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When to Plant Onion in Zone 13A

USDA Zone

13A

Cities Covered

2

Avg Last Frost

Thursday, January 1, 2026

Plant Type

Indoor Start

📅 Planting Calendar for Zone 13A

Start Seeds Indoors Thursday, November 6, 2025
Transplant Outdoors Thursday, January 15, 2026

Pro Tip: Start Onion seeds indoors 8 weeks before your last frost date for best results.

🌿 Plant Details

Scientific Name Allium cepa
Days to Maturity 100 days
Sun Requirements Full Sun (6+ hours)
Plant Spacing 4" apart

Cities in Zone 13A

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Growing Onion in USDA Zone 13A

Onion (Allium cepa) grows well in USDA Hardiness Zone 13A. This zone includes cities like Keauhou, M C B H Kaneohe Bay.

The average last frost date for Zone 13A is around Thursday, January 1, 2026. For best results, start your Onion seeds indoors around Thursday, November 6, 2025, then transplant outdoors around Thursday, January 15, 2026.

Expect to harvest your Onion approximately 100 days after planting.