Onion Planting Guide — All Zones
Allium cepa
Last updated: Apr 29, 2026Quick Facts
Sunlight
☀️ Full Sun
Water Needs
💧💧 Moderate
Spacing
6 inches apart
Planting Depth
1.0 inch
Min Soil Temp
35°F
Germination
7–14 days
Days to Maturity
90–120 days
Frost Tolerance
Heavy frost tolerance
Soil pH
6.0–7.0
Difficulty
Moderate
Planting Schedule by Zone
Select your USDA zone below for a detailed guide with tips specific to your region.
| Zone | Start Indoors | Transplant | Direct Sow | Harvest Start | Harvest End |
|---|---|---|---|---|---|
| Zone 3 | Apr 17 | May 15 | May 15 | Aug 23 | Sep 12 |
| Zone 4 | Apr 12 | May 10 | May 10 | Aug 18 | Sep 22 |
| Zone 5 | Apr 2 | Apr 30 | Apr 30 | Aug 8 | Oct 2 |
| Zone 6 | Mar 18 | Apr 15 | Apr 15 | Jul 24 | Sep 22 |
| Zone 7 | Mar 8 | Apr 5 | Apr 5 | Jul 14 | Sep 12 |
| Zone 8 | Feb 20 | Mar 20 | Mar 20 | Jun 28 | Aug 27 |
| Zone 9 | Jan 31 | Feb 28 | Feb 28 | Jun 8 | Aug 7 |
| Zone 10 | Jan 13 | Feb 10 | Feb 10 | May 21 | Jul 20 |
| Zone 11 | Jan 1 | Jan 15 | Jan 15 | Apr 25 | Jun 24 |
What you'll need — Your Zone
🛒 Onion — Seeds & Supplies
- 🌱 Onion Seeds
Search for these at your local garden center or nursery.
Companion Planting
Companion planting improves growth, deters pests, and makes better use of garden space.
✓ Good Companions
✗ Avoid Nearby
Beans Peas
📚 Data Sources
Frost dates: NOAA Climate Normals 1991–2020, National Centers for Environmental Information.Hardiness zones: USDA Plant Hardiness Zone Map, Agricultural Research Service.
Growing requirements: Cooperative Extension Services — NC State, Penn State, University of Florida IFAS.
Companion planting: Cornell University Cooperative Extension.
Data compiled from public agricultural sources. Always verify with your local extension office for micro-climate adjustments.