Celery seedlings don’t like having their roots disturbed so handle them with care and try to keep a small amount of mix intact around the roots.
For green celery, simple pick outside stems with a sideways pull to break them off at ground level.
Celery plants can be ‘blanched’ three to four weeks before harvesting by wrapping black polythene or thick newspaper around the stems from ground level to about 40cm high. The stalks will pale and be ready in 2-3 weeks.
Keep plants well watered and fed to avoid stress, otherwise you will end up with dry, fibrous stalks.
To maximise growing space in a pot, try sowing baby lettuce or microgreens around the celery. Take care not to overcrowd as the plants will compete for nutrients.