Celery & Celeriac

How to Grow Celery & Celeriac

The essential guide to growing Celery & Celeriac (Apium graveolens var. dulce) from seed; with notes on germination, cultivation, harvest and even kitchen uses. We all know celery but celeriac is less well known in Australia but used as a good storage root in Europe.

Seeds per gram: about 2 500
Optimal germination: 21 – 25 °C   =>   14 – 21 days to sprout

Feed requirements:

• Heavy feeder; work compost and a balanced organic fertiliser into the bed, then side-dress every three to four weeks.
• Keep soil uniformly moist and mulch thickly.

Sowing and Transplanting:

• Start seed indoors 10–12 weeks before the last spring frost.
• Sow 3 mm deep in seed-raising mix.
• Transplant when nights stay above 13 °C to prevent bolting; set plants 25–30 cm apart with 60–75 cm between rows.

Growing On:

• Water deeply two or three times a week; celery hates drying out.
• Blanch stems for tenderness by hilling soil or wrapping cardboard collars 2–3 weeks before harvest.
• Cutting-celery (Par-cel) offers the same flavour with less fuss if space or heat is an issue.
• Watch for boron deficiency in sandy soils and correct with a single dilute borax drench when seedlings are 5–10 cm tall.

• Celeriac - extra notes:
  • Celeriac quite likes a bit of shade (3-4 hours) as it can help with root quality in hot weather.

  • Remove the lowest leaves as the crown enlarges so the root swells evenly.

  • Avoid late-season nitrogen surges—they soften roots.

Problems to Watch:

• Slugs and snails relish young seedlings—use traps, barriers or night patrols.
• Carrot fly can be excluded with insect-net row covers.
• Prolonged cool nights (< 13 °C for ten days) trigger bolting.
• Downy mildew and leaf spots thrive in humid, crowded beds—maintain airflow and avoid overhead watering.

• Celeriac - extra notes:
  • Boron deficiency causes brown centres.
  • “No-bulb” syndrome results from heat stress, irregular watering or harvesting too early.

Harvest and Storage:

• Twist or pull outer stalks as needed, or cut the whole head at soil level.
• Refrigerate in a perforated bag for up to two weeks; dice and freeze for soup bases or dehydrate leaves for winter seasoning.
• Celeriac - extra notes:
  • Loosen soil with a fork, lift the bulb and trim foliage to 1–2 cm.
  • Store two to three months in a cool, humid cellar (0 – 4 °C) or cube, blanch and freeze.
  • Delicious mashed with potato or shaved raw in salads.

  • Nutrition nugget: Celeriac is fibre-rich, lower-carb than potato and a notable source of vitamin B6.

Fun fact: Celery is 94 % water yet delivers antioxidants and roughly 37 % of your daily vitamin K in just one cup.