How to grow Radish in New Zealand
Radishes are the fastest crop in the vegetable garden, ready to pull four to six weeks after sowing, which makes them perfect for children and impatient gardeners. Sow little and often into loose, moist soil in full sun, and pick them young before they turn woody and hot.
📖 Our full guide: How to Grow Radish in New Zealand
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | August to April | |
| Auckland | August to April | |
| Waikato & Bay of Plenty | August to April | |
| Central North Island | August to April | |
| Wellington & Lower North Island | August to April | |
| Nelson & Marlborough | August to April | |
| Canterbury | August to April | |
| Otago & Southland | September to April | Start spring sowings in Sep; the soil is too cold before then. |
| Central Otago | September to March | Start spring sowings in Sep; the soil is too cold before then. Make the last sowing in Mar so the crop is ready before winter growth stops. |
Not to be confused with: Daikon, the long white Asian radish, which takes longer and is grown in the cooler months.
Where to plant
Radishes like full sun and loose, well-worked, free-draining soil. Compacted, wet or stony soil, or bits of bark and sticks, give small and misshapen roots. In the heat of summer a spot with light afternoon shade slows bolting.
- Northland to Canterbury: sow from late winter through to autumn, avoiding the coldest months.
- Otago and Southland: start spring sowings in September, when the soil has warmed.
- Central Otago: sow from September to March, so the last crop is ready before winter growth stops.
Choosing a variety
- Round red types such as Red Cherry, Cherry Belle and Red Globe are quick and crisp.
- French Breakfast has long red roots with white tips and a mild flavour.
- Easter Egg gives a mix of red, pink, purple and white roots.
- White Icicle has long, white, mild roots.
- Winter radishes such as daikon and watermelon radish are bigger, take 8 to 10 weeks or more, and are sown for autumn and winter.
How to plant
- Work the soil until it is fine and loose, removing stones and sticks.
- Make shallow rows about 30 cm apart and water them.
- Sow seeds 3 to 5 cm apart, cover lightly and press down gently.
- Water lightly and regularly until the seedlings are up, then thin any that are crowded.
- Sow a short row every two or three weeks for a steady supply.
Watering and feeding
Keep the soil evenly moist. Radishes that dry out grow slowly and turn woody, hot and split. Feed lightly with a liquid fertiliser if the soil is poor; too much nitrogen gives leaves instead of roots.
Pruning and care through the year
- Thin seedlings early so each radish has room to swell.
- Keep the bed weed free and watch for slugs and snails on young seedlings.
- Cover seedlings with fine insect mesh if flea beetles riddle the leaves with small holes.
Harvesting
Pull radishes as soon as they are big enough to eat, often marble to small walnut size for round types. Do not leave them in the ground, as they quickly turn woody, tough and hot and then run to seed. The young leaves are edible too, and the green seed pods of bolted plants make a crunchy snack.
Growing in pots
Radishes grow well in pots and troughs at least 20 to 25 cm deep, filled with a loose, free-draining mix. Sow direct, thin early, and keep the mix evenly moist.
Companion planting
Radishes are quick and small, so they fit between slower crops and are out of the way before those crops need the space.
Good companions
- Lettuce Shares the bed and is picked over a similar time.
- Carrot Radishes sown with carrot seed mark the row and break the soil crust, and are pulled before the carrots need the room.
Keep apart
Avoid planting these close to radish.
- Hyssop (a bushy flowering herb whose blue flowers draw bees)
Pests and diseases
Radishes are quick enough to outrun most problems, but a few pests still find them.
Pests to watch for
- Flea beetle Tiny round holes peppering the seedling leaves.
- Slugs Seedlings eaten off overnight after rain.
- White butterfly Green caterpillars on the leaves of slower winter radishes.
Diseases to watch for
- Clubroot Stunted plants with swollen, distorted roots. Rotate with non-brassica crops.
Common questions
How long do radishes take to grow?
Most are ready four to six weeks after sowing. Winter varieties such as daikon take eight to ten weeks or more.
Why are my radishes all leaves and no root?
Usually crowding, too much shade, too much nitrogen, or very hot weather. Thin seedlings early, grow them in sun, and feed lightly.
Why are my radishes hot and woody?
They were left in the ground too long or dried out. Pick them young and keep the soil evenly moist.
Can I transplant radish seedlings?
It is best not to. Radishes do not transplant well; damaged roots give misshapen crops. Sow them where they are to grow.
Why are my radishes small or misshapen?
Compacted soil, overcrowding, uneven watering, or stones and sticks in the soil. Sow into loose, well-prepared soil, thin early and water evenly.
Can I grow radishes in a pot?
Yes, in a pot or trough at least 20 to 25 cm deep with a free-draining mix.
Sources we checked: Tui: Radish growing guide; Yates NZ: How to grow radishes; Kings Seeds: Radish range.