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Sow winter's dinner in June heat — broccoli seedlings while the tomatoes flex.

Starting fall brassicas indoors in Portland in early June feels counterintuitive when the thermometer is flirting with 87°F, but this is exactly when the long game begins. Broccoli, cabbage, and kale need eight to ten weeks of growth before going out in August, which puts sowing day squarely on the calendar this week. Get the trays going now and you will be eating sweet, frost kissed brassicas well into December.

This Week's Action List

  • Sow broccoli (try Belstar or Green Magic), cabbage (Caraflex, Famosa), and kale (Lacinato, Winterbor) into 72 cell trays this week using a sterile seed starting mix. Keep soil at 65 to 75°F for fast germination — most seeds will pop in three to five days.
  • With Tuesday hitting 87°F, place trays in the coolest spot you have — a north facing window, basement under lights, or a shaded porch. Brassica seedlings bolt or stretch badly in heat above 80°F, so a cool start matters more than full sun right now.
  • Side dress your established tomatoes, corn, and squash this week with a nitrogen source like blood meal (one tablespoon per plant) or fish emulsion diluted to label rate. With dry weather Monday through Thursday, water it in deeply to move nutrients to the root zone.
  • Sow a second succession of bush beans (Provider, Jade) directly into warm soil this week — soil temps should be a comfortable 65°F after the weekend's mild spell. Stagger plantings every two to three weeks through mid July for beans into October.
  • Harvest lettuce aggressively before Tuesday's 87°F spike triggers bolting. Cut whole heads in the cool of morning, refrigerate immediately, and replace those beds with heat tolerant successions like Jericho romaine or skip to fall brassica space.

Frequently Asked Questions

When should I start fall broccoli and cabbage seeds in Portland?

Early to mid June is the sweet spot for Portland Zone 8b. Brassicas need eight to ten weeks indoors before transplanting in mid August, which sets them up to mature in the cool September and October weather they prefer.

Can I direct sow fall brassicas instead of starting indoors?

You can, but Portland's June soil is often too warm for reliable brassica germination and slugs decimate young direct sown seedlings. Starting in trays under your control gives much higher success rates and lets you protect tender seedlings until they are tough enough to transplant.