When to Plant Onions in Maryland
The backbone of the kitchen garden. Choose short-day, intermediate, or long-day varieties based on your latitude.
The Short Answer
Maryland Frost Dates
Your planting dates depend on which part of Maryland you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Western Maryland | 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| Central Maryland | 6b, 7a | Apr 10 - Apr 25 | Oct 10 - Oct 25 |
| Eastern Shore | 7a, 7b, 8a | Apr 1 - Apr 15 | Oct 20 - Nov 5 |
Onions Planting Schedule for Maryland
Western Maryland (Zones 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Central Maryland (Zones 6b, 7a)
Average last frost: Apr 10 - Apr 25 · Average first frost: Oct 10 - Oct 25
Eastern Shore (Zones 7a, 7b, 8a)
Average last frost: Apr 1 - Apr 15 · Average first frost: Oct 20 - Nov 5
Growing Onions in Maryland
Onions in Maryland's Climate
Long-day onions are your type. Plant sets or transplants as soon as ground can be worked in spring. For the largest bulbs, start from seed indoors 10-12 weeks before last frost. Your June day length (15+ hours) triggers proper bulbing. Cure in a warm, dry location for 2-3 weeks before storage.
Soil Considerations for Maryland
Clay soils in Piedmont. Sandy loam on Eastern Shore. Acidic in most areas. Rich alluvial soils along river valleys. Loose, well-drained soil is especially important for onions since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
Maryland Climate & Growing Season
Moderate climate with four seasons. Hot, humid summers. Good growing season. Diverse growing conditions across the state. Onions can handle frost well, which is an advantage in Maryland's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Maryland: Western Maryland (5b, 6a) has a last frost around May 1 - May 15, while Eastern Shore (7a, 7b, 8a) sees frost end around Apr 1 - Apr 15. This difference matters for onions — but onions handle frost well, so the timing difference is less critical.
Growing Tips
Day length triggers bulbing. Northern gardeners need long-day varieties. Southern gardeners need short-day varieties.
Companion Planting
Plant onions alongside these companions for better growth:
Keep onions away from:
The Bottom Line
Last reviewed: March 29, 2026