At a glance
- Celeriac and stalk celery are the same species, bred toward two goals: a fat root or juicy stalks.
- Both are light germinators and are started indoors on the windowsill from mid February. Growing your own pays off, seedlings are often scarce.
- Plant out only after the last frosts, mid May · CW 19 to 22. Cold at the seedling stage makes celery bolt later.
- Celeriac is planted shallow, never deep. Otherwise it throws side roots instead of a round bulb.
- Keeping it evenly moist is half the battle. Drought stress and leaf spot disease are the most common worries.
Celery is a vegetable for patient people. From sowing in February to harvest in October, a good eight months pass, and for much of that time nothing seems to happen. Then, in late summer, the plant takes off and the bulb swells week by week. Anyone who has once lifted a home grown celeriac out of the soil, caught that savoury scent, understands why the long wait is worth it. This bed holds the aroma for the entire soup season.
Two Plants, One Name
When a garden catalogue simply says "celery", it actually means two different crops that are botanically the same species: Apium graveolens. Celeriac (var. rapaceum) forms the thick, round root you know from vegetable soup. Stalk celery (var. dulce), also called stem or blanching celery, grows upward instead and delivers thick, juicy leaf stalks for eating raw or braising.
Cultivation is almost identical for both: same sowing time, same demands on soil and water, same sensitivity to cold. The big difference comes at the end, at harvest and in care. With celeriac it is all about the root, with stalk celery about the stems. Grow both and a single sowing covers half your kitchen.
Apium graveolens var. rapaceum
- Familie
- Umbellifers
- Standort
- Full sun
- Saison
- Sowing Feb to Mar · Harvest Oct to Nov
- Wasserbedarf
- High, evenly moist
- Frosthärte
- Frost sensitive, to about -3 °C
Starting in February: the Light Germinator on the Windowsill
Celery needs a long lead time, so its season begins earlier than most vegetables: from mid February to early March. That timing matters, because celery is a light germinator. The tiny seeds are only pressed onto the moist seed compost, not covered with soil, at most dusted thinly with sand. At around 20 °C they germinate slowly, often only after two to three weeks. Do not lose patience, that is part of it.
As soon as the seedlings show their first true pair of leaves, prick them out into individual pots. Then comes the most common raising mistake: keeping celery too cool. If it is grown for a long stretch below about 12 to 15 °C, that acts like a winter. The plant thinks a year has passed and later bolts to flower in the bed instead of forming a bulb or thick stalks. So keep the young plants bright and moderately warm, neither coddled nor chilled.
Reliable celeriac varieties for the home garden are 'Prinz' and 'Monarch', both with white flesh that stays tender. For stalk celery, 'Tango' dependably gives tender stems with barely any strings. If starting seed on the windowsill feels too early or too fiddly, you can also buy ready seedlings in May. They tend to sell out fast, though, precisely because so many gardeners shy away from raising their own.
Planting Out in Mid May: Never Too Deep
Celery is frost sensitive and may only go outdoors after the last frosts, so mid May · CW 19 to 22. The soil should be deep, humus rich and well supplied with mature compost, because celery is a heavy feeder with high water needs. A sunny spot is a must.
Prepare the bed
One to two weeks before planting, work mature compost and a handful of horn shavings shallowly into the soil. On heavy soils loosen thoroughly, on sandy ones extra compost helps against quick drying out.
Harden off the seedlings
A week before planting, set the pots outside during the day in a sheltered spot. That way the plants get used to sun and wind and settle in faster after the move.
Plant shallow
Set celeriac so that the crown stays just above the soil. If the future bulb is covered with earth, it throws many side roots and stays small and knobbly. Spacing is about 40 to 50 cm in every direction.
Water in
Water the freshly set plants generously and keep the soil constantly moist for the first few weeks. This is when it is decided whether the roots take hold well.
If cold nights below about 10 °C still threaten after planting, cover the seedlings with fleece. A late cold spell can trigger bolting even though the raising went flawlessly until then. That is no drama, just a precaution for the cool second half of May.
The Whole Summer Is About Water
Celery originally comes from salty coastal meadows and marshy edges. You notice that origin in the bed: it wants to stay evenly moist all summer long. Drought stress is the most common reason for small, bitter bulbs and for stalks turning hollow. Water consistently in July and August and the most important work is already done.
- Water evenly
Better to water less often but deeply than a little every day. The soil should never dry out completely. A mulch layer of grass clippings or straw holds the moisture and saves watering.
- Feed again in July
As a heavy feeder, celery welcomes a second helping. Diluted nettle or comfrey liquid feed every two to three weeks covers its hunger. From late August give no more nitrogen so the bulb ripens.
- Expose the bulb
From September, push the soil and the outer, lying leaves away from the celeriac bulb. That lets in light, makes it rounder and the skin smoother. The inner heart leaves stay in place.
- Blanch the stalks
For especially mild, pale stalks, tie stalk celery loosely together in September and earth it up or wrap it in paper. Modern varieties, however, also taste tender unblanched.
Celery is a grateful neighbour. It gets along well with leek, bush beans, cucumber and spinach, and celeriac counts as a classic partner next to cabbage because its scent confuses the cabbage white butterfly. Avoid the direct neighbourhood of potatoes, carrots and parsley, though. And keep the rotation: after umbellifers such as carrot or parsnip, leave four years before returning, otherwise soil fungi build up.
Celery must never go thirsty in summer, and never freeze in autumn.
Old gardener's rule
When Spots Appear on the Leaves
The most common real worry with celery is leaf spot disease (Septoria). It shows as small, round, brown spots with a pale centre, often as early as high summer, and spreads quickly in warm, humid weather. It weakens the plant and slows bulb growth.
Remove affected leaves at once and put them in the household waste, not on the compost, or the fungus survives. Always water at the root, never over the foliage, and keep generous spacing for good air flow. The pathogen often already sits in the seed, so with recurring outbreaks certified, treated seed is worth it.
Two smaller worries come on top. The celery fly lays its eggs in the foliage, and its larvae mine tunnels into the leaves. An insect net from the start keeps them reliably away. And heart rot, a brown, rotten core in the bulb, is usually a sign of boron deficiency: it appears on light, dry soils and can be avoided through even moisture and a handful of seaweed lime in spring.
Harvest and Storage from October
Celery has time. You harvest it late, usually in October or November, just before the first stronger frost arrives. Light night frosts down to about -3 °C the bulbs shrug off in the ground, but lasting frost turns them mushy. Lift the bulbs carefully with a digging fork so they do not tear.
Harvest in good time
Get the bulbs out of the bed before the first hard frost. With bare frost forecast, rather a day too early than too late.
Cut the leaves, keep the roots
Cut the foliage off just above the bulb. Leave the fine roots on for storage, that keeps the bulb fresh longer.
Store cool and moist
Bed the bulbs with clinging soil into moist sand and place them in a dark, frost free cellar just above 0 °C. That way they keep all winter.
Stalk celery is harvested continuously as soon as the stalks are sturdy enough, usually from August. You either break out single outer stalks or cut the whole plant off just above the ground. Unlike celeriac, it barely stores, it wants to be used fresh. A few weeks in the vegetable drawer, wrapped in a damp cloth, is the most you get.
Common questions about celery
Why does my celeriac form no bulb, only lots of roots?
Usually it was planted too deep. The crown must sit just above the soil. If the future bulb is covered with earth, it throws side roots everywhere instead of a smooth ball. Next time set it shallower and in September push the soil away from the bulb.
Why does my celery bolt instead of forming a bulb?
Almost always because of cold in its youth. If the young plants stood for a long time below about 12 to 15 °C, the plant treats it as a winter survived and flowers in the first year. Raise the seedlings warm and plant out only after the last frosts, protected with fleece on cold nights.
Can I sow celery directly into the bed?
In the German speaking region this is not advisable. The growing period is too long and germination too slow and warmth hungry. By the time direct sowings are big enough, the season is not sufficient for a decent bulb. Starting indoors from mid February on the windowsill is the safe route.
What helps against brown spots on celery leaves?
That is usually leaf spot disease. Remove affected leaves and dispose of them in the household waste, water only at the root and provide airy spacing. With recurring outbreaks the following year, use certified, treated seed and keep the crop rotation.
Does celery tolerate light frost in autumn?
Short, light night frosts down to about -3 °C the bulb survives in the ground, especially under a cover of leaves or fleece. Lasting or stronger frost makes it rot. So harvest before the first forecast bare frost and store the bulbs cool in moist sand.
Spotted a mistake?
