How to Grow Celery

Celery and tomatoes are mutually beneficial neighbours: celery's pungent foliage — rich in phthalides and terpenes — repels aphids and whitefly that commonly attack tomatoes, while tomato's dense canopy provides partial shade that reduces celery bolting in warm spells.

Broad beans harbour Rhizobium bacteria in root nodules that fix atmospheric nitrogen into plant-available ammonium, directly enriching the soil around the nitrogen-hungry celery. Chop and drop bean stems at the end of the season to release stored nitrogen as they decompose.

Runner beans fix atmospheric nitrogen via Rhizobium root nodules, steadily releasing ammonium into the soil that feeds nitrogen-hungry celery over the season. Grow them on a trellis directly behind the celery row so the beans don't shade out the shorter crop.

Celery's aromatic phthalide compounds act as an olfactory mask, disrupting the host-location ability of cabbage white butterflies and reducing egg-laying on nearby brassicas. Interplant celery every third or fourth cabbage to create a distributed chemical barrier.

Celery and leeks share similar moisture requirements and grow to compatible heights, making efficient use of bed space without competing aggressively. Their combined volatile profiles — phthalides from celery and sulphur compounds from leeks — create a mixed scent that confuses a wider range of pests than either alone.

Onion's sulphur volatiles and celery's phthalide scent together create a layered aromatic barrier that confuses a broad range of leaf-feeding insects navigating by smell. Both crops also prefer consistent moisture and similar pH, so they thrive under the same watering regime.

Both celery and parsnip belong to the Apiaceae family and share the same fungal and bacterial pathogens — most notably celery leaf spot (Septoria apiicola) and Sclerotinia — which can spread readily between them. Maintain at least 60 cm separation and avoid planting one in soil where the other grew the previous season.

Celery and potatoes both draw heavily on potassium and phosphorus, creating direct root-zone competition that stunts both crops when grown in close proximity. Potatoes also produce allelopathic glycoalkaloids that leach into the surrounding soil and can suppress celery seedling establishment; keep them at least 50 cm apart.