How to Grow Purple Top Walla Walla
Allium cepa 'Purple Top Walla Walla'
Purple Top Walla Walla is a beloved heirloom onion variety prized for its mild flavor and attractive purple-tinged bulbs. Gardeners cultivate this cool-season crop for its reliability in cooler climates and its suitability for both garden beds and containers.
📷 Wikimedia CommonsStarting Purple Top Walla Walla: indoors or direct sow?
🌾 Sow directly in the garden — Purple Top Walla Walla is not usually started indoors.
You can direct-sow seeds outdoors two to six weeks before the last frost or start indoors during this same window and transplant seedlings once they are sturdy enough to handle outdoor conditions.
Soil, care & harvest
Prepare loose, well-draining soil with a pH between 6.0 and 7.0 to encourage healthy root development. Sow seeds indoors or direct-sow outdoors two to six weeks before your last spring frost date. Press seeds gently into the soil at a depth of about one-quarter inch. Germination typically occurs within seven to fourteen days, after which seedlings can be hardened off for outdoor placement.
Space plants four to six inches apart in rows spaced eighteen inches wide to ensure proper air circulation and bulb size. Provide consistent moisture, aiming for one inch of water per week, especially during early growth, but reduce watering as bulbs mature. Apply a light layer of mulch to retain soil moisture and suppress weeds, avoiding piling it directly against the necks.
Monitor for onion thrips, maggot larvae, and cutworms by inspecting foliage regularly; use row covers or organic sprays if infestations occur. Watch for downy mildew, purple blotch, and pink root, ensuring good airflow to prevent fungal issues. Harvest bulbs when tops fall over naturally, usually taking 125 to 300 days from sowing depending on variety maturity.
When to Plant Purple Top Walla Walla
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | — | June – July | December – September |
| Zone 2 | — | May – July | December – September |
| Zone 3 | — | May – June | December – October |
| Zone 4 | — | April – June | November – October |
| Zone 5 | — | April – May | November |
| Zone 6 | — | April – May | November |
| Zone 7 | — | March – May | October – November |
| Zone 8 | — | March – April | October – December |
| Zone 9 | — | February – March | September – December |
| Zone 10 | — | January – March | August – December |
| Zone 11 | — | January – February | July – December |
| Zone 12 | — | January – February | July – December |
| Zone 13 | — | January – February | July – December |
Companion Plants for Purple Top Walla Walla
✓ Good companions
Onions repel cabbage worms, aphids, and flea beetles
Onions repel carrot fly while carrots help break up soil for onion bulbs
Onions provide natural pest deterrent while lettuce doesn't compete for space
Both plants repel nematodes and various garden pests when grown together
Onions help repel aphids and other soft-bodied insects that damage peppers
Onions help repel aphids, thrips, and may reduce black spot disease
Onions deter slugs, aphids, and other pests that commonly attack strawberry plants
Onions deter aphids, spider mites, and hornworms from tomato plants
✗ Keep away from
Onions can inhibit asparagus growth and reduce spear production
Onions can inhibit nitrogen fixation in legumes and stunt their growth
Allelopathic compounds from onions interfere with pea plant development
Both plants compete for similar nutrients and can inhibit each other's growth
Nutrition Facts
Per 100g serving (USDA FoodData Central)
