How to Grow Radish in Australia

Radishes are the perfect beginner vegetable and the ideal crop to fill empty spaces between slower-growing vegetables. At 25–35 days to harvest, they can be sown, grown, and harvested in the time it takes a carrot to germinate properly.

Sow seeds 1cm deep, 5cm apart in rows 20cm apart. For gap-filling, simply broadcast seeds in any empty area and thin as needed. Radishes prefer cool weather and will bolt to seed rapidly in heat above 25°C — succession sow every 2–3 weeks through autumn, winter, and spring.

Small varieties include 'Sparkler' (red and white, 25 days), 'French Breakfast' (long, mild, 30 days), and 'Cherry Belle' (round, classic). Daikon radishes are large, mild white radishes that take 60–70 days and are excellent for Asian cooking; they also perform brilliantly as a 'tillage radish', breaking up compacted subsoil in raised beds.

The key to good radishes is consistent moisture and cool temperatures. In heat or drought, they produce pithy, hollow, hot roots. Never let the soil dry out. A mulch of fine compost helps maintain moisture.

Radishes are outstanding as companion plants. Interplant them with carrots — radishes germinate quickly and break up the soil, making it easier for slow-germinating carrot seedlings to push through. By the time radishes are harvested, the carrots are well established.