Swiss chard (Beta vulgaris subsp. vulgaris) is a versatile and hardy leafy vegetable that can be grown year-round in the UK. It’s prized for its brightly coloured stems and nutritious leaves, which are packed with vitamins and minerals. Swiss chard thrives in cool weather, making it an ideal vegetable for the UK climate. Here’s a guide to help you grow Swiss chard successfully in your garden.
Choosing the Right Variety
There are several varieties of Swiss chard to choose from, each offering different colours and flavours. Some popular varieties include:
- ‘Rainbow’: This variety is known for its vibrant stems in shades of red, orange, yellow, and white, while the leaves are dark green. It’s often grown for its ornamental appeal as well as its culinary use.
- ‘Fordhook Giant’: A larger, classic variety with broad, deep green leaves and thick white stems.
- ‘Bright Lights’: Known for its colourful stems in red, yellow, and white. It’s both attractive and edible.
- ‘Lucullus’: A variety with thick, pale green stems and large, tender leaves. It’s good for both baby leaves and mature harvests.
Choose a variety based on your aesthetic preferences and the size of your garden or plot, as some varieties can grow quite large.
Soil Requirements
Swiss chard is adaptable and can grow in various soil types, but it prefers fertile, well-drained soil to thrive.
- Soil pH: Swiss chard grows best in soil with a slightly acidic to neutral pH, ideally between 6.0 and 7.5. If your soil is too acidic, you can raise the pH by adding garden lime.
- Soil texture: It prefers loamy soil that is rich in organic matter. Well-draining soil is important to prevent waterlogging, as Swiss chard does not tolerate soggy roots.
- Soil fertility: Swiss chard is a heavy feeder, so the soil should be enriched with compost or well-rotted manure before planting to improve its nutrient content.
Planting Swiss Chard
Swiss chard can be directly sown in the ground or started indoors, though in the UK, it’s often best to start directly outside once the weather warms.
- Sowing seeds outdoors: In the UK, sow Swiss chard seeds outdoors from March to May for a spring or early summer crop. Sow the seeds about 2 cm deep, spaced 30 cm apart in rows. Thin the seedlings to around 30 cm once they are large enough to handle.
- Sowing in pots: If you prefer to start indoors or in a greenhouse, sow seeds in late winter or early spring (around February to March). Plant seeds in small pots or trays, and when the seedlings are large enough, harden them off and transplant them into the garden in April or May.
- Spacing: Swiss chard requires enough space for its broad leaves to grow, so space rows about 30-40 cm apart. If growing in rows, space plants 30 cm apart within the row.
Location and Spacing
Swiss chard prefers a sunny to partly shaded spot, making it a great choice for most UK gardens.
- Sunlight: Ideally, Swiss chard needs at least 4-6 hours of sunlight per day. It can tolerate some shade, which can help prevent bolting (flowering and going to seed) in hot weather.
- Spacing: Space plants 30 cm apart to allow room for their large leaves. If growing in rows, leave at least 30-40 cm between rows to make it easier to harvest and maintain good air circulation around the plants.
Watering and Mulching
Swiss chard grows best with consistent moisture, especially during dry spells.
- Watering: Keep the soil evenly moist, but not soggy. Water regularly, particularly during dry periods, and always water at the base of the plant to avoid wetting the leaves, which can encourage disease. A deep watering once a week is usually sufficient, especially in cooler weather.
- Mulching: Apply a layer of mulch around the base of the plants to help retain moisture, suppress weeds, and regulate soil temperature. Organic mulches like compost or straw are ideal for Swiss chard.
Feeding and Fertilising
Swiss chard is a nutrient-hungry plant, so regular feeding is essential for healthy growth and a good yield.
- Compost and organic matter: Incorporate well-rotted compost or manure into the soil before planting. This provides a slow-release source of nutrients throughout the growing season.
- Fertilising: After planting, feed Swiss chard with a balanced fertiliser every 4-6 weeks during the growing season. Use a fertiliser that is rich in potassium and phosphorus to encourage healthy leaf growth and strong stems.
- Avoid too much nitrogen: While Swiss chard is a heavy feeder, too much nitrogen can encourage excessive leaf growth at the expense of flavour. Opt for a balanced or low-nitrogen fertiliser.
Pruning and Maintenance
Swiss chard is a low-maintenance crop, but a few simple care tasks can help it thrive.
- Harvesting leaves: You can start harvesting young Swiss chard leaves when they are around 10-15 cm tall. Harvest outer leaves first, allowing the inner leaves to continue growing. This will encourage the plant to produce more leaves. Regular harvesting also prevents the plant from bolting (flowering and going to seed).
- Removing flower stems: If your Swiss chard begins to flower, it’s best to remove the flower stems immediately to prevent the plant from going to seed. Flowering is a sign that the plant is stressed or that the growing season is drawing to an end.
Pest and Disease Control
Swiss chard is relatively pest-resistant, but it can still be affected by some common garden pests and diseases.
- Pests: Aphids, slugs, and snails can damage Swiss chard. Aphids can be controlled with insecticidal soap or a strong jet of water, while slugs and snails can be kept at bay with organic slug pellets or traps.
- Diseases: Swiss chard can be affected by downy mildew, powdery mildew, and leaf spot diseases. To reduce the risk of disease, ensure good air circulation around the plants and avoid overhead watering. If disease does strike, remove infected leaves immediately and dispose of them.
Harvesting Swiss Chard
Swiss chard is a cut-and-come-again vegetable, meaning you can harvest leaves continuously throughout the growing season.
- When to harvest: Start harvesting outer leaves when they reach about 10-15 cm tall, and leave the centre of the plant to continue growing. This will encourage new leaves to form.
- Mature plants: Once the plant is fully mature, you can harvest larger, more mature leaves. The leaves will be more fibrous at this stage but still edible, especially when cooked.
- Bolting: If the plant begins to bolt (flower), the leaves may become tough and bitter. It’s best to remove the flower stalk to stop the plant from flowering and producing seeds.
Overwintering Swiss Chard
Swiss chard is hardy and can be overwintered in the UK, especially if you live in a milder region.
- Winter care: In colder climates, cover the plants with horticultural fleece or a cloche to protect them from frost. You can also mulch heavily around the base to insulate the roots and keep the plants growing through winter.
- Hardiness: Swiss chard can survive through the winter in milder UK regions, and in spring, it will produce new growth for an early harvest.