Swiss Chard Plant Guide: How to Grow Swiss Chard from Spring to Winter

To grow a swiss chard plant, sow seed 1/2 inch deep once the soil reaches 40 F, from about 4 to 2 weeks before your last spring frost (our span of Utah State's two figures), plus a second sowing in mid or late summer for fall. Each seed is a cluster that sends up several seedlings, so thin to 4 to 12 inches apart. Start picking outer leaves in roughly 40 to 75 days and keep picking through the season. Chard shrugs off light frost: Oregon State puts it at 28 to 32 F, and Mississippi State says mature plants handle the upper 20s. Where winters stay mild, it can stand through to spring.

When to plant swiss chard

Chard is a cool-season green that goes out early, before the last spring frost, and then again in summer for fall. Utah State Extension is the only extension source here that ties sowing to the frost date in weeks. Its planting section puts transplants out near the last frost date and lets direct-seeded chard go in 3 to 4 weeks sooner; its FAQ says 2 to 3 weeks before the last frost. Either way, it wants the soil at 40 F or warmer first. The University of Maryland sows in early spring and again in late summer, and starts seedlings indoors 5 to 6 weeks ahead of setting them out. The seed company Kitchen Garden Seeds gives two answers: its growing notes sow when the soil passes 45 F, roughly 2 weeks ahead of the final frost, while its product text waits until all threat of frost has passed and the soil is about 50 F.

Below, those rules become calendar dates at four of NOAA's weather stations. A station's freeze date is its 32 F normal for 1991 to 2020; a frost is equally likely before or after it.

Swiss chard planting dates at four NOAA stations

Station	Indoor start (Utah State, Maryland)	Direct sowing (Utah State)	Spring freeze date	Fall-crop sowing (Utah State)	Fall freeze date
Minneapolis-St. Paul, MN	Mar 12 to Mar 19	Mar 26 to Apr 9	Apr 23	Jul 14 to Aug 15	Oct 18
Baltimore (BWI), MD	Feb 27 to Mar 6	Mar 13 to Mar 27	Apr 10	Jul 27 to Aug 28	Oct 31
Raleigh-Durham, NC	Feb 17 to Feb 24	Mar 3 to Mar 17	Mar 31	Jul 31 to Sep 1	Nov 4
Dallas-Fort Worth, TX	Jan 25 to Feb 1	Feb 8 to Feb 22	Mar 8	Aug 20 to Sep 21	Nov 24

Our arithmetic, not a source's dates. Direct sowing = 4 to 2 weeks before the spring freeze date, spanning Utah State's two figures, and only once the soil is at 40 F, which in a cold spring comes later. Indoor start: 6 to 5 weeks ahead of it, our reading of Utah State's "near the last frost-free date" for transplants as that date itself. Fall-crop sowing = 96 to 64 days before the fall freeze date: Utah State sows early types 50 to 75 days before they should mature and wants them ready about 2 to 3 weeks ahead of the first fall frost, so we added the two. Its FAQ gives a shorter lead, 3 to 4 weeks before that frost.

Southern and mild-winter calendars. Where frost is light, the season runs the other way round. UF/IFAS plants chard from September to May in North and Central Florida, and from September to March in South Florida. Alabama Extension sows from mid-February to mid-March for a spring crop and in September for fall. Mississippi State grows it through fall, winter and well into spring. Use the NOAA station closest to you; a USDA hardiness zone does not give a frost date.

Which swiss chard planting fits your season

Soil temperature and the next freeze settle it. Answer each question in turn.

Swiss chard cold tolerance: how cold is too cold

Swiss chard handles light frost, roughly 28 to 32 F, but not a hard freeze. Oregon State Extension files chard with the semi-hardy crops that take light frost of 28 to 32 F; its list for heavy frost below 28 F leaves chard out. Mississippi State says mature plants can go down to the upper 20s, more so under mulch or a light frost cloth. Utah State says 32 F does no serious harm to young plants, and that chard can stay in the garden after light frosts. Our rule from those figures: before a night below about 28 F, pick the leaves you want, then mulch or cover the plants you mean to keep; Mississippi State credits mulch or a light frost cloth for the upper 20s, and Utah State uses fabric covers to shield seedlings and transplants from frost.

The other sources say the same thing in words rather than degrees:

• University of Maryland: semi-hardy. It survives light frosts but not heavy frost or a freeze, and the roots take more cold than the leaves.
• Johnny's Selected Seeds (seed company): seedlings take light frosts, mature plants moderate ones. It also notes that its 'Bright Lights' mix is a little less frost-hardy than other chard.
• University of Georgia: chard tolerates mild freezes.

Our reading of those figures: below about 28 F, expect damaged leaves; the crown and roots may still pull through, as Maryland's note on roots suggests. None of the sources gives a figure below the upper 20s, so we do not either.

Cold has a second effect: bolting. Chard is a biennial (Maryland), and cold can push it to flower early. Johnny's warns that some varieties feel pressure to bolt when seedlings sit for a long time in the low 50s or colder, and Kitchen Garden Seeds says chard planted in soil that is too cold goes straight to seed. That is one more reason to wait for 40 F soil, or 45 F by the seed company's figure, before a spring sowing.

Overwintering swiss chard

Chard can come through winter where winters are mild, as Johnny's puts it, and the southern sources treat winter as part of its main season (see the calendars above). Our reading for colder areas: an established plant can stand through frosts into the upper 20s; colder than that, expect losses.

What to expect from a plant that lives through winter:

• It will flower in spring. The Texas A&M farm sheet says long days of 14 hours or more after a cold spell trigger bolting. Pick the new spring leaves while you can; the University of Georgia keeps harvesting until the plants bolt and flower.
• One variety is meant for the cellar. The University of Georgia lists 'Winter King' as one to dig in fall and keep cool and moist for winter picking indoors.

Oregon State's vegetable breeder calls winter gardening risky: it can pay in a mild winter and fail in a harsh one. Treat overwintered chard as a bonus.

Sowing swiss chard: one seed, several seedlings

A chard "seed" is really a small fruit, or seed ball, holding several embryos, the same as beet seed (Maryland). Unless the packet says monogerm, expect a clump of seedlings from each one. Thinning happens in two stages.

First, the clump. Maryland thins when seedlings are 2 inches tall, Utah State at 3 to 4 true leaves, and Kitchen Garden Seeds at about 3 inches tall. Maryland thins by cutting plants out, and Utah State says thinnings lifted with some roots can be replanted nearby, or eaten. Our reading: keep the strongest seedling at each spot.

Then, final spacing. The sources run from 4 to 12 inches apart (table below). Our reading: close for baby leaves, wide for big plants picked over months.

Depth, germination, transplants. Sources that give a depth sow 1/4 to 1/2 inch; Kitchen Garden Seeds soaks the seed for an hour in warm water first. Germination ranges differ widely: 55 to 75 F (Utah State), 40 to 100 F (Johnny's), 45 to 65 F (Kitchen Garden Seeds). Transplants generally take 5 to 6 weeks to grow by Utah State's and Johnny's count, 3 to 4 by Alabama's; Maryland warns against disturbing the roots.

In containers. Alabama fits 4 to 6 plants in a 5-gallon container of potting mix with drainage holes. UF/IFAS suggests a planter or grow bucket where garden soil is heavily infested with root-knot nematodes, and Johnny's notes that chard is popular in mixed ornamental containers.

The sources compared side by side:

How the swiss chard sources compare

Who says it	Depth	Final spacing	Soil temperature	Days to harvest	Cold limit
Utah State	1/2 in	6 in; rows 12 in	Sow at 40 F; sprouts at 55 to 75 F	Not given	32 F no serious harm to young plants
U. of Maryland	1/2 in (1 in sandy soil)	4 in, or 8 to 12 in for larger plants	Not given	50 to 70	Light frost, not heavy frost
UF/IFAS	Not given	6 to 12 in	Not given	40 to 60	Not given (plants Sep to May)
Alabama	1/2 in	4 to 6 in	Not given	50 to 75	Not given
U. of Georgia	1/2 in	4 to 6 in	Sow when soil is workable	Usually 4 to 6 weeks; varieties 40 to 45	Mild freezes
Oregon State	Not given	Not given	Not given	Not given	Light frost, 28 to 32 F
Mississippi State	Not given	Not given	Not given	Not given	Mature plants to the upper 20s; thrives at 40 to 75 F
Texas A&M (farm sheet)	0.25 to 0.5 in	6 to 12 in	Seed zone under 100 F	50 to 60	Not given; prefers nights of 40 to 45 F
Johnny's (seed company)	1/2 in	4 to 6 in; rows 12 to 18 in	40 to 100 F; optimum 86 F	55 ('Bright Lights')	Mature plants: moderate frosts
Kitchen Garden Seeds (seed company)	1/4 to 1/2 in	10 to 12 in; rows 16 to 20 in	Over 45 F; sprouts at 45 to 65 F	60 ('Argentata')	Leaves keep coming through a light frost

Growing swiss chard through summer

Chard handles summer heat better than most leafy greens. UF/IFAS calls it "more heat tolerant than spinach or lettuce", and Johnny's says one sowing gives greens all season. Heat still costs it something. Utah State says chard does its strongest growing while temperatures top out at 75 F, and that hot summer weather slows it down and may make the leaves bitter. The Texas A&M farm sheet says air above 80 F thins the leaves and dulls their color.

• Water steadily. Utah State and Alabama give 1 to 2 inches a week; Georgia gives about 1 inch. Utah State warns that swings in soil moisture toughen the leaves and spoil the flavor.
• Mulch. Utah State lays straw, grass clippings or newspaper to cool the soil as the weather warms; Georgia mulches with straw, wood chips or weed-free grass clippings, taking clippings only from a lawn not treated with herbicide.
• Feed after thinning. Utah State side-dresses with a nitrogen fertilizer 4 weeks after thinning or transplanting; Alabama side-dresses 4 weeks after sowing. Both start from a soil test where one is available.

Harvesting swiss chard: cut and come again

Pick the outer leaves and leave the center growing, the method every source here describes. UF/IFAS takes a few outer leaves at a time for a long harvest, Georgia picks the largest outside leaves, and Mississippi State calls chard a cut-and-come-again crop. Johnny's cuts or snaps mature leaves one at a time and lets new ones grow back.

• When. UF/IFAS starts at 40 to 60 days after seeding, or when leaves are 8 to 10 inches long; Alabama picks leaves about 8 inches long at 50 to 75 days; Georgia waits for leaves about 12 inches long, usually 4 to 6 weeks after planting.
• A harder cut. Utah State says you can take every leaf down to 2 inches above the soil, provided the growing point is unharmed. Maryland snips leaves 2 inches above the crown at any point in the season to refresh a plant.
• Baby leaves. Johnny's harvests baby leaf at 3 to 6 inches, cutting roughly an inch up so the cut sits above the plant's base, then cuts the regrowth 5 to 14 days on. Maryland uses leaves under 4 inches raw in salads.
• Keeping it. Maryland calls chard extremely perishable and stores it near 32 F in a vented bag in the refrigerator; Utah State gives it 1 to 2 weeks refrigerated.

Swiss chard varieties: Argentata, Bright Lights and rainbow mixes

Chard comes in white-stemmed, red-stemmed and mixed-color types. Here is what the sources and seed listings say about the names you will see most:

• 'Argentata', a silver-ribbed chard. Fedco Seeds lists it at 55 days, with wide silvery-white midribs, deep green savoyed leaves, and plants 2 to 3 feet tall that it says cope with a wide range of weather. Kitchen Garden Seeds gives 60 days, lists it also as 'Bionda Costa', and says Italian cooks prize it. NE Seed sells a strain called 'Verde a Costa Larga Argentata 2' at 55 days and describes it as slow bolting.
• 'Bright Lights', a multicolor mix. Johnny's lists stems in many colors, among them gold, pink, orange, red and white, 55 days to a bunching harvest, strong bolt resistance across the colors, and slightly less frost hardiness than other chard. Georgia gives it 40 days and Fedco 56. Utah State, UF/IFAS and the Texas A&M sheet all name it.
• "Rainbow chard" is how mixes are sold rather than one variety: UF/IFAS says mixes of several chard varieties are marketed that way, and Maryland lists 'Rainbow Chard' among its red-ribbed forms.

Green, white-stemmed standards include 'Fordhook Giant' and 'Lucullus', and red-stemmed ones 'Rhubarb' and 'Ruby'; Utah State, Maryland, UF/IFAS, Georgia and Texas A&M name these between them. Listings differ on days for the same name ('Argentata' 55 or 60, 'Bright Lights' 40, 55 or 56), so treat them as rough guides. Chard and beets are one species, Beta vulgaris; chard is simply the form grown for leaves rather than a swollen root (Maryland, UF/IFAS).

What to plant with swiss chard

In our reading, no companion planting page we checked names a pest or shade partner for chard. UF/IFAS grows it as an ornamental among flowers, in beds or containers; Alabama Extension uses it in borders; and Maryland sows chard once spring peas finish. Vegetable pairings are in our companion planting chart.

Swiss chard pests: leafminers and others

Leafminers. The University of Maryland names the spinach and beet leafminers (Pegomya hyoscyami and P. betae) as pests that feed chiefly on spinach, beets and chard. The larvae tunnel inside the leaf and leave pale tunnels or blotches just under the surface. Maryland's controls:

• Check leaf undersides for the small white eggs and pick them off.
• Squeeze mined leaves between your fingers to kill the larvae, or pick those leaves off.
• Put row cover over the bed before the flies lay eggs.
• Pull nearby host weeds such as lambsquarters, and skip insecticides, which hold back the many parasitic insects that attack leafminers.

Georgia also says leaf miners can be a problem and covers plants with cheesecloth or row cover to keep them out.

Other pests. Utah State lists aphids, slugs and flea beetles. A strong spray of water knocks aphids off; flea beetles chew small holes in seedlings and can be kept off with floating row cover.

Diseases and roots. Johnny's uses crop rotation against Cercospora leaf spot, and Utah State says rotation controls most chard diseases. UF/IFAS warns that root-knot nematodes hit chard hard; if plants grow slowly, check their roots.

Deer. The sources disagree. Georgia says chard is not deer tolerant and that deer eat it mostly in fall; Kitchen Garden Seeds lists it as deer resistant. Plan for Georgia's answer if deer visit your garden.

Seeds and supplies

For broad white stems, 'Argentata'; for color, 'Bright Lights'; for a plain green chard, 'Fordhook Giant' or 'Lucullus' (see the varieties above). Beyond seed: row cover against leafminers and flea beetles, and snips or a sharp knife for harvest.

What you'll need for Swiss chard

As an Amazon Associate we earn from qualifying purchases.

• 

  Park Seed Bright Lights Swiss Chard Seeds

  A multicolor mix; Johnny's notes it is a little less frost-hardy than other chard.

  Check price on Amazon
• 

  Hometown Seeds Lucullus Swiss Chard Seeds

  A green, white-stemmed standard.

  Check price on Amazon
• 

  Corona FS 3214D ComfortGEL Micro Snips

  Snips or a sharp knife for harvest.

  Check price on Amazon

Sources we used

Figures appear as each source states them, and where sources disagree we show both.

• "Utah State University Extension: How to Grow Swiss Chard in Your Garden"
• "University of Maryland Extension: Growing Swiss Chard in a Home Garden" and "Leafminers on Vegetables"
• "UF/IFAS Gardening Solutions: Swiss Chard"
• "Alabama Cooperative Extension System: Grow More Swiss Chard"
• "University of Georgia Extension: Home Garden Swiss Chard"
• "Oregon State University Extension: Plant cold-hardy vegetables now for a spring harvest"
• "Mississippi State University Extension: Chard, broccoli, kale thrive in winter gardens"
• "Texas A&M AgriLife Extension: Swiss chard fact sheet"
• Companion pairs: "University of Maryland Extension: Vegetable Succession and Companion Planting"
• "Johnny's Selected Seeds: Swiss Chard Key Growing Information", plus its 'Bright Lights' listing (seed company)
• 'Argentata' listings from three seed companies: Fedco Seeds, Kitchen Garden Seeds and NE Seed
• "NOAA NCEI: U.S. Climate Normals, 1991-2020", the input to our frost table

Related guides

• How to grow strawberries, including day-neutral plants for a patio pot
• How to grow chicory, more leaves to pick through fall
• How to grow arugula, a fast cool-weather green that fits beside chard
• How to grow turnips and rutabagas, another crop sown in summer for fall
• How to grow kale, a tougher green for the same winter bed
• How to grow cilantro, a cool-weather herb for the spring and fall sowings
• How to protect plants from frost, covers on before sunset and off in the morning
• Frost covers we picked, with hoops and fleece covers too
• Grow bags buying guide, fabric pots and the container sizes extension services give by crop

Frequently asked questions

How cold can swiss chard tolerate?

Light frost of about 28 to 32 F, by Oregon State's figure; Mississippi State says mature plants handle the upper 20s, especially under mulch or frost cloth. Our reading: below that, expect damaged leaves.

When should I plant swiss chard?

In spring, about 2 to 4 weeks before the final spring frost once the soil reaches 40 F (Utah State), with a second sowing in mid or late summer for fall. In Florida, UF/IFAS plants from September into spring.

How do you harvest swiss chard so it keeps growing?

Take a few outer leaves at a time and let the center keep growing. Utah State says you can cut all the leaves to 2 inches above the soil if the growing point is not harmed.

Why do several seedlings come up from one swiss chard seed?

Each seed is a small fruit holding several embryos, like beet seed (Maryland), so unless you sowed monogerm seed, Maryland thins once seedlings are about 2 inches tall. Our reading: keep one strong seedling per spot, then space plants 4 to 12 inches apart.

Does swiss chard come back every year?

No. It is a biennial grown as an annual. Where winters are mild it can live through to spring, but in its second season it flowers and sets seed.

How far apart should swiss chard plants be?

Final spacing in the sources runs from 4 to 12 inches. Use the close end for baby leaves and the wide end for large plants picked over a long season.

Can you grow swiss chard in summer?

Yes, better than most greens: UF/IFAS calls it "more heat tolerant than spinach or lettuce". Utah State notes growth slows and leaves can turn bitter in high heat, so water steadily and mulch.

Are swiss chard and beets the same plant?

They are the same species, Beta vulgaris. Chard has been bred for its leaves and stems rather than a swollen root.