When to Plant Onion in Cambridge, Maryland (21613)
Location
Cambridge, Maryland
ZIP Code
21613
USDA Zone
8a
Last Frost
Friday, March 20, 2026
📅 Planting Calendar
Start Seeds Indoors Friday, January 23, 2026
Transplant Outdoors Friday, April 3, 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
Mature Height 12-18"
Spread 4"
Type Bulb
Fruit Size Medium (2-4 inch bulb)
☀️ Growing Requirements
☀️
Sun
Full Sun (6+ hours)
💧
Water
Moderate
↔️
Spacing
4" apart
🌱
Planting Depth
0.5" deep
Seeds typically germinate in 7-10 days
🤝 Good Companions
CarrotBeetLettuceTomatoBrassicas
⚠️ Avoid Planting Near
BeanPeaAsparagus
Other Plants for Cambridge
Blackberry Blueberry Raspberry Strawberry Basil Chamomile Chives Cilantro Dill Lavender Lemon Balm Marjoram Mint Oregano Parsley Rosemary Sage Tarragon Thyme Acorn Squash Artichoke Arugula Asparagus Beefsteak Tomato Beet Bell Pepper Bok Choy Broccoli Brussel Sprout Butternut Squash Cabbage Cantaloupe Carrot Cauliflower Cayenne Pepper Celery Cherry Tomato Chili Pepper Collard Green Common Bean Cucumber Eggplant Endive Fennel Garlic Grape Tomato Green Bean Habanero Pepper Head Lettuce Heirloom Tomato Honeydew Melon Jalapeño Pepper Kale Kohlrabi Leaf Lettuce Leek Lima Bean Mustard Okra Parsnip Pea Poblano Pepper Pole Pea Potato Pumpkin Radicchio Radish Rhubarb Roma Tomato Rutabaga Serrano Pepper Shallot Snap Pea Snow Pea Spaghetti Squash Spinach Squash Sweet Corn Sweet Potato Swiss Chard Tomato Turnip Watermelon Zucchini
Growing Onion in Zone 8a
Onion (Allium cepa) is a popular garden vegetable. In Cambridge, Maryland, which is in USDA Hardiness Zone 8a, you should start seeds indoors around Friday, January 23, 2026.
Your average last frost date is Friday, March 20, 2026. Plan to transplant your Onion seedlings outdoors around Friday, April 3, 2026, about 2 weeks after your last frost date.