Tips on growing celeriac

It ain’t no beauty queen but this root crop is delicious mashed, roasted and pureed. Celeriac is also known as root celery, turnip-rooted celery or knob celery – it originates from the same plant

SOW AND GROW

Get started: You can start celeriac from seed inside in late winter in warmer regions and transplant when established, or sow direct or plant seedlings from spring until early summer. In cooler parts of the country, sow in trays inside from early spring and sow direct or plant seedlings outside from midspring until early summer.

STEP-BY-STEP

If you are starting in seed trays or jiffy pots, just sprinkle seed directly into moist seed-raising mix and lightly cover. Or sow seed direct about 1cm deep. Germination takes 14-21 days. If growing in trays, pot on into individual pots when two or more true leaves have formed. Plant seedlings into the garden when 5-7cm tall and when all risk of frost has passed. Space plants 20cm apart with 40cm between rows.

GROWING TIPS

Celeriac likes cool, moist soil, so give it a spot with morning sun and afternoon shade or protection with shade cloth, especially if you are starting it later in the season.

This is a hungry crop and needs plenty of nutrition for the knobbly stem to swell up, so enrich the soil where you plan to grow it with compost, sheep pellets and aged manure before planting.

Avoid adding high-nitrogen fertiliser though as this can result in lots of leafy growth at the expense of the edible part. Remove side shoots as the plant grows so the plant can put its energy into fattening up the root.

Harvest the entire plant by digging them out of the soil when the bulbous stems are the size of a tennis ball. Trim the stringy roots off with a sharp knife.

Scrub the bulbous hypocotyl under running water.

STANDOUT VARIETIES

Celeriac Sedano di Verona has good bolt resistance with 1.8-2kg roots andMars has good disease resistance against leaf spot.

TROUBLESHOOTING

If celeriac gets hot and dry, it tends to elongate and bolt to seed

GET GROWING

This column is adapted from the weekly e-zine, get growing, from New Zealand Gardener magazine. For gardening advice delivered to your inbox every Friday, sign up for Get Growing at: getgrowing.co.nz rather than produce a characteristic round rootball, so water regularly in summer and mulch around plants.

It can be prone to aphids; blast them off with the hose regularly. It is also susceptible to septoria leaf spot; remove and dispose of affected leaves (put them in your rubbish not the compost).

The celery-like stems of celeriac are edible, but it’s the swollen base or hypocotyl for which it is prized.

Harvest celeriac before the bulbs get too big and woody.