CULTURE:Soil pH should be over 6.0. Cool and mild weather is preferred, though chard has some heat tolerance. Seeds germinate in soil temperatures from 40–100°F (5–38°C) with an optimum of 86°F (30°C). Seedlings will tolerate light frosts, and mature plants will tolerate moderate frosts. Swiss chard may overwinter in mild areas.
TRANSPLANTING:Sow seed in a cold frame or indoors in early spring, about 5–6 weeks before transplanting out after heavy frosts become infrequent. Sow 1/2" deep, 2–3 seeds per cell in 72- or 128-cell flats. Thin to 2–3 plants per cell. Transplant out 4" apart in rows 12–18" apart.
DIRECT SEEDING:Bunching: Sow about 6 seeds/ft., 1/2" deep, rows 18–24" apart from midspring and on into midsummer (fall where winter is mild). Thin to 4–6" apart for larger leaves. Baby Leaf: Sow 1/4– 1/2" deep at 1–2 seeds/inch in rows at least 2" apart from midspring into late summer (fall where winter is mild). Planting too densely can lead to overcrowding and stunted growth. When planting more seeds per inch, be sure to plant rows farther apart.
HARVEST:Bunching: Cut or snap mature leaves individually. New leaves will grow for multiple harvests. Baby Leaf: Harvest with a knife when leaves reach desired size, about 3–6". Cut about an inch above the soil to allow for clean regrowth, making sure to cut above the basal plate. Cut again when leaves reach desired size (5–14 days, depending on variety).