Good question – though growing celery has been made a lot easier with the arrival of self-blanching varieties, it’s still a tricky enough prospect to grow well. But stick with it and it will reward you well. Celery is incredibly good for you and is a staple “stock-pot” veg. It tastes great raw and freezes well. Traditionally, growing celery was incredibly labour intensive because trenches had to be prepared to grow them in and then the celery had to be regularly earthed up to blanch or whiten the stems. Most GIYers now grow self-blanching (green) celery which does not require earthing up or trenching. Happy days.
Dig the bed in the winter and add plenty of well rotted manure or compost. Add organic fertiliser (e.g chicken manure pellets) before planting. Slow to germinate so grow in module trays and then transplant. Sow in March for planting out in May (when they have four to six true leaves). Harden off before planting out. Self-blanching celery is typically planted in blocks rather than in rows, so the plants shade each other from light (thereby improving the blanching process).
Blanching celery makes the stems go white and more tender. Even “self-blanching” varieties benefit from blanching – homemade collars can be made from strips of black plastic wrapped around the plant. Traditional trench celery is blanched by “earthing up” the trench in which it was sown. Water celery well in dry weather – it’s a thirsty plant and if the soil dries out the stems won’t swell. If leaves go yellow, apply an organic feed (e.g. nettle or comfrey tea).
Celery will be ready in approx 40 weeks – usually August-Oct. Lift as required but finish harvesting when frosts arrive. Use a fork to gently lift the plant, roots and all. A head of celery will keep in the fridge for up to 3 days.
Slugs like it. Also prone to celery leaf miner (tiny maggots that cause leaf blisters) and leaf spot (brown spots on leaf that look like blight).