1 inch sandy soil; thin to 4 inches when ~2 inches tall; for larger plants 8–12 inches. Like beet, each “seed” is a fruit with several embryos unless monogerm; thin at 2 inches tall. UMN: seed ¼ to ½ inch deep; rows 18 to 30 inches; thin chard to 4 to 6 inches (closer = baby leaf; farther = larger plants). Transplants same spacing. CSU: spacing 7–9 inches; depth 1 inch; germination 7–10 days.

Sun, soil and water

Sun: UMD tolerates partial shade 4–6 hours; best 6–8 hours. Soil: UMN pH as low as 6 OK for chard; compost/well-rotted manure; no fresh manure; no “Weed and Feed.” Water: UMD uniformly moist; deep water in dry spells. UMN: drought slows new leaves; about one inch per week when raining insufficiently. Mulch / weeds: UMD mulch beside row; hand-remove weed seedlings. UMN shallow cultivate; 3–4 inches mulch; watch lamb’s quarters and pigweed (look like beet/chard seedlings).

Care

Fertilizer: UMD high nutrient need; compost or fertilizer before planting; side-dress as needed — no rates. Bolting: UMD lists bolting as a problem; UMN — summer heat does not bolt chard the way spinach bolts; cold early planting can. Oxalic acid: UMD — all parts contain oxalic acid (same caution class as spinach/beet greens).

Harvest and storage

Days: UMD 50–70 from direct sow. CSU 60. UMD: young leaves (<4 inches) for salads; mature leaves sauté; ribs like celery; harvest until frost; snip leaves 2 inches above crowns to rejuvenate. UMN: pick individual usable leaves; multiple harvests; whole-head harvest also OK; refrigerate a few days. Yield (UMD): 8 to 12 pounds per 10-foot row. Storage: UMD very cold (32°F), moist (95% RH), vented bag in fridge — extremely perishable.

Pests and diseases (organic)

Spinach / beet leafminers: UMD: blotch mines on spinach, beets, Swiss chard; white oblong eggs on undersides — handpick eggs; row cover before egg-laying (April framing); crush/remove mined leaves; remove host weeds (lambsquarters); till top 2 inches in early spring for chronic sites. (UMD leafminers) UMN: leafminers tunnel leaving transparent markings; floating row cover then lightweight mesh in heat.

Cercospora leaf spot: UMD: tan/brown lesions with reddish-purple border; centers may drop out; warm humid weather. Management: 3-year rotation off susceptible crops; remove debris; dense organic mulch; water at base not overhead; pick infected leaves; hot-compost badly infected plants. (UMD Cercospora)

Cutworms, snails/slugs: UMN: cutworms at base; snails/slugs hole leaves — cultural/handpick.

Related: how to grow beets · how to grow spinach · organic pest control · ZIP planner

Frequently asked questions

When do I sow Swiss chard?

Planner last frost −4 to 0 (UNH/CSU). Avoid sowing into hard freezes; UMN warns very early cold can bolt plants.

Why must I thin so hard?

Each seed ball often has several embryos (UMD) — thin early or plants stay crowded and small.

How is chard different from spinach in summer?

Chard does not bolt from long days/heat the way spinach does (UMN); growth slows in drought/heat but resumes when cool/moist.

More grow guides: Asparagus · Peas · Cauliflower · Rhubarb · Leeks · Parsley · Radishes · Eggplant · Arugula · Cilantro · All grow guides

Sources