How to Grow Swiss Chard for an Endless Supply of Fresh Greens

How to Plant Swiss Chard

Swiss chard is a fast-growing vegetable that is ready to harvest in around 40 days.

Seeds can be directly sown into the garden about 1/2 inch deep and two inches apart in early spring or late summer. If you start seedlings indoors, plant them after the predicted last frost about four inches apart, taking care to minimize root disturbance.

The best planting site for Swiss chard receives full sun and has nutrient-rich, well-draining soil with plenty of organic matter.

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Swiss Chard Care

Light

Swiss chard needs full sun to partial shade with 6-8 hours of full sun producing the largest, healthiest plants. If you live in a hot climate, some shade from the strong afternoon sun is beneficial to prevent leaf wilt.

Soil

For the largest and healthiest plants, Swiss chard prefers soil with a high organic content, a neutral pH (6.0-8.0), and good drainage but still moist.

Water

Like most leafy greens, Swiss chard needs a consistent amount of water to stay healthy—about one to two inches of water per week depending on your climate and rainfall. Mulching around your plants and between the rows can help retain moisture.

Temperature and Humidity

The plants grow fastest in the cool temperatures of spring and fall, although they continue to produce leaves throughout the summer. Swiss chard is a sturdy plant that can tolerate some heat, humidity, and drought, but will not flourish without adequate moisture.

Fertilizer

If the garden soil is not nutrient-rich, apply a complete garden fertilizer such as 10-10-10 mixing it into the top three inches of soil before planting.

Pollination

Swiss chard produces tiny flowers that use wind and insects as pollinators. Pollination is not a concern since this is an annual crop.

How to Grow Swiss Chard From Seed

Swiss chard can be direct sown in the garden or started indoors and transplanted into the garden. You can sow directly in the garden when the soil temperature is at least 45°F.

1. Start plants indoors in a seed-starting mix about two to three weeks before your last expected frost date. The seeds will germinate in five to seven days.
2. Fill a seeding tray with seed staring mix. Sprinkle the seeds over the moistened mix and cover seeds with about 1/2 inch of soil.
3. Keep the tray moist and in bright, indirect light.
4. Transplant your seedlings from indoors after the danger of frost has passed.

How to Grow Swiss Chard in Pots

A Swiss chard plant will grow well in a container that holds at least two quarts of soil and is at least eight inches deep. Be sure the pot has good drainage holes and fill it with potting soil.

Add your Swiss chard seedling and water deeply. Place the container where it will receive at least six hours of direct sunlight daily. Water often to keep the soil moist.

Swiss Chard Varieties

• ‘Bright Lights’: A mixed variety, these stems are red, white, orange, pink, violet, and yellow mixed. It matures in 40 days.
• ‘Northern Lights’: Brightly colored stalks and midribs in shades of red, pink, yellow, and white. Matures in 42 days.
• ‘Ruby’: Ruby-red stems, reddish-green leaves, red veins that mature in 45 days.
• ‘Lucullus”: Just 40 days to maturity with dark green leaves and white stalks.

Harvesting Swiss Chard

The tastiest Swiss chard leaves are young and tender. You can start harvesting at any time for smaller leaves that can be eaten raw in salads. Or, wait until the leaves are around 12 inches long with a sturdier stem for cooking. Remove the largest outer leaves first with a sharp knife or garden shears. Continue harvesting single leaves to encourage new leaves to grow.

You can eat both the leaves and the stems. Mature leaves are chopped and cooked in sautés, soups, or stews. Stop harvesting when the plant bolts and goes to flower. The leaves will then be tough and bitter. If you can’t eat or share all of the leaves, just add them to your compost pile.

Pruning

Swiss chard does not require pruning other than removing mature outer leaves to encourage new growth. If a plant is overrun with insects, you may wish to cut it down to the soil line to help get rid of the pests. If the plant roots are healthy, Swiss chard will regrow after cutting.

Propagating

Swiss chard is commonly started from seeds or nursery seedlings, but it can be propagated from cuttings. Cuttings should be taken from the oldest leaves.

1. Use gardening shears to cut a mature stem from the bottom of the plant. Do not propagate from the plant’s center. Trim the bottom of the stem at a 45º angle leaving it 4 to 6 inches long. 
2. Dip the cut end in rooting hormone and insert it into a small container with drainage holes filled with moist soilless potting mix.
3. Keep the potting mix moist. Roots should develop in a few weeks. If you gently tug on the stem and feel resistance, the Swiss chard is ready to transplant.

Overwintering

Swiss chard is cold-tolerant and will continue to grow in the garden through frosts until temperatures drop to the mid-20s Fahrenheit. At that point, since the vegetable is an annual it is best to allow the plants to die and plant again in the spring.

Common Pests & Plant Diseases

Swiss chard leaves can be affected by Cercospora leaf spot, causing older infected leaves to yellow and die. This fungal disease usually occurs when conditions are warm and humid. To help prevent the spread, you can use a fungicide or remove infected leaves and pull up and discard badly infected plants. Use dense organic mulch around plants and water only at the base of plants, not overhead.

Leafminers will feed on the surface of Swiss chard leaves. They are considered minor pests, but heavy infestations can reduce leaf quality and yield. Remove infested leaves and plants to destroy them as a primary control.

Root-knot nematodes are small colorless roundworms that infect plant roots. While there is no chemical treatment, if a plant is wilting, pull it up and inspect the roots. If they look “knotty” discard the plant. Rotate Swiss chard to another area of the garden next year and incorporate compost to help suppress root-knot nematode populations.