One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.
You should be able to figure out when it's the best time to plant onions by reviewing the USDA zone info for Washington.
Planting Calendar for Onions
Frost tolerance for onions: | Very tolerant of frost. |
When to plant: | Up to 7 weeks before last frost. |
You can plant onions earlier in the year because they are very cold tolerant.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
---|---|---|---|---|---|---|---|---|---|---|---|
Legend | |
---|---|
A good time to plant onions | |
Possibly ok, but a risky time to plant onions | |
Probably not a good time to plant onions |
The earliest that you can plant onions in Washington is February. However, you really should wait until March if you don't want to take any chances.
The last month that you can plant onions and expect a good harvest is probably September. If you wait any later than that and your onions may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your onions indoors.
Last Frost Date
The average date of last frost is April 15 in Washington. In the coldest months of winter you can expect an average low temperature of -15°F.
Since the USDA zone info for Washington is an average the actual date of last frost will vary from year to year. Half of the time in Washington you get a frost after April 15 so make sure that you are ready to cover your onions in the event of a late frost.
USDA Zone Info for Washington
Here is the info for USDA Zone 5b.
Average Date of Last Frost (spring) | April 15 |
Average Date of First Frost (fall) | October 15 |
Lowest Expected Low | -15°F |
Highest Expected Low | -10°F |
This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.
Plants to Grow in Washington
You may be interested in your other planting guides for Washington.
Vegetables
- Artichokes
- Asparagus
- Asparagus lettuce
- Asparagus peas
- Beets
- Bell Peppers
- Bittercress
- Black pepper
- Black radish
- Bok Choi
- Broccoli
- Brussels Sprouts
- Bunching Onions
- Cabbage
- Cantaloupes
- Carrots
- Cauliflower
- Celeriac
- Celery
- Chard
- Chicory
- Chinese cabbage
- Chives
- Corn
- Corn salad
- Cucumbers
- Eggplants
- Endive
- Fennel
- Field Peas
- Garden cress
- Garlic
- Gherkins
- Green beans
- Hamburg root parsley
- Iceberg lettuce
- Indian cress
- Jerusalem artichokes
- Kale
- Kohlrabi
- Leeks
- Lettuce
- Melons
- Mustard greens
- Napa cabbage
- Neeps
- New Zealand spinach
- Okra
- Onions
- Parsnip
- Pea
- Peanut
- Pearl onions
- Peas
- Pole beans
- Potatos
- Pumpkins
- Purslane
- Radicchio
- Radishes
- Red cabbage
- Rhubarb
- Romaine lettuce
- Romanesco
- Runner beans
- Salsify
- Savoy cabbage
- Scallions
- Shallots
- Snap beans
- Snow peas
- Spinach
- Squash
- Strawberries
- String beans
- Sweet corn
- Sweet Potatos
- Tomatos
- Tree onions
- Turnips
- Watercress
- Watermelon
- Welsh onion
- Zucchini
Herbs
Flowers
- Abutilon
- Achillea
- Achimenes
- Aegopodium
- African Daisy
- Ageratum
- Ajuga
- Alstromeria
- Alternanthera
- Alternaria
- Alyssum
- Amaranthus
- Anagallis
- Anchusa
- Anemone
- Angelonia
- Angel's Trumpets
- Arabis
- Arctotis
- Argyranthemum
- Armeria
- Artemesia
- Asparagus Fern
- Asters
- Astilbe
- Aubretia
- Aubrieta
- Aurinia
- Axilflower
- Baby Blue Eyes
- Baby's Breath
- Bachelor Buttons
- Bacopa
- Balloon Flower
- Balsam
- Banana
- Basket of Gold
- Bee Balm
- Begonias
- Bellis
- Bells of Ireland
- Bidens
- Bishop's Weed
- Black Eyed Susans
- Bleeding Hearts
- Bloodleaf
- Blue Lace Flowers
- Blue Throatwort
- Bougainvillea
- Bower Vine
- Brachycome
- Browallia
- Brunfelsia
- Buddha belly plant
- Bunny Tails grass
- Caladium
- Calendula
- Calibrachoa
- California Poppy
- Calla Lily
- Calliopsis
- Campanula
- Candytuft
- Canna
- Cardinal Flower
- Carnation
- Catharanthus
- Celosia
- Centaurea
- Cerastium
- Chocolate Daisy
- Chrysanthemum
- Chrysanthemums
- Chrysocephalum
- Cigar Plant
- Cleome
- Clover
- Coleus
- Columbine
- Common hollyhock
- Copperleaf
- Coral Bells
- Coreopsis
- Cosmos
- Crassula
- Creeping Phlox
- Creeping Zinnia
- Crossandra
- Cuphea
- Dahlberg Daisy
- Dahlia
- Dahlias
- Dallas Fern
- Datura
- Daylily
- Decorative Kale
- Delphinium
- Dianthus
- Diascia
- Dichondra
- Didiscus
- Digitalis
- Dipladenia
- Doronicum
- Dracaena
- Dusty Miller
- Echinacea
- Elephant Ears
- English Daisy
- Erysimum
- Euphorbia
- Evolvulus
- Fanflower
- Felicia Daisy
- Festuca
- Feverfew
- Fiber Optic Grass
- Firebush
- Flax
- Flowering Kale
- Flowering Maple
- Flowering Tobacco
- Flower-of-an-Hour
- Forget-Me-Not
- Fountain Grass
- Four O' Clock
- Four-o-clock flower
- Foxglove
- Fuchsia
- Gaillardia
- Galium
- Garden Mums
- Gayfeather
- Gazania
- Geranium
- Gerbera
- Geum
- Gladiolus
- Gloriosa Daisy
- Gloriosa Lily
- Gomphrena
- Guara
- Gypsophila
- Hamelia
- Hardy Asters
- Hardy Hibiscus
- Helianthemum
- Heliotrope
- Hemerocallis
- Heuchera
- Hibiscus
- Hollyhocks
- Hosta
- Hypericum
- Iberis
- Iceland Poppy
- Impatiens
- Iresene
- Jasmine
- Lantana
- Larkspur
- Lavender
- Lavender Cotton
- Lenten Rose
- Liatris
- Lisianthus
- Lithospermum
- Livingstone Daisy
- Lobelia
- Lotus Vine
- Lunaria
- Lupine
- Lysimachia
- Maltese Cross
- Marguerite Daisy
- Marigold
- Matricaria
- Mecardonia
- Melampodium
- Mexican Feather Grass
- Millet
- Mimulus
- Missouri Primrose
- Monarda
- Money Plant
- Monkey Flower
- Moon Vine
- Morning Glory
- Myosotis
- Napa Valley Fern
- Nasturtium
- Nemesia
- Nicotiana
- Nierembergia
- Nigella
- Nolana
- Oenothera
- Oleander
- Oriental poppies
- Ornamental Grasses
- Osteospermum
- Oxalis
- Painted Daisies
- Painted Tongues
- Pampas Grass
- Pansies
- Pennisetum
- Penstemon
- Pentas
- Peonies
- Perilla
- Periwinkles
- Petunias
- Phlox
- Pincushion Flower
- Platycodon
- Plectranthus
- Polka Dot Plant
- Polygonums
- Poppies
- Portulaca
- Primroses
- Primula
- Purple Bell Vines
- Purple Coneflower
- Purple Rock Cress
- Pyrethrum
- Red Hot Pokers
- Regal Geranium
- Rock Cress
- Roses
- Ruby Grass
- Rudbeckia
- Sagina
- Salpiglossis
- Salvia
- Santolina
- Sanvitalia
- Saxifraga
- Scabiosa
- Scaevola
- Scarlet Pimpernels
- Scarlet Runner Beans
- Schizanthus
- Scutellaria
- Sedum
- Shasta Daisys
- Skullcap
- Snapdragons
- Snow-in Summer
- Statice
- Steirodiscus
- Stocks
- Stoneseed
- Strawflowers
- Streptocarpella
- Sunflowers
- Sutera
- Swan River Daisy
- Sweet Peas
- Sweet Potato Vine
- Sweet Sultan
- Sweet Williams
- Sweet Woodruff
- Tagetes
- Tall Phlox
- Thunbergia
- Tithonia
- Torch Lilys
- Torenia
- Trachelium
- Trailing Portulaca
- Transvaal Daisy
- Trifolium
- Tritoma
- Tropical Hibiscus
- Tropical Water Plants
- Twinspur
- Verbena
- Veronica
- Vinca Vine
- Violas
- Violets
- Xerianthemum
- Yarrow
- Zinnia