Radishes can be grown in just about any kind of container. Proper drainage and soil depth are critical, however. Radishes are susceptible to root rot if over-watered, so the container should have plenty of drainage holes. Most radishes need about eight to twelve inches of soil. Some, like daikon, can grow to 18 inches or more and may not be suitable for growing in containers.
The Right Soil
Container growing means careful attention to soil. Use rock phosphate or bone meal amendments for phosphorus. Don’t add additional nitrogen, as it promotes leafy growth rather than root development. Good quality potting soil or garden soil well mixed with aged manure, compost or leaf mold are excellent choices. Use fresh soil for each crop of radishes to ensure adequate nutrients.
It’s easy to over-water radishes in containers, which may result in seed or root rot. Friable, sandy soil that is rich in humus will allow best drainage. Soil should be evenly moist. Plunge a thin stake into the soil to check moisture levels before watering. Make sure pots are draining freely. Clay pots may be the best choice in humid areas; plastic holds moisture in the soil.
Varieties for Containers
Most radish varieties are suitable for containers. Choose classic round globes or shorter carrot-shaped forms. Check size at maturity as longer roots can be a problem. Daikon can grow 14 to 18 inches long, but White Icicle can be container-grown. These are good choices:
- Pink Beauty – 25 days
- Sparkler – 25 days
- Crimson Giant – 30 days
- French Breakfast – 30 days
- White Icicle – 35 days
Spacing and Thinning
When growing in containers, pay close attention to spacing. Most standard varieties need an inch between plants. An additional half inch may be better in the long run for best growth. Spacing is easy in rectangular containers, but in round containers, be sure the plants aren’t too close to the container wall. Thin the seedlings with a pair of sharp scissors to prevent root damage.
Growing radishes in containers allows you to move them for best conditions. If growing in the low light of fall or winter, you can site containers for maximum daylight. Although radishes are cold-hardy, you can move containers into the garage if extreme conditions are predicted. Containers can also be moved into the shade on hot summer afternoons or under a roof overhang during heavy rains.