As far as the calendar is concerned, spring is half over, despite the sense for many of us in 2017 that is yet to begin! 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)
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 night time temperatures to be steadily above 10°C (50°F).