When to plant sweet corn in Winthrop and Twisp, WA

Plant sweet corn from seed, directly in the garden in Winthrop and Twisp, May 22 – Jun 26.

Moderate Plant seeds in the ground

Why these dates

Winthrop and Twisp's typical last spring frost is May 15. Frost kills sweet corn, so planting starts once frost risk drops, around May 22. Keep row cover or a frost blanket handy for the first couple of weeks, since a late frost is still possible.

Inland Northwest. Higher, colder interior valleys. Cold springs and an earlier fall mean a shorter season; quick-maturing varieties pay off.

Difficulty: Moderate
Sun: Full sun
Spacing: 10 inches apart in a block of short rows
Planting depth: 1 inch deep
Frost: Killed by frost
First harvest: About 80 days after planting

Step by step

Prepare the bed: loosen the soil and mix in an inch or two of compost.
Plant seeds May 22 – Jun 26, 1 inch deep, 10 inches apart in a block of short rows.
Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
Harvest: Ready about three weeks after the silks appear, when the silks are brown and the kernels squirt milky juice.

Varieties that do well here

Early Sunglow
Bodacious
Golden Bantam

Watch out for

Crows pull up sprouting seeds. Cover the bed with netting or row cover until plants are 4 inches tall.

Plant in blocks of at least four short rows, not one long row, for good pollination.

Common questions

When is the last frost in Winthrop and Twisp, WA?

Typically May 15. In 9 years out of 10, frost is over by June 1. These are 1991–2020 NOAA climate normals for Winthrop.

Is it too late to plant sweet corn in Winthrop and Twisp?

The spring planting window runs through June 26. Later plantings may not have time to produce before the first fall frost, which usually arrives around September 22.

How long until I can harvest sweet corn?

About 80 days after planting. Ready about three weeks after the silks appear, when the silks are brown and the kernels squirt milky juice.

Also plant in Winthrop and Twisp around the same time

Planting dates for sweet corn in nearby areas

Wenatchee, WA Apr 25 – May 30
Omak and Okanogan, WA May 15 – Jun 19
Chelan, WA Apr 25 – May 30
Leavenworth, WA May 17 – Jun 21
Ellensburg, WA May 15 – Jun 19
Spokane, WA May 15 – Jun 19

Full planting calendar for Winthrop and Twisp · Sweet corn in every city