One of the best tools that you have as a gardener to help figure out your gardening schedule is the USDA zone info. The zone information's most crucial data reveals the average last frost and the lowest expected temperature for your area.
To determine the appropriate planting time for onions, you can utilize the USDA zone information for the 9a region.
Planting Calendar for Onions
| Frost tolerance for onions | Very tolerant of frost |
| When to plant | Up to 7 weeks before last frost |
Because onions are can tolerate cold temperatures, you can plant them earlier in the year compared to other frost-sensitive plants.
Visual Calendar for Onions
Planting Calendar for Onions in Zone 9a
Key dates to remember:
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Start seeds indoors: | Jan 1 |
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Direct sow seeds: | Jan 1 |
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Transplant starts outside: | Jan 15 |
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Summer harvest time: | Feb 15 |
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Start winter crop: | Sep 15 |
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Start over-winter: | Dec 1 |
Last Frost Date for Zone 9a
The average date of last frost is February 15 in zone 9a. It might get as low as 20°F (-6°C) during the coldest months of winter.
As the USDA zone information for zone 9a is only an average, the actual date of your last frost will differ annually. Since every microclimate is different, you should also watch the weather forecast closely as you get close to planting time. Watch the weather forecast before planting outside, and have frost protection ready if low temperatures are expected.
USDA Info for Zone 9a
Here is the info for USDA zone 9a.
| Average Date of Last Frost (spring) | February 15 |
| Average Date of First Frost (fall) | 2015-12-15 |
| Lowest Expected Low | 20°F (-6°C) |
| Highest Expected Low | 25°F (-3°C) |
This means that on a really cold year, the coldest it will get is 20°F (-6°C). On most years you should be prepared to experience lows near 25°F (-3°C).
Other Plants to Grow in Zone 9a
You may be interested in our other planting guides for zone 9a.
Vegetables in Zone 9a
- Amaranth
- Artichokes
- Arugula
- Asparagus
- Beans
- Beets
- Bok Choy
- Broccoli
- Brussels Sprouts
- Cabbage
- Cantaloupe
- Carrots
- Cauliflower
- Celery
- Chervil
- Collard Greens
- Corn
- Cornsalad
- Cucumbers
- Eggplant
- Garlic
- Ginger
- Green Onions
- Honeydew Melons
- Kale
- Kohlrabi
- Leeks
- Lettuce
- Melons
- Okra
- Onions
- Parsnips
- Peas
- Peppers
- Potatoes
- Pumpkins
- Radicchio
- Radishes
- Rhubarb
- Rutabaga
- Shallots
- Spinach
- Strawberries
- Summer Squash
- Sweet Potatoes
- Swiss Chard
- Tomatilloes
- Tomatoes
- Turnips
- Watercress
- Watermelon
- Winter Squash
- Zucchini
Herbs in Zone 9a
Flowers in Zone 9a
- Alyssum
- Amaranth
- Anemones
- Asters
- Bachelors Buttons
- Begonias
- Bells of Ireland
- Black-eyed Susans
- Bleeding Hearts
- Calendula
- Carnations
- Chinese Lanterns
- Chrysanthemums
- Clematis
- Coleus
- Columbine
- Coneflowers
- Coreopsis
- Cornflowers
- Cosmos
- Crocus
- Daffodils
- Dahlia
- Daisies
- Daylilies
- Delphiniums
- Dianthus
- Dusty Miller
- Echinacea
- Foxgloves
- Geraniums
- Hellebores
- Heuchera
- Hibiscus
- Hollyhocks
- Hostas
- Hydrangeas
- Impatiens
- Iris
- Lantana
- Lilies
- Lobelia
- Love-in-a-mist
- Lupine
- Marigolds
- Morning Glories
- Nasturtiums
- Pansies
- Peonies
- Petunias
- Phlox
- Poppies
- Portulaca
- Primrose
- Red Hot Pokers
- Roses
- Rudbeckia
- Salvia
- Shasta Daisies
- Snapdragons
- Statice
- Stocks
- Strawflowers
- Sunflowers
- Sweet Peas
- Tulips
- Verbena
- Vinca
- Violets
- Wisteria
- Yarrow
- Zinnias
USDA Zones
USDA zones are a popular way of determining which plants can grow in your area. Zones tell you when your average first and last frost date are, as well as how cold you can expect it to get in the winter.
Our site works best if you choose your zone from the list below. If you do not know your USDA zone, then you can use our zone map.
