Other names
black spanish radish, winter radish
Botanical name
Raphanus sativus var. niger
Family / Genus
Brassicaceae / Raphanus
Plant category
Root and tuber vegetables
Black radish, like other winter radish varieties, belongs to the garden radishes. It has some of the best storage qualities, partly thanks to its firm, rough skin.
Facts and figures
Light requirements
Sun / partial shade
Nutrient requirements
Medium feeder
Difficulty level
Easy
Culture (according to Gertrud Franck)
B - late, C - low growth, short growing period
Culture (according to Sister C. Weinrich)
Companion crop
Growing period
90 days
Row spacing
25 cm
Plant spacing
10 cm
Growth height
30 - 40 cm
Sowing depth
1 cm
Germination temperature (minimum)
8 °C
Germination temperature (optimal)
18 - 25 °C
Germination type
Light
Planting & harvest times of Black radish
1
2
3
4
5
6
7
8
9
10
11
12
Direct sowing
Harvest
Direct sowing from Mid June to Mid August. After a growing period of 90 days, harvest can begin around Mid September and continues until Late November.
Good and bad companions of Black radish
Good neighbours
Bad neighbours
Courgette
In companion planting, radish is considered a poor neighbour for courgettes and cucumbers. Small summer radishes are not affected.
Evidence quality: moderate
Evidence: Long-standing companion planting practice (e.g. Gertrud Franck, Schwester C. Weinrich)
Cucumber
Large radishes are said to make cucumber flowers sterile in hot, dry early summers. Small radishes do not.
Evidence quality: moderate
Evidence: Long-standing companion planting practice (e.g. Gertrud Franck, Schwester C. Weinrich), Guidebooks, companion planting charts, tradition
Reasons:
- Allelopathy, growth inhibition
Melothria
Winter radishes are said to make cucumber flowers sterile. This is carried over to the related Melothria but has not been observed there.
Evidence quality: limited
Evidence: Long-standing companion planting practice (e.g. Gertrud Franck, Schwester C. Weinrich), Guidebooks, companion planting charts, tradition, Derived from plant family or pathogen, pair not directly documented
Preliminary assessment, we're still researching.
Reasons:
- Allelopathy, growth inhibition
Very bad neighbours
Predecessors and successors of Black radish
Bad predecessors
Broccoli
Black radish is also a brassica and shares clubroot and cabbage root fly with broccoli. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Brussels sprouts
Rotation break: 3 years
Cauliflower
Black radish is also a brassica and shares clubroot and cabbage root fly with cauliflower. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Garden cress
Rotation break: 3 years
Horseradish
Rotation break: 3 years
Kale
Black radish is also a brassica and shares clubroot and cabbage root fly with kale. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Swede
Rotation break: 3 years
Winter cress
Rotation break: 3 years
Very bad predecessors
Mustard
Both are brassicas. Clubroot resting spores survive up to 20 years in the soil, so a 4 to 5 year break is needed.
Rotation break: 4 years
Oil radish
Rotation break: 3 years
Radish
Radishes and winter radishes are the same species and share black root and clubroot. Wait four years before using the same bed again.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
- Self-incompatibility
Good successors
Bad successors
Batavia lettuce
Rotation break: 3 years
Broccoli
Black radish is also a brassica and shares clubroot and cabbage root fly with broccoli. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Brussels sprouts
Rotation break: 3 years
Butterhead lettuce
Rotation break: 3 years
Cauliflower
Black radish is also a brassica and shares clubroot and cabbage root fly with cauliflower. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Garden cress
Rotation break: 3 years
Horseradish
Rotation break: 3 years
Iceberg lettuce
Rotation break: 3 years
Kale
Black radish is also a brassica and shares clubroot and cabbage root fly with kale. Keep four years apart.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
Lollo biando / Lollo rosso
Rotation break: 3 years
Oak leaf lettuce
Rotation break: 3 years
Red cabbage
Rotation break: 3 years
Romaine lettuce
Rotation break: 3 years
Romanesco
Rotation break: 3 years
Spinach
Rotation break: 3 years
Swede
Rotation break: 3 years
White cabbage
Rotation break: 3 years
Winter cress
Rotation break: 3 years
Very bad successors
Mustard
Both are brassicas. Clubroot resting spores survive up to 20 years in the soil, so a 4 to 5 year break is needed.
Rotation break: 4 years
Oil radish
Rotation break: 3 years
Radish
Radishes and winter radishes are the same species and share black root and clubroot. Wait four years before using the same bed again.
Rotation break: 4 years
Evidence quality: good
Evidence: Advisory service, research institute, Specialist book
Reasons:
- Shared soil-borne pathogen
- Self-incompatibility
Diseases and pests
Susceptible to
Alternaria leaf spot of brassicas
Black root of radish
Black rot(low susceptibility)
Cabbage root fly(high susceptibility)
Clubroot
Diamondback moth
Downy mildew of brassicas
Flea beetles
Swede midge
White rust
Harvest and processing
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