At a glance
Ease of culture: Difficult
Where: All regions
Best climate: Cool conditions
When: Cool and temperate – late winter/early spring, late summer/early autumn; Subtropical – April to August; Tropical – April to July
Harvest: 14 weeks
• Celery likes moderate conditions – not too hot and not too cold. It hates frost and extreme heat.
• In cool and temperate regions, sow late winter to early spring, and again in late summer to early autumn.
• In frost-free sub-tropical zones, sow mid-autumn (April) to early spring (August).
• In the tropics, plant seed from April to July.
• Celery will thrive in full-sun or part shade
• Strong winds can damage and dry out plants, so choose a protected spot.
• Celery is a shallow-rooted plant with a high demand for water and nutrients.
• It grows best in a moist but well-drained soil that is organically rich.
• Add a minimum of a half-barrow load of compost or well-rotted manure per square metre and work it into the top 10-15 cm layer of soil. This will help improve drainage and retain moisture around the root zone.
• Spread a handful of balanced organic fertiliser evenly per square and work that in too.
• Mound the soil to further improve drainage and water it well, then leave it for a week before planting out seedlings.
• Raising your own celery plants from seed is slow and fiddly. If you’re new to gardening, buy seedlings from your nursery. This is also a good option for gardeners in warm areas where the growing season is short and you need to get plants in the ground quickly.
• Celery seed takes 2-3 weeks to germinate.
• The ideal temperature for germination is 15-21°C.
• Before sowing, soak the seeds in warm water for 24 hours. This will improve germination.
• The seeds are tiny, so don’t bury them. Sprinkle them over punnets of seed-raising and lightly press them into the surface.
• Water lightly and carefully, and keep the mix constantly moist until the seeds germinate.
• Once seedlings are big enough to handle, prick them out gently and plant them individually into small pots.
• Fertilise them once a week with a weak solution of seaweed and fish emulsion to kick them along.
• Seedlings take about 6 weeks to be big enough to plant out.
• When they’re ready to plant, space them 20-25cm apart in a block.
Watering and fertilising
• Keep celery well watered to avoid stress.
• Celery needs to be fed regularly. Fortnightly applications of liquid seaweed and fish emulsion will keep plants kicking along.
• Water and nutrient stress leads to dry, fibrous stalks.
• Mulch plants well to help hold moisture in the soil and reduce weed competition
Dark green celery can be quite bitter to taste. This is okay for cooking, but many people find it unpleasant to eat raw. Excluding light from the stems or "blanching" will produce paler stalks that are much sweeter. When plants are a decent size (close to harvesting), tie the stalks loosely then wrap the stems with thick newspaper, leaving the leaves sticking out at the top. The stalks will be pale and ready to harvest in around 2-3 weeks.
Celery bunches can be harvested whole (after 14 weeks) or, if you prefer, you can harvest individual stalks as you need them. This extends the harvest season.