How to Grow Rossa di Milano
Allium cepa
Rossa di Milano is a celebrated heirloom onion variety prized for its mild flavor and deep red skin. Gardeners grow this cool-season crop to enjoy fresh bulbs in salads or cooked dishes throughout the cooler months of the year.
📷 Wikipedia: OnionStarting Rossa di Milano: indoors or direct sow?
🌾 Sow directly in the garden — Rossa di Milano is not usually started indoors.
This variety is best started directly in the garden rather than indoors; simply sow seeds outdoors 2 to 6 weeks before your last frost date.
Soil, care & harvest
Prepare loose, well-draining soil with a pH between 6.0 and 7.0. Sow seeds directly outdoors 2 to 6 weeks before your last spring frost date, as this is a cool-season crop that tolerates light frosts. Press seeds into the soil at a depth of about half an inch. Expect germination in 7 to 14 days under these conditions.
Space seedlings 4 to 6 inches apart once they emerge. While onions generally do not require trellising, ensure your plants have room for bulb development. Water consistently to provide about one inch per week, keeping the soil evenly moist but not waterlogged. Apply a light mulch around the base to retain moisture and suppress weeds.
Watch for onion thrips, aphids, and wireworms; monitor plants closely and remove affected leaves or use organic controls if infestations appear. Prevent fungal issues like Fusarium basal rot by ensuring good air circulation and avoiding overhead watering. Harvest your bulbs approximately 100 days after sowing when the tops begin to yellow and fall over.
When to Plant Rossa di Milano
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | — | June – July | September |
| Zone 2 | — | May – July | August – September |
| Zone 3 | — | May – June | August – October |
| Zone 4 | — | April – June | August – October |
| Zone 5 | — | April – May | July – November |
| Zone 6 | — | April – May | July – November |
| Zone 7 | — | March – May | June – November |
| Zone 8 | — | March – April | June – December |
| Zone 9 | — | February – March | May – December |
| Zone 10 | — | January – March | April – December |
| Zone 11 | — | January – February | March – December |
| Zone 12 | — | January – February | March – December |
| Zone 13 | — | January – February | March – December |
Companion Plants for Rossa di Milano
✓ Good companions
Onions deter cabbage worms, flea beetles, and aphids from cabbage family plants
Onions deter carrot flies while carrots help break up soil for bulb development
Alliums repel aphids and rabbits that damage lettuce crops
Both repel nematodes and create a pest-deterrent barrier when planted together
Onions deter aphids and may improve pepper flavor and growth
Alliums repel aphids, thrips, and may reduce black spot fungal issues
Alliums repel slugs and aphids while potentially improving berry flavor
Alliums repel aphids and spider mites that commonly attack tomatoes
✗ Keep away from
Allelopathic compounds from onions can reduce asparagus spear production
Alliums can inhibit nitrogen fixation by rhizobia bacteria in legume roots
Onions release compounds that stunt pea growth and reduce pod production
Nutrition Facts
Per 100g serving (USDA FoodData Central)
