Recently I have been on a soup making blitz and using loads of celery, but in my mind it is a summer salad vegie, clearly I am mistaken… Here in Melbourne you can plant celery as soon as the last frost has passed, and/or in late summer, to have ready for soups in late autumn!
I am a big promoter of growing from seed – but perhaps not for celery – seedlings are an easier option for this vegie. It can be planted in full sun to part shade and it is very important that the soil is rich and fertile. Celery is water hungry, but it also needs a well drained soil, so soil preparation is important. Dig in compost and manure, and mound up if drainage is an issue. Make sure soil is nicely damp BEFORE you plant. Plant the seedlings 25cm apart. Mulch around the newly planted seedlings with straw mulch.
The paler the celery, the sweeter it is. Excluding light is the trick. An easy way is using the square 1L milk cartons with the top and bottom cut off. When you estimate the celery is 2-3 weeks away from maturity, slip the milk carton over the top. Remember to ensure water goes both inside and outside the carton when watering. Because celery is such a gross feeder, give additional fertiliser every two weeks. You can use an all purpose liquid feed or blood and bone. The carton will keep the celery nice and compact, as well as pale and sweet. If you want crisp celery you need to water it very regularly. Make sure you give it a good, deep watering.
The outer stems can be harvested as the plant is growing, or you can wait and harvest the entire plant by slicing it off at ground level.