How to Grow Purple Plum Radish
Raphanus sativus 'Purple Plum'
Purple Plum Radish is a fast-growing root vegetable prized for its vibrant color and mild, sweet flavor. Gardeners value this cool-season crop for its quick harvest time and ability to thrive in cooler temperatures where many other vegetables struggle.
📷 Wikimedia CommonsStarting Purple Plum Radish: indoors or direct sow?
🌾 Sow directly in the garden — Purple Plum Radish is not usually started indoors.
Direct sow seeds outdoors rather than starting indoors, as transplanting can shock these delicate root vegetables and lead to forked growth.
Soil, care & harvest
Prepare loose, well-draining soil with a pH between 6.0 and 7.0 to ensure healthy root development. As a cool-season crop, sow seeds directly outdoors 2 to 6 weeks before your last spring frost date. Press seeds gently into the soil at a depth of about 1/4 inch. You can expect germination within 4 to 7 days under these conditions.
Space plants 1 to 2 inches apart in rows spaced 3 to 6 inches wide to prevent overcrowding, which stunts root growth. Keep the soil consistently moist with about half an inch of water per week, but avoid soaking the roots. Apply a light layer of mulch around the base to retain moisture and suppress weeds without touching the foliage.
Watch for flea beetles, aphids, and cabbage root maggots; use row covers or insecticidal soap if infestations occur. Clubroot and downy mildew are manageable with proper spacing and good airflow. Harvest your radishes when they reach maturity in just 25 to 30 days by gently pulling them from the soil before the roots become woody.
When to Plant Purple Plum Radish
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | — | June – July | June – September |
| Zone 2 | — | May – July | June – September |
| Zone 3 | — | May – June | May – October |
| Zone 4 | — | April – June | May – October |
| Zone 5 | — | April – May | May – November |
| Zone 6 | — | April – May | April – November |
| Zone 7 | — | March – May | April – November |
| Zone 8 | — | March – April | March – December |
| Zone 9 | — | February – March | February – December |
| Zone 10 | — | January – March | February – December |
| Zone 11 | — | January – February | January – December |
| Zone 12 | — | January – February | January – December |
| Zone 13 | — | January – February | January – December |
Companion Plants for Purple Plum Radish
✓ Good companions
Root zones don't compete as carrots grow deeper, and radishes help break up soil for carrot growth
Natural pest deterrent that repels aphids and flea beetles that commonly attack radishes
Radishes help deter cucumber beetles and can be harvested before cucumbers need full space
Quick-growing leaves provide shade for radish roots and help retain soil moisture
Repels root maggots and other soil pests that can damage radish roots
Acts as trap crop for flea beetles and aphids, protecting radish foliage
Fixes nitrogen in soil and provides natural support structure without competing for root space
Cool-season companion that shares similar growing conditions and harvest timing
✗ Keep away from
Both are brassicas competing for same nutrients and susceptible to similar pests and diseases
Allelopathic compounds inhibit radish germination and early growth
Same plant family with identical pest and disease issues, creating concentrated infestations
Nutrition Facts
Per 100g serving (USDA FoodData Central)
