OnionAllium cepa

Onion

Onions

1. Allium ascalonicum
2. Cepa vulgaris
3. Allium esculentum

1. bulb onion
2. common onion
3. onion plant

1. bulb onion
2. common onion

1. Bolle
2. Zipolle

1. brown onion
2. yellow onion

1. onon

1. NameZwiebel

   Languagede

   Shared with

   1. Blumenzwiebel

   Clarification

   Refers specifically to the crop species Allium cepa, not to the general botanical storage organ.

1. onion
2. bulb onion
3. common onion
4. Allium cepa

1. Tracheophyta
2. Liliopsida

Amaryllis family

1. Allium fistulosum
2. Allium porrum
3. Allium sativum
4. Allium schoenoprasum

1. bulb
2. shoot
3. leaves

Usually treated as an annual crop in home gardens and commercial cultivation via sets or seeds, but botanically biennial for seed production.

The bulb onion (Allium cepa) is one of humanity's oldest cultivated plants and an essential staple in any self-sufficient garden.

Already valued in ancient Egypt as a burial offering and medicinal plant, the onion was spread across Central Europe by Roman legionaries.

1. Taskplanting_sets

   Label

   Planting onion sets

   Priorityhigh

   Months

   1. 3
   2. 4

   Conditionfrost_free_soil

   Estimated effortmedium

   Notes

   Plant onion sets so that the tips are just showing above the soil surface.

1. Taskmain_harvest

   Label

   Onion harvest

   Priorityhigh

   Months

   1. 8
   2. 9

   Conditiondry_weather

   Estimated effortmedium

   Notes

   Harvest onions during dry weather and let them cure for a few days.

Full sun

Open, airy (helps prevent onion fly)

Medium loam, humic sandy loam

Excellent, not prone to capping or waterlogging

Moderate; thoroughly during dry spells in June

Well-rotted compost incorporated the previous autumn

Optional light organic top-dressing in May

Excellent companion plant for carrots to mutually deter pests (carrot and onion flies).

1. solanaceae
2. cucurbitaceae

1. fabaceae
2. asteraceae

Due to the risk of nematode transmission and fungal soil pathogens, a rotation break of at least 4 years should be maintained between Allium species.

1. Slugnitrogen_deficiency

   Name

   Nitrogen deficiency

   Symptoms

   Stunted growth, pale green to yellowish discoloration of the leaves starting from the tips.

1. Slugbolting

   Name

   Bolting (Premature flowering)

   Cause

   Cold shock during early growth stages (especially in large or prematurely planted sets).

1. Flies (Onion fly, leaf miners)
2. Thrips
3. Nematodes

1. Downy mildew
2. Neck rot (Botrytis)
3. Root rot

1. Use of fine-mesh insect netting immediately after planting.
2. Choose breezy, open locations to ensure quick drying of foliage.
3. Strict adherence to crop rotation intervals.

In case of wilting without visible foliar pests, always inspect the base of the bulb for maggot damage or fungal mycelium.

1. Slugperonospora_destructor

   Severityhigh

   Conditions

   1. Prolonged leaf wetness
   2. Moderate early summer temperatures

   Affected parts

   1. Leaves
   2. Foliage

   Prevention

   1. Wide spacing for excellent air circulation
   2. Avoid overhead irrigation

   Organic control

   1. Strengthen plants with horsetail extract
   2. Remove infected leaves promptly

1. Symptom

   Foliage yellows prematurely, collapses limply, and bulb rots

   Possible causes

   1. delia_antiqua
   2. waterlogging

   First checks

   1. Dig up the bulb base and check for small white maggots.
   2. Check soil moisture levels and drainage efficiency.

1. Germination and emergence (onion shoots appear)
2. Vegetative growth (development of leaves)
3. Bulb initiation (swelling begins)
4. Main bulb expansion
5. Maturation (foliage falls over and dries out)
6. Dormancy (rest period of the cured bulb)
7. Sprouting and inflorescence development (in the second year)
8. Flowering (umbel flowering)
9. Seed maturation

In its first year, the plant undergoes purely vegetative stages until the storage bulb matures. The generative phase with flowering and seed production only occurs after a cold period in the second year.

Spherical umbel-like cluster with numerous whitish to greenish individual flowers on a hollow scape.

1. Manual harvest by carefully pulling or digging up with a spading fork.

Single main harvest per plant; individual plants can be harvested early as green onions or bunching onions if needed.

1. The foliage naturally falls over (lodging).
2. More than two-thirds of the foliage has yellowed or dried out.
3. The outer bulb skins have developed their variety-specific coloration.

After pulling, let the bulbs cure for a few days on the bed in dry weather or in a well-ventilated, rain-protected location until the necks are completely dry.

Storage vegetable

3 to 6 months (up to 8 months depending on the variety and under optimal conditions).

1. Fresh storage (whole bulbs)
2. Freezing (chopped)
3. Pickling (e.g., pearl onions)
4. Dehydrating (onion powder / fried onions)

1. Excellent for raw consumption, sautéing, frying, boiling, and braising.
2. Serves globally as a fundamental seasoning ingredient for savory dishes, soups, and sauces.

Depending on the variety, ranging from pungent and sharp to savory or mild and sweet (sweet onions). Pungency is caused by sulfur-containing compounds.

Base aromatic for almost all savory dishes; key component in dishes like onion tart, French onion soup, or stews.

1. Bulb
2. Green shoots (leaves)
3. Flowers (as garnish)

1. Dried, papery outer skins
2. Root plate (technically edible but woody and earthy)

Non-toxic and highly beneficial for humans. Note: Allium species are highly toxic to domestic animals (dogs, cats, horses) due to disulfides, which destroy red blood cells.

Fully possible and common (e.g., in salads or burgers). May cause stomach irritation or flatulence in sensitive individuals.

1. Selection of healthy, true-to-type bulbs in the late summer of the first year.
2. Frost-free overwintering of the selected mother bulbs at cool temperatures.
3. Replanting the bulbs in the following spring (March/April).
4. Supporting the heavy flower scapes with stakes.
5. Harvesting the seed heads as soon as the capsules open and black seeds become visible.
6. Curing in a dry place, followed by threshing and cleaning the seeds.

Cross-pollinates readily with all other varieties of Allium cepa (including shallots). Does not cross with garlic (Allium sativum) or chives (Allium schoenoprasum), but caution is advised near Allium fistulosum.

To prevent inbreeding depression and maintain varietal stability, seeds should be aggregated from a minimum of 20 to 50 distinct parent plants.

Onions (Allium cepa) are herbaceous biennial vegetable crops and do not develop woody tissues. Therefore, rootstocks and training systems are not applicable to this crop.

In their second year, the large, spherical flower umbels attract numerous wild bees, honeybees, and hoverflies. When grown as an annual for bulb harvest, they offer no value to pollinators.

From July onwards, gradually cease watering to ensure proper curing and long storage potential.

Deeply loosen beds the previous autumn and work in mature compost; strictly avoid fresh manure in spring.

Bed preparation and planting onion sets in March or April.

Hoeing, weed control, pest monitoring, and harvesting starting in August.