Rainline Garden
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A zucchini plant with yellow flowers and a young squash

When to plant · 5 plants

Squash, cucumbers and melons

Sprawling vines for the warmest part of summer. Pick one for its dates in your town and how to grow it.

Planting order

When each one first goes in around Portland, starting indoors where that comes first. Colder towns run later.

Late spring
Cucumbers, Zucchini and summer squash, Winter squash, Pumpkins, Melons

Planting windows at a glance

Main planting window in five reference towns. Each plant's page has every town.

PlantPortlandSeattle and TacomaBend and RedmondSpokaneBoise and Meridian
CucumbersMay 15 – Jun 12May 15 – Jun 12Jun 9 – Jul 7May 20 – Jun 17May 1–29
Zucchini and summer squashMay 15 – Jun 12May 15 – Jun 12Jun 9 – Jul 7May 20 – Jun 17May 1–29
Winter squashMay 15 – Jun 5May 15 – Jun 5Jun 9–30May 20 – Jun 10May 1–22
PumpkinsMay 15 – Jun 5May 15 – Jun 5Jun 9–30May 20 – Jun 10May 1–22
MelonsMay 25 – Jun 15May 25 – Jun 15Jun 16 – Jul 7May 30 – Jun 20May 10–31

Growing squash, cucumbers and melons in the Northwest

Squash, cucumbers, pumpkins and melons are fast-growing vines that need warm soil, full sun and room to sprawl. Seeds rot in cold, wet ground, so wait until the soil has warmed, or start them indoors a few weeks ahead and transplant carefully; they don't like their roots disturbed.

Zucchini and cucumbers are quick and productive almost anywhere in the region. Winter squash, pumpkins and especially melons need a long, warm season, and in cool western and coastal gardens they're a stretch without help: choose short-season varieties, use black plastic or a row cover early on, and pinch off new flowers in late summer so the vine ripens the fruit it already has.

Powdery mildew, the white coating on older leaves in late summer, is almost universal and usually arrives late enough not to matter much. Water at the base rather than over the leaves. Zucchini is the easiest place to start; two plants are plenty for most households.

Common questions

When should I plant squash and cucumbers?

After the soil warms, usually late May to early June on the west side. They sulk in cold soil, and slugs eat young seedlings, so it pays to wait.

Can I grow melons west of the Cascades?

Yes, with help. Choose small, early varieties, plant in the warmest spot, and use black plastic mulch or a cloche early on. Eastern valleys grow melons easily.

Why are my squash flowers falling off without fruit?

The first flowers are often male, which drop naturally. If female flowers (with a tiny fruit at the base) also drop, cool weather or few bees are limiting pollination.

Other plant types

Plants for your conditions