Root vegetables
Celeriac
Apium graveolens var. rapaceum
Timings for your region
Suggested: Moderate · Explained in the glossary
Start indoorsmid February – late March
Plantingearly May – early June
Harvestmid September – late October
Practical tip
A light germinator — press it on, do not cover it. Plant shallow: the bulb should sit on the soil, not in it.
Origin & history
The wild form of celery grows on salty coasts and salt meadows in Europe; in ancient Greece the foliage was woven into victors’ wreaths long before anyone ate the root. The bulbous form only appeared in the 16th and 17th centuries and was grown mainly in northern and central Europe — which is why English once called it “German celery”. Celeriac, stem celery and leaf celery are botanically the same species, just different varieties.
Varieties
Look for bolt-resistant varieties with smooth skin and few side roots — the more wrinkled and whiskery the bulb, the more of it ends up in the compost when you clean it. Varieties such as “Prinz” stay white when cooked, while older types go greyish. Because the pre-culture takes ten weeks and the seed is tiny, many people prefer to buy young plants; if you do, pick sturdy ones with a short, firm heart.
Care
Celeriac is a hungry crop with a high water demand — let the bed dry out in between and the bulb stays small and turns woody; mulch keeps the moisture in. A second dressing of compost in July pays off. From late August take off the outer, flat-lying leaves and cut away the roots on top of the bulb so it grows round and smooth — leave the heart alone, or you slow the swelling down.
What can go wrong
The classic mistake is planting out too early: a cool week below 10 °C after planting makes celeriac bolt in summer instead of forming a bulb. Brown leaf spots (Septoria) usually arrive with the seed and spread on wet foliage — space the plants widely, water at the base, take off affected leaves and keep a three to four year break. Bulbs that are hollow or brown inside point to heavily limed, too dry soil.
Harvest, storage & kitchen
Lift before hard frost — the bulb takes a light frost, a hard one makes it glassy. Twist off the foliage, trim the beard of roots and pack the bulbs in damp sand in a cool cellar, where they keep into spring. Be generous when peeling, the skin stays tough; cut surfaces go grey in the air, so mix grated celeriac with lemon straight away. Chopped fine, the leaves are the green in a soup.
All timings are guide values for the given climate, not a guarantee. Weather, aspect and variety all have a say.