Pacific Northwest Seed Germination this June

Pacific Northwest (Zones 7b–9)

The core PNW seed-starting challenge almost every year is heat and light deficiency — not cold. This week breaks that pattern, and it's worth paying attention to.

Coastal Oregon and Washington growers (Zone 8b–9): Portland is under a heat advisory right now, with highs forecast to hit 93°F Monday and 96°F Tuesday. That's a genuine anomaly for this region and a rare gift for seed starting — use it. Sow this week while the heat holds. It won't last: Portland drops back to 77°F by Thursday and continues cooling into the upper 60s and low 70s through the weekend as rain returns. Have your grow lights and heat mats ready to take back over once the marine air comes back in.

Inland Pacific Northwest growers in the Willamette Valley or Puget Sound lowlands (Zone 8a): you're seeing a milder version of the same spike. Take advantage of it the same way, but expect nights to stay cooler than Portland's urban heat island — keep a heat mat as backup rather than relying on ambient warmth alone.

Higher elevation or inland Washington/Idaho border growers (Zone 7b): this particular heat advisory likely won't reach you with the same intensity. Treat it as a reminder rather than a direct instruction — your default protocol of heat mat plus supplemental lighting through most of the season still applies. Desert Oasis Germination Media's moisture retention matters more for this group specifically, since trays under grow lights and heat mats dry out faster than trays warmed by ambient air.

Cheers, Happy Growing!

Michael