How to Grow Swiss Chard

Swiss chard is a beet that was selected for its leaves and stalks instead of a swollen root (Maryland Extension). It’s one of the most forgiving greens. UW-Madison says it grows well regardless of soil type, day length or temperature, tolerates heat better than spinach and rarely bolts. One spring sowing can keep you in greens until hard frost, which makes chard the summer stand-in for spinach in hot regions.

When to plant

Sow chard outdoors 2 to 4 weeks before the last spring frost. Utah State says 2 to 3 weeks, and UW-Madison says about a month. UW-Madison adds that you can keep sowing through midsummer. For an earlier start, grow transplants indoors for 5 to 6 weeks (Utah State, Maryland) and set them out near the last frost. Maryland advises disturbing the roots as little as possible. Use the dates for your zone above.

Sources disagree on soil temperature. Utah State says chard can be sown at 40°F and germinates best at 55 to 75°F, emerging in 7 to 14 days. UW-Madison’s chart lists a 55°F minimum and an 85°F optimum. In practice, early sowings in cold soil come up slowly. Utah State notes germination drops when the soil is above 80°F.

Fall timing is less clear. Utah State’s main fact sheet times fall chard to mature 2 to 3 weeks before the first frost, sown 50 to 75 days before that, which works out to about 9 to 13 weeks before frost. Its own FAQ gives a much later 3 to 4 weeks before frost. The earlier timing lets plants reach full size first, and since chard keeps growing through light frosts, you can go on picking into early winter. In the Pacific Northwest, WSU Extension in Skagit County reseeds chard in July or August for a long winter harvest.

In warm-winter areas (Florida, the Gulf Coast, south Texas and the Arizona low desert), chard has a long season from late summer or fall through winter and spring. The months are in the dates for your zone above.

Sowing and thinning

Plant seed 1/2 inch deep (Utah State, Maryland). UW-Madison says 1 inch, Illinois says 1/2 to 3/4 inch, and Maryland suggests going to 1 inch in sandy soil. Each “seed” is a seed ball with several embryos (Maryland), so seedlings come up in small clumps. Thin them when they’re about 2 inches tall, unless the packet says monogerm.

Final spacing varies by source and by how big you want the plants. Utah State uses 6 inches in rows 12 inches apart. Maryland and Illinois go to 8 to 12 inches for larger plants, and UW-Madison to about a foot. Illinois suggests thinning first to 2 to 3 inches. Then, when plants are 6 to 8 inches tall, pull every other one for greens, leaving 9 to 12 inches between the rest. UW-Madison notes crowded chard doesn’t fail: it just makes more, smaller leaves.

Water, feeding and weeds

Give chard about 1 to 2 inches of water a week (Utah State). It tolerates some dryness but produces best when the soil stays evenly moist (UW-Madison), and moisture swings make leaves tough and off-flavored. Utah State sidedresses with 1/4 cup of 21-0-0 per 10 feet of row about 4 weeks after transplanting or thinning. Maryland calls chard a crop with high nutrient needs and recommends working in compost or fertilizer before planting.

Young chard competes poorly with weeds (Utah State). Pull weed seedlings by hand and mulch along the rows with straw or grass clippings. Mulch also cools the soil and saves water.

Regional notes

In the North, chard carries the harvest from early summer into fall. UW-Madison says a cold frame usually keeps it going well into December in southern Wisconsin. In the Pacific Northwest, WSU Extension says chard has few pests or diseases. In the humid South and Florida, heat is less of a problem than root-knot nematodes. UF/IFAS calls chard very susceptible to them. In the arid West, Utah State recommends mulch to save water and cool the soil, and notes that high summer temperatures slow growth and can make leaves bitter.

Extension services recommend these varieties for their states:

• Utah (Utah State): ‘Rhubarb’, ‘Bright Lights’, ‘Lucullus’, ‘Fordhook Giant’.
• Florida (UF/IFAS): ‘Bright Lights’, ‘Bright Yellow’, ‘Fordhook Giant’, ‘Lucullus’, ‘Red Ruby’.
• Texas (Texas A&M): ‘Bright Lights’, ‘Lucullus’, ‘Ruby’. For the Lower Rio Grande Valley, Texas A&M also lists ‘Rhubarb’, ‘Fordhook’, ‘Red Magic’ and ‘Red Winter’.

UW-Madison describes ‘Bright Lights’, a 1998 All-America Selections winner with stalks from white to red, as good enough for flower beds. It suggests pairing chard with low annuals such as petunias or dianthus. That is a design idea, not a companion-planting benefit.

Problems

• Leafminers. Larvae tunnel inside the leaves. Pick off and discard mined leaves. UW-Madison notes the weed lamb’s-quarters hosts the same pest, so pull it from around the garden.
• Aphids. Hose them off, use insecticidal soap, or let lady beetles, lacewing larvae and syrphid fly larvae handle them (UW-Madison).
• Root-knot nematodes. They cause galls on the roots, stunting and wilting. Maryland has documented them on chard in Baltimore. Rotate crops and add organic matter where they’re a problem.
• Cercospora leaf spot. A fungal spotting of the leaves (Maryland). Remove affected leaves and rotate the bed each year.
• Slugs and flea beetles. Slugs chew holes in damp conditions, and flea beetles riddle seedlings. Utah State recommends traps for slugs and floating row cover for flea beetles.
• Bolting. It’s uncommon. Pull any plant that sends up a seed stalk (UW-Madison).

Harvest and storage

Young leaves about 3 inches long are ready roughly 4 weeks after planting and are tender enough for salads (UW-Madison). For cooking greens, cut outer leaves near the base once they reach about 8 to 12 inches (Illinois) or 8 to 10 inches (UF/IFAS). Never damage the growing point at the center. Alternatively, cut the whole plant about 2 inches above the crown (Maryland, Utah State), or 3 inches according to UW-Madison, and it will regrow. UW-Madison puts the first whole-bunch harvest at about 2 months after planting. It advises picking early or late in the day, because leaves wilt fast in hot sun.

If leaves turn bitter in midsummer, keep removing the older ones. New growth gets milder as the weather cools. Utah State and Maryland both estimate 8 to 12 pounds from a 10-foot row, so a few plants feed a household. Storage advice differs: Utah State and UW-Madison say 1 to 2 weeks in the refrigerator, while Illinois says to use the leaves within 2 to 3 days. Store leaves unwashed in a bag. Maryland notes all parts of the plant contain oxalic acid.