Black radish

Black radish: plant 10 cm (3.9 in) apart in the row and 30 cm (12 in) between rows, 9 per square. No known bad neighbours.

Key facts

Spacing in the row	10 cm (3.9 in)
Between rows	30 cm (12 in)
In a 30 cm (1 ft) square	9 per square
Sun	Full sun, 6–8 hours a day
Root depth	40 cm (16 in)
Height when grown	30 cm (12 in)
Crop rotation group	Cabbage family
Support	None needed

Sowing and germination

How it is started	Sown straight into the bed
Seeds per hole	3
Plants kept after thinning	1
Seeds per metre of row	30
Sowing depth	1.5 cm (0.6 in)
Soil temperature	from 4 °C, best 18–29 °C
Days to emerge	3–6 days
Light while germinating	Needs darkness, cover well
Before sowing	nothing needed
When to sow	Outdoors before the last frost; soil at least 7 °C

From seedling to plant

Pricking out	sown where it grows
Takes transplanting	Badly, sow where it grows
Life cycle	Biennial, harvested in its first year
Cold tolerance	Takes a light frost → hardy, takes hard frost
Soil	Light, sandy, free draining, pH 6–7
In a pot	10 L, 30 cm (11.8 in)
Watering	Water when the soil is dry two fingers down; while roots swell
Feeding	Little; at planting
Support and training	None needed

Harvest and planning

Days to first harvest	60–80 days, from sowing
Ready when	The shoulder shows at the right size
Harvest window	All at once, 3–6 weeks
Sow again every	21 days
Typical yield	3–5 kg per m²
Botanical family	Brassicaceae
Watch out for	Flea beetles, clubroot, slugs and snails

Plan Black radish in your garden

Open the free planner, drop Black radish onto a bed and see how many plants fit.

Start Planning Your Garden

Sowing and harvest

Sow outdoors	Jun–Jul
Harvest	Sep–Nov

My dates for this crop

My country Last spring frost where I live

Give the date once and this page, the sowing calendar and the planner all follow it.

Months for a temperate climate: about a month later in the north and a month earlier in the south. Give your own last frost date for exact dates.

What to plant next to Black radish →

From the same family

Plants of the Brassicaceae family share diseases and pests, so they follow each other in the rotation only after a break.

Grown much the same way

Crops that need about the same room and care, from another family.

Sources

The values on this page marked as checked come from these sources: spacing, sowing depth, germination, soil, timing and safety notes, each against the source named here.

Soil temperature conditions for vegetable seed germination (J.F. Harrington; reviewed 2024) — Oregon State University Extension for: days to emerge, soil temperature; checked 2026-10-30
Soil Temperature Conditions for Vegetable Seed Germination (GN 154, after J.F. Harrington, UC Davis) — UC Cooperative Extension, UC ANR for: soil temperature; checked 2026-10-30

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