Seeds to Start in May

Spring is half over, but there are still dozens of seeds to start in May. It can still be cold at night, so some seeds will continue to benefit from starting indoors in a warm room. Most seeds will germinate faster and more evenly if heated from below with a heating mat. Other seeds actually prefer cool soil for germination, and they can be direct sown in May here on the coast.

Start these seeds indoors in May:

Asparagus (start indoors in the first week for transplanting mid-June)
Brussels Sprouts (sow indoors last week in May for early August transplanting)
Cauliflower (start indoors for transplanting June to August)
Cucumbers (start them indoors in the second week in May, transplant in June)
Pumpkins & Squash (start indoors before the 15th for transplanting in June)

Seeds to Start in May

Direct sow outdoors in May:

Alyssum (after the 15th)
Amaranth (after the 15th)
Arugula (continue direct sowing short rows)
Asclepias
Basil (after the 15th)
Soybeans (last week of May, if warm enough)
Bush Beans & Pole Beans (after the 15th)
Beets
Borage
Broccoli
Cabbage
Calendula
Carrots
Catnip
Celery
Celosia
Chamomile
Cilantro
Clarkia
Cleome
Cosmos
Cynoglossum
Dill
Echinacea (after the 15th)
Fennel
Gaillardia
Gaura (before the 15th)
Gypsophila
Iberis
Kale
Kohlrabi
Leeks
Lemon Balm
Lettuce
Mint
Morning Glory
Nasturtiums
Nemophila
Nicotiana
Nigella
Oregano (after the 15th)
Pac Choi
Parsley (May is the best time to direct sow parsley seeds)
Parsnips
Peas (up to the end of May)
Phacelia
Quinoa
Radishes (until the 7th)
Scallions
Spinach
Stocks
Sunflowers
Sweet Peas (to the end of the month)
Swiss Chard
Tithonia
Turnips
Verbena
Veronica
Wildflowers (to the end of the month)
Zinnia

It’s still too cold at night to transplant tomatoes and tender perennials outdoors without protection. Wait for nighttime temperatures to be steadily above 10°C (50°F). If you live outside of our mild coastal growing area, please look to our Planting Charts adjusted to your region.

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