Bunium bulbocastanum
Great pignut
Common names: Earthnut
At a glance
- Light
- Full sun
- Spacing
- 15 cm, rows 25 cm
- Lifespan
- Perennial
- Sowing
- Oct–Nov
- Harvest
- Sep–Oct
- Hardiness
- Hardy down to −15 °C
- Water need
- Medium
- Origin
- Native to Germany
Photo: Jan Kops · Public Domain · Source
Description
Great pignut (Bunium bulbocastanum) is a tuberous umbellifer and a true rarity in the vegetable garden. Underground it forms a hazelnut- to walnut-sized tuber with a chestnut-like flavor, eaten raw or cooked. Its fine, cumin-like seeds are used as a spicy seasoning for bread, soups, and stews. The plant requires patience: it takes two to three years for the tubers to grow to a substantial size before they can be harvested.
Care instructions
Plant in loose, deep soil to allow the tuber to develop freely. Sow directly outdoors in autumn, around mid-October (week 42), as the seeds need a cold stimulus to germinate. Keep the site moderately moist but avoid waterlogging, and mulch regularly in the first months to suppress weeds, as young seedlings struggle to compete. Mark the planting area well, as the perennial plant is disturbed easily during digging or turning. Harvest earliest in the second autumn, but usually only in the third autumn after the foliage has died back.
The care notes were machine-translated from German.
Garden year
SowingOct–Nov
HarvestSep–Oct
Germination
- Soil temperature
- from 2 °C, ideally 10 °C
- Days to sprout
- 30 to 90 days
- Light
- Sprouts in light or dark
- Sowing depth
- 1 cm
- How to start
- Sow straight into the bed
Soil & site
Soil pH
Soil type
well-drained, lime-loving, sandy, dry
The great pignut likes deep, loose soil in which its small tubers can develop unhindered. Calcareous, warm sites with good drainage suit its origin in dry meadows and verges. It tolerates waterlogging poorly, as this makes the tubers rot. A poor to moderate nutrient level is quite enough for it.
As a member of the umbellifer family, the great pignut shares diseases with carrot and parsnip, so allow a gap of several years from these relatives. Since it is a perennial and stays in the same place for years anyway, crop rotation mainly concerns its neighbours in the bed.
Feeding
Light feeder
As an undemanding wild plant, the great pignut needs hardly any feeding. A thin application of compost in spring before new growth is enough as a gentle top-up of nutrients. Soil that is too rich in nutrients encourages lush green leaves rather than strong tubers, so it is better to stay restrained.
Overwintering
After the seeds ripen in summer, the great pignut dies back above ground and survives protected in the soil as a tuber. It is hardy and needs no extra protection; a border of mulch just keeps the soil slightly more evenly moist. In spring it reliably sprouts again from the tuber.
Propagation
Methods
- From seed
- Division
Propagation is easiest with freshly harvested seed, sown directly after ripening in summer or in autumn, because viability declines quickly. Germination itself often drags on over the winter and depends on the weather, so bring some patience. Alternatively, when digging up established plants, small daughter tubers can be separated and planted in a new spot. A warm, chalky position makes it easier for both methods to get started.
Companion planting
Good neighbors
amaryllis family (Amaryllidaceae)
Umbellifers and alliums confuse each other's pests (carrot fly, onion fly).
For example GarlicOnionLeekChivesWild daffodilRocambole and 12 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
daisy family (Asteraceae)
Calendula and Tagetes next to carrots keep the carrot fly away with their scent.
For example Head lettuceFrench marigoldCalendulaSunflowerButterhead lettuceCommon coneflower and 73 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
cabbage family (Brassicaceae)
You can pair celery and dill with all Brassicaceae because they repel the cabbage whitefly with their scent, a proven companion.
For example White cabbageKohlrabiRadishKalebroccolicauliflower and 41 more species in the catalogue
Source: Bio-Gärtnerei Mixed-culture Practice
legume family (Fabaceae)
Peas and beans provide carrot and celery with nitrogen and grow as shallow-rooted plants without competition next to each other.
For example PeaBush beanPole beanBroad beanSnow peaWrinkled pea and 36 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For your garden
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