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Seeds in soil, eyes on the thermometer, fingers crossed against the slugs.

Late May is the sweet spot to direct sow beans and squash in Portland, with soil finally holding steady above 60°F across most of the metro. Eastside gardens are already there; if you garden in the West Hills or out toward Forest Park, give it another few days. This week is the moment to get those seeds in the ground before June heat dries the top inch too fast for reliable germination.

This Week's Action List

  • Check soil temperature at 8am, four inches deep, before sowing. Beans germinate reliably at 60°F; squash and cucumbers prefer 65 to 70°F. A $10 soil thermometer from Portland Nursery pays for itself the first season.
  • Sow bush beans like 'Provider' or 'Jade' one inch deep, three inches apart, in rows 18 inches apart. For pole beans, 'Fortex' and 'Rattlesnake' both crush it in Portland's long, warm August.
  • Plant summer squash ('Costata Romanesco', 'Dunja') and winter squash ('Delicata', 'Honeynut') in mounds, two to three seeds per hill, hills spaced four to six feet apart. Thin to the strongest seedling once true leaves appear.
  • Pre soak bean seeds for two to four hours (not overnight, or they crack), but never pre soak squash or cucumber seeds — they rot. Sow directly into moist, but not soggy, soil.
  • Set out copper tape or fresh Sluggo around every newly sown hill. Portland slugs find squash and bean cotyledons within 48 hours, and one bad night can erase the whole planting.

Frequently Asked Questions

Is it too late to direct sow beans in Portland in late May?

Not at all — late May is actually ideal. Bush beans planted now will start producing by mid July, and you can succession sow another round in late June for a September harvest. Pole beans planted this week will climb through August and crop until first frost in November.

Can I still start squash from seed outdoors in Portland this week?

Yes, direct sowing squash from May 18 through mid June works perfectly in Zone 8b. Soil is warm, frost risk is gone, and the plants will hit peak production in August. Avoid transplanting squash if you can — they sulk after root disturbance and direct sown plants usually catch up within two weeks.