All about celeriac

AUTUMN is officially here, although it feels as though we have experienced it much earlier this year. In the Kitchen Garden, crops are coming to an end as they are harvested and start to go over with the shortening of daylight and the drop in temperature. One crop, however, that can withstand frosts down to -10°C is celeriac.

Celeriac is a biennial plant grown as an annual for its delicate celery-fennel tasting swollen stem. It is rich in potassium with moderate amounts of vitamin C and is super hardy. Celeriac was brought to the UK from Alexandria in the eighteenth century by writer and seedsman, Stephen Switzer.

The botanical name for celeriac is Apium graveolens var. rapaceum. The word Apium is derived from celtic apon meaning water; graveolens meaning strong smelling and rapaceum meaning turnip-like: the water loving, strong smelling, turnip-like plant. The celeriac plant belongs to the Apiaceae family, the same family as carrots, parsnips and parsley to name a few.

Celeriac needs a really long growing season.

For this reason it is best to start off seedlings in late winter or early spring in a propagator set to 18°C. If this isn’t an option then seedlings can be started in a cold glasshouse in late spring, although final stem sizes will be much smaller. Germination is often erratic so it’s advisable to sow several seeds per module, thinning out to the strongest. When seedlings are large enough to handle, transplant them individually to 7.5cm pots. At this stage, try to keep seedlings at temperatures between 13 - 16°C. Seedlings are at risk of frost and should be hardened off in late spring and planted outdoors when the risk of frost has passed. Plant out at least 30 cm apart in rows 45 cm apart with the crown just showing about the surface.

Celeriac can tolerate shade and damper parts of the garden, requiring rich fertile soil that holds onto moisture. Well-rotted manure should be incorporated into the soil in autumn and in summer the plants benefit from a mulch to conserve water. During dry periods, celeriac should be watered at least every other day. A weekly liquid manure feed can also be greatly beneficial in summer.

Celeriac plants are ready to harvest from September onwards right through to winter.

Plants should be lifted when they are between 7-13cm in diameter. With the onset of temperatures below -10°C, it’s important to protect plants with a layer of straw, fleece or bracken. If plants need to be stored, remove the roots and outer leaves, keeping the central tuft, and store in a cool shed in boxes of damp sand. They can also be lifted and transplanted to another part of the garden, heeling-in until required.

The biggest threat to celeriac are slugs. To help control slugs, limit their hiding places and keep the soil free from plant debris. Celeriac can also be affected by carrot fly and celery fly and the best way to control these are to grow plants under fine netting or polythene. Some good varieties include Monarch which has smooth skin and succulent flesh, Alablaster which is bolt resistant and high-yielding and Marble Ball which is strongly flavoured and stores well.

As well as having high nutritional value and a great taste, celeriac carries only 14 calories per 100g, making it excellent for anyone on a diet. To prepare the bulbs, scrub well then peel. Once cut, the flesh discolours quickly, so work quickly or place the bulbs in water containing lemon juice, lime juice or vinegar. Celeriac is fabulous grated on salads or made into soup. It can also be made into chips and makes an excellent accompaniment for either meat or fish. In France, cubed pieces are added to mayonnaise and Dijon mustard to make Celeri-rave remoulade. Bon Appétit!

Jobs to do

Support ripening fruit such as melons or squashes

Remove mildewed leaves

Cut out fruited canes on summer raspberries and hybrid berries

Harvest leeks as required

Plant onion sets and shallots

Plant garlic cloves

Harvest autumn cabbage

Cut back yellow asparagus ferns.

For more information on things to do in the garden this month visit rhs.org.uk

DIARY DATES

Until October 8, 10am – 4.30pm: The Natural Wood Exhibition

This exhibition celebrates the natural beauty of wood, with lovingly handcrafted wooden products such as furniture and homewares on offer, along with the chance to meet the makers and watch live demonstrations. Normal garden admission.

Sat, Oct 10 – Sun, Oct 11, 10am – 4pm: Autumn Food Festival

Celebrate the autumn harvest and experience all that’s fresh and tasty this season. The garden will be packed with local food stalls, expert advice, cookery demonstrations, tastings and displays. Take part in a ‘fungus foray’ around the garden to identify edible mushrooms, and appreciate an autumn apple display. There will also be a chance to enjoy traditional craft, artisan demonstrations and family activities inspired by the natural beauty of wood. Normal garden admission.