key growing information

Growing Swiss Chard From Seed

How to grow Swiss chard: soil, temperature and bolting, pelleted seed, transplants, direct sowing for bunching or baby leaf, seeding rates, disease, harvest and seed processing.

By Hensley’s Seed Co. September 3, 2026

Swiss Chard - Key Growing Information

A row of our signature Swiss chard variety, 'Bright Lights,' growing in the field.

SCIENTIFIC NAME:

Beta vulgaris

CULTURE:

Keep the soil pH above 6.0. Chard prefers cool to mild weather but has some heat tolerance. Seed germinates in soil anywhere from 40 to 100°F (4–38°C), best at 86°F (30°C). Seedlings take light frost and mature plants moderate frost, though some varieties may bolt if seedlings sit for long in temperatures in the low 50s°F (about 10–12°C) or below. In mild areas, chard may overwinter.

DAYS TO MATURITY:

Counted from direct sowing.

PELLETED SEED:

Pelleted seed needs steady soil moisture while it germinates. Store it cool and dry before planting and use it within a year of purchase. The pellets are size 18.0, which suits Stanhay seeders (belt size 18.0) and many of the precision seeders on the market. Note that these large pellets may be too heavy for air or vacuum planters. TRANSPLANTING: In early spring, start seed indoors or in a cold frame about 5–6 weeks before planting out, once hard frosts are becoming rare. Sow ½" deep, 2–3 seeds per cell in 72- or 128-cell flats, and thin to 1–2 plants per cell. Plant out 4–6" apart in rows 12–18" apart.

DIRECT SEEDING:

Bunching: from mid-spring into midsummer (or fall where winters are mild), sow ½" deep at about 6 seeds per foot in rows 12–18" apart, and thin to 4–6" for bigger leaves. Baby leaf: from mid-spring into late summer (or fall where winters are mild), sow ¼–½" deep at 2–4 seeds per inch in rows 2" or more apart. Sowing too thickly crowds and stunts plants, so the more seeds per inch you use, the wider the rows should be.AVG. DIRECT SEEDING RATE: Bunching at 6 seeds per foot in 24" rows: about 300' per oz., 3¼ oz. per 1,000', or 4½ lb. per acre. Baby leaf: about 4,000 seeds per 100', or 45' per oz.SEEDING RATE FOR PELLETED SEED: At 6–12 pellets per foot: 261,360–522,700 pellets per acre in 12" rows, or 174,240–348,480 in 18" rows. INSECT PESTS & DISEASE: Rotate crops to prevent Cercospora leaf spot and other problems.

HARVEST:

Bunching: cut or snap off mature leaves one at a time; new ones keep coming for repeat harvests. Baby leaf: cut with a knife once leaves reach the size you want, about 3–6", roughly an inch above the soil and above the basal plate so plants regrow cleanly. Cut again when leaves are back to size, in 5–14 days depending on variety. DECORTICATED SEEDS: Decorticated seed has been rubbed to remove the rough, corky edges that keep it from flowing evenly through mechanical seeders.

SIZED SEEDS:

"Sized" seed has been sorted to a uniform size, which makes spacing with mechanical seeders more accurate and germination more even. Swiss chard seed is sized unless the description says otherwise.

SEEDS/LB.:

From 23,700 to 48,500, averaging 30,900.

PACKET:

200 seeds per raw packet or 100 per pelleted packet; enough for about 33–34' of bunching chard or 5–6' of baby leaf.