SproutSmart
SproutSmart Intelligent Garden Sowing

Long Black

Radish

Planting Schedule

Add Long Black to your garden to build a schedule and get reminders.
Botanical illustration of Long Black
55d to harvest

Sink your senses into Long Black’s velvety, inky skin—an elegant black radish that feels almost lacquered in the hand. Beneath the dark exterior lies crisp, bright flesh with a clean, peppery snap that mellows beautifully when allowed to reach full size at about 55 days. Ideal for bold fresh slices and striking grated accents, Long Black also shines in quick pickling for a dramatic color contrast and lively bite.

Crop Dates

MilestoneDate
Start IndoorsDirect Sow
Last FrostMar 23rd
Transplant / Sow OutdoorsMar 23rd
Harvest BeginsMay 17th
Harvest EndsNov 12th

Crop Details

TraitValue
Days to Maturity55
Sun RequirementsFull SunFull sun
Growth HabitTaproot
Support NeededNone
Planting DepthNormal
Germination Temp (°F)60
Min Soil Temp (°F)45
Min Night Temp (°F)28
Harden Off (days)Not Required

Frequently Asked Questions


How often should I water Long Black radishes during their main growth phase to form a good root?
During root bulking (roughly weeks 3–6), keep the soil evenly moist but not soggy—about 1 inch of water per week total, adjusted for heat and rainfall. Water deeply when the top 1 inch of soil starts to dry, since radishes that swing between dry and wet can become woody or cracked. Mulch lightly to reduce moisture swings while avoiding a thick layer that stays wet.
How can I tell when Long Black radish (Raphanus sativus) is ready to harvest?
Harvest around 55 days, but confirm by checking the shoulder of the root at the soil surface. When the root is firm and roughly 1.5–2.5 inches wide (and the skin looks fully colored), pull it before it gets hollow or pithy. If you see the leaves fading and the root feels overly firm/woody, harvest immediately to preserve eating quality.
Botanical illustration of Long Black

Sink your senses into Long Black’s velvety, inky skin—an elegant black radish that feels almost lacquered in the hand. Beneath the dark exterior lies crisp, bright flesh with a clean, peppery snap that mellows beautifully when allowed to reach full size at about 55 days. Ideal for bold fresh slices and striking grated accents, Long Black also shines in quick pickling for a dramatic color contrast and lively bite.