Celery is a versatile vegetable that can be grown successfully in the UK, particularly in milder climates. It requires specific conditions to thrive, including cool temperatures, consistent moisture, and rich, well-draining soil. This guide will walk you through the steps to grow celery in the UK.
Choosing the Right Variety
There are several varieties of celery that can be grown in the UK, including:
- Self-blanching varieties (such as 'Golden Self Blanching') are easier to grow because they naturally blanch (turn pale) without the need for manual tying up.
- Traditional types like 'Utah' and 'Tango' are more suitable for gardeners who prefer a more traditional approach.
Soil Preparation
Celery prefers moist, well-draining, and fertile soil. It grows best in loamy or sandy loam soil, which should be rich in organic matter to hold moisture and provide nutrients.
- pH: Celery likes slightly acidic to neutral soil, ideally between 6.0 and 7.0. If your soil is too acidic, you can add garden lime to raise the pH.
- Soil texture: Ensure the soil is loose and well-draining, as celery does not thrive in compacted soil. If your soil is heavy, improve it by adding organic matter such as compost or well-rotted manure.
- Nutrients: Celery is a heavy feeder and needs nutrient-rich soil. Before planting, incorporate plenty of well-rotted compost into the soil to provide a steady supply of nutrients throughout the growing season.
Sowing Seeds
Celery is usually grown from seeds in the UK, which should be sown in early spring (around March or April) to give the plants enough time to mature.
- Indoors: Start seeds indoors in February or March in a warm, sunny spot or under grow lights. Sow seeds thinly on the surface of a seed tray, as they need light to germinate. Gently cover with a thin layer of compost or vermiculite.
- Germination: Keep the seeds at a temperature of 18-21°C (65-70°F) and maintain a moist environment. Germination typically takes 14 to 21 days.
- Thinning: Once seedlings have grown large enough to handle, thin them out to avoid overcrowding, leaving the strongest plants to grow.
Transplanting
Celery plants need to be hardened off before transplanting outside. This process involves gradually acclimatising the seedlings to outdoor conditions.
- Timing: Transplant celery seedlings outdoors after the last frost date in late spring (around May in most parts of the UK).
- Spacing: Space celery plants 30–45 cm (12–18 inches) apart in rows, with about 45 cm (18 inches) between each row to allow them plenty of room to grow.
- Planting: Celery needs a cool growing environment, so choose a location that gets partial shade or full sun with protection from hot winds. If planting in rows, ensure the soil is loose and well-watered.
Watering
Celery is highly sensitive to moisture levels, requiring consistent watering to keep the soil moist but not waterlogged. Irregular watering can result in poor growth or a bitter taste.
- Regular watering: Water the plants deeply and regularly, especially during dry spells.
- Mulching: Apply a layer of mulch around the base of the plants to retain moisture, keep the soil cool, and reduce competition from weeds.
Feeding
As a heavy feeder, celery will benefit from regular feeding throughout the growing season.
- Organic fertiliser: Apply a balanced organic fertiliser or a high-potash feed every 4–6 weeks during the growing season.
- Nutrients: Celery particularly benefits from a consistent supply of nitrogen, potassium, and calcium to support strong, healthy growth and prevent diseases like blight.
Blanching (Optional)
To achieve blanched celery (paler stems), you can either tie the stems up or cover them to exclude light. This is a traditional method to improve taste and texture.
- Blanching method: Start tying the celery plants once the stems are around 20–25 cm (8–10 inches) tall, and gradually cover them with cardboard or soil.
- Time: Allow the plants to blanch for 2–3 weeks before harvesting. If you don’t want to blanch your celery, you can skip this step.
Pest and Disease Control
Celery is susceptible to several pests and diseases, so it's important to keep an eye out for common issues.
- Common pests: Aphids, slugs, and snails are common pests that may attack celery. Use organic slug pellets or beer traps to control slugs, and wash off aphids with a jet of water.
- Diseases: Celery can suffer from fungal diseases like leaf spot or blight. To avoid these, ensure good air circulation around the plants, water at the base (to keep leaves dry), and practice crop rotation to reduce the build-up of soil-borne pathogens.
Harvesting
Celery can be harvested once the stalks have reached their full size, typically late summer to early autumn (around August to September in the UK).
- Cutting: Use a sharp knife to cut the celery stalks from the base of the plant. You can harvest individual stalks as needed or remove the entire plant at once.
- Storage: Celery is best used fresh, but you can store it in the fridge for up to two weeks. It can also be blanched and frozen for long-term storage.
Winter Care (Optional)
In colder areas of the UK, celery may struggle to survive winter temperatures.
- Overwintering: In areas with mild winters, celery can be overwintered by mulching heavily around the base of the plant. For colder regions, it’s best to treat celery as an annual and start fresh each year.
