How to grow Radish Sprouts in New Zealand
Radish sprouts and microgreens give a peppery, crunchy kick to salads, sandwiches and stir-fries, and they are one of the quickest crops there is, ready in about five to eight days. Grow them in a sprouting jar on the bench or on a tray of mix on the windowsill, indoors all year round.
📖 Our full guide: How to Grow Radish Sprouts in New Zealand
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | All year | |
| Auckland | All year | |
| Waikato & Bay of Plenty | All year | |
| Central North Island | All year | |
| Wellington & Lower North Island | All year | |
| Nelson & Marlborough | All year | |
| Canterbury | All year | |
| Otago & Southland | All year | |
| Central Otago | All year |
Not to be confused with: Radish grown for its roots, which is the same plant left to grow on in the garden for four to six weeks.
Where to plant
Sprouts grow in a jar on the kitchen bench, in a cool, ventilated spot out of direct sunlight. Microgreens grow in a shallow tray of seed-raising or vegetable mix on a bright windowsill or bench. Both can be grown indoors at any time of year, in any part of the country.
Choosing a variety
- Buy seed sold for sprouting or microgreens, which is untreated and intended for eating. Never sprout seed from a garden packet that may have been treated with fungicide.
- Red-stemmed radish types such as Rambo or China Rose give colourful microgreens; daikon types are mild and crisp.
How to grow them
- For sprouts, soak a spoonful of seed in clean water for a few hours, drain, and put it in a sprouting jar with a mesh lid.
- Rinse and drain the seed twice a day, leaving the jar tilted so it drains fully. Most sprouts are ready in under a week.
- For microgreens, fill a tray with moist seed-raising mix, scatter seed evenly but not too thickly, cover lightly, and keep moist.
- Good air flow matters: thick sowing and poor ventilation cause mould and rot.
- Sow a new batch every few days for a continuous supply.
Watering and feeding
Sprouts need rinsing with clean water twice a day and must drain well in between; standing water lets bacteria and mould multiply. Microgreens need the mix kept just moist; water gently from below or with a fine spray so the seedlings are not flattened.
Harvesting
Eat sprouts when the first leaves open, after about five days. Cut microgreens with scissors once the first leaves have opened, at about 3 to 5 cm tall, just above the mix. Rinse and use straight away, or keep them in the fridge, where sprouts stay fresh for up to 10 to 14 days.
New Zealand Food Safety advises that raw sprouts are a high-risk food, because bacteria such as Salmonella, E. coli and Listeria on a single seed can spread in the warm, moist conditions. Do not serve raw sprouts to babies, young children, pregnant women, the frail elderly or anyone with a weakened immune system; cooking them thoroughly makes them safe.
Companion planting
Radish sprouts are grown indoors on their own, but they mix well with other sprouts and microgreens.
Good companions
- Broccoli Sprouts Another quick, peppery sprout that can share a jar or tray rotation.
- Sunflower Microgreens Nutty, crunchy microgreens that pair well in salads.
Pests and diseases
The problems with sprouts and microgreens are mould and rot from poor air flow or overwatering.
Radish Sprouts is rarely troubled by pests.
Diseases to watch for
- Damping off Seedlings collapse at the base in patches. Sow thinner, improve air flow and water less.
- Mould Grey or furry growth over the seed. Rinse more often, drain well and keep the jar out of the sun. Note that the fine white root hairs of healthy radish sprouts are not mould.
Common questions
How long do radish sprouts take?
About five to eight days, one of the fastest crops you can grow.
Are raw sprouts safe to eat?
New Zealand Food Safety rates raw sprouts as a high-risk food. Most people can eat them, but they should not be served raw to babies, young children, pregnant women, the frail elderly or anyone with a weakened immune system. Cooking them thoroughly makes them safe.
Is the white fuzz on my radish sprouts mould?
Usually not. Radish sprouts grow fine white root hairs that look fuzzy, especially just before rinsing. Grey, slimy or smelly growth is mould, and that batch should be thrown out.
What is the difference between sprouts and microgreens?
Sprouts are germinated in water and eaten whole, roots and all, within a few days. Microgreens are grown in mix with light and cut above the soil once the first leaves open.
Can I use ordinary radish seed?
Use seed sold for sprouting or microgreens. Garden seed may be treated with fungicide and is not meant for eating.
Sources we checked: Tui: Mini magic, growing microgreens at home; Kings Seeds: Getting the best from your sprouts; NZ Food Safety (MPI): Raw seed sprouts are a risk to eat.