Celery growing guide

Introduction

Celery is a popular vegetable known for its crisp stalks and aromatic flavour, often used in soups, salads, and as a snack. Growing celery in the southeast UK can be rewarding, though it requires some attention to detail to achieve those crunchy, succulent stalks.

Why grow celery?

Celery is rich in vitamins A, C, and K, as well as potassium and fibre. Homegrown celery often has better flavour and texture than store-bought varieties, and growing your own ensures it’s free from pesticides and chemicals. Additionally, celery’s continuous harvest can provide fresh produce for several months.

Suitability for different growing environments

Celery prefers a cool, moist environment and thrives in well-drained soil with plenty of organic matter. It can be grown in the ground, raised beds, or large containers. Consistent watering is crucial to prevent the stalks from becoming tough and stringy.

Lifecycle

Celery is a biennial plant typically grown as an annual. It is usually started indoors in early spring and transplanted outside after the last frost. Celery requires a long growing season, taking around 100-130 days from sowing to harvest.

Sowing and harvesting periods

  • Sowing: Indoors from February to April
  • Transplanting: After the last frost, typically May
  • Harvesting: July to October

Recommended varieties

Popular celery varieties for the UK include:

  • ‘Lathom Self-Blanching’
  • ‘Victoria’
  • ‘Green Sleeves’
  • ‘Giant Pascal’

How to sow

Start celery seeds indoors 10-12 weeks before the last expected frost date. Sow seeds thinly on the surface of moist compost and lightly cover with a thin layer of vermiculite. Keep the trays in a warm place, around 70°F (21°C), and ensure the compost remains moist.

How to prick out/pot on

When seedlings are large enough to handle, transplant them into individual pots or module trays to grow on until they are ready to be planted outside. Harden off the seedlings by gradually acclimatising them to outdoor conditions over 7-10 days before transplanting.

Where to plant

Choose a sunny or partially shaded spot with rich, well-drained soil. Prepare the soil by incorporating plenty of organic matter, such as well-rotted manure or compost, to improve moisture retention and fertility.

How many to plant (spacing)

Space celery plants 8-10 inches (20-25 cm) apart in rows 12 inches (30 cm) apart. This spacing allows for adequate air circulation and room for the plants to grow.

How to plant

Plant celery seedlings deeply, ensuring the base of the leaves is just above the soil surface. Water well after planting to help the plants establish. Mulch around the plants to retain moisture and suppress weeds.

Protecting your plants

Celery can be susceptible to slugs, snails, and aphids. Use organic methods like slug pellets, beer traps, or barriers to protect young plants. Covering plants with horticultural fleece can also help prevent pest damage and provide some frost protection in cooler weather.

How to feed and water

Celery requires regular watering to keep the soil consistently moist. Water deeply and regularly, especially during dry spells. Feed plants every two weeks with a liquid fertiliser high in potassium to encourage strong growth and healthy stalks.

How to propagate, prune/manage while growing

Celery is typically grown from seed. Pruning is not necessary, but you should remove any damaged or yellowing leaves to maintain plant health. Blanching, or excluding light from the stalks to make them tender, can be done by wrapping the stalks in newspaper or using plastic collars.

How and when to harvest

Harvest celery stalks when they are about 12-18 inches (30-45 cm) tall and before they become tough. Cut individual stalks from the outside of the plant as needed, or harvest the whole plant by cutting at the base. Regular harvesting encourages the plant to produce new stalks.

How to store

Celery is best used fresh but can be stored in the refrigerator for up to two weeks. To extend its shelf life, wrap the stalks in aluminium foil before refrigerating. Celery can also be blanched and frozen for later use.

How to eat/cook

Celery can be eaten raw in salads, with dips, or as a crunchy snack. It is also commonly used in soups, stews, and casseroles for added flavour and texture. Cooked celery is a delicious addition to stir-fries and roasts.

How to deal with pests and disease

Common pests include slugs, snails, and aphids. Handpick pests, use organic slug pellets, and encourage natural predators like ladybirds. Ensure good air circulation and avoid overhead watering to prevent fungal diseases such as celery leaf spot and blight.

When and how to remove the plants

Remove plants at the end of the growing season or when they start to decline. Cut the plants at ground level and compost any healthy plant material. Prepare the bed for the next crop by adding compost or well-rotted manure.

What to plant before and after

Celery can follow nitrogen-fixing crops like peas or beans, which enrich the soil. It also does well after leafy greens or root vegetables like carrots and beetroot. After celery, plant legumes like peas or beans to help restore nitrogen levels in the soil. Alternatively, grow brassicas like cabbage or kale, which benefit from the rich soil left by the celery.

What to interplant with

Good companion plants for celery include onions, leeks, and tomatoes. These plants help deter pests and can improve the growth and flavour of celery. Avoid planting celery near carrots or parsley, as they compete for similar nutrients and can attract the same pests.

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