very easy · windowsill
How to grow radish
The fastest root you can grow — sowing to crunchy radish in about four weeks. Ideal for keeping children (and impatient adults) interested.
Raphanus sativus · Brassicaceae
Why bother
It is genuinely quick and needs no special care, so it delivers a real harvest before enthusiasm runs out. A brilliant first vegetable.
What it needs
- Light
- 4+ hours of sun.
- Water
- Keep consistently moist; erratic watering splits the roots.
- Soil
- Light, stone-free compost at least 15cm deep so the roots swell freely.
- Temperature
- Cool-season, roughly 10-22C.
- Container
- A 15cm-deep pot or trough; sow direct, they do not transplant.
- Time to harvest
- 4 weeks from sowing.
- Best season to start
- Sow spring to autumn in short successions; too much summer heat makes them woody.
Step by step
Day 0
Sow direct
Sow 1cm deep and 2-3cm apart in a deep pot. Water in.
Week 1
Thin early
Thin to 3cm as soon as the first leaves show, so roots have room to swell.
Week 4
Pull young
Harvest as soon as roots reach 2-3cm across; sow another short row.
What usually goes wrong
All leaf, no root
Cause: Sown too close, too little light, or too much nitrogen.
Fix: Thin to 3cm apart and give them the brightest spot you have.
Roots split or go hollow
Cause: Watering after a dry spell, or left in the ground too long.
Fix: Water evenly and pull them young — radishes wait for no one.
Grows well beside
Cut-and-come-again lettuce, Spring onions
Before you eat anything you grow: be certain of the identification. This guide describes radish specifically — it is not a way to confirm that an unknown plant is safe. Never eat a plant on the strength of an app alone.