Rainline Garden

When to plant sweet corn in Tri-Cities (Pasco, Kennewick, Richland), WA

Plant sweet corn from seed, directly in the garden in Tri-Cities (Pasco, Kennewick, Richland), May 4 – Jun 8.

Moderate Plant seeds in the ground

Why these dates

Tri-Cities (Pasco, Kennewick, Richland)'s typical last spring frost is April 27. Frost kills sweet corn, so planting starts once frost risk drops, around May 4. Keep row cover or a frost blanket handy for the first couple of weeks, since a late frost is still possible.

Columbia Basin and low eastern valleys. Hot, dry summers and quick spring warm-up. Warm crops go in earlier than west of the Cascades, and irrigation matters more than rain.

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

  1. Prepare the bed: loosen the soil and mix in an inch or two of compost.
  2. Plant seeds May 4 – Jun 8, 1 inch deep, 10 inches apart in a block of short rows.
  3. Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
  4. 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 Tri-Cities (Pasco, Kennewick, Richland), WA?

Typically April 27. In 9 years out of 10, frost is over by May 10. These are 1991–2020 NOAA climate normals for Pasco Tri-Cities Airport.

Is it too late to plant sweet corn in Tri-Cities (Pasco, Kennewick, Richland)?

The spring planting window runs through June 8. Later plantings may not have time to produce before the first fall frost, which usually arrives around October 11.

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 Tri-Cities (Pasco, Kennewick, Richland) around the same time

Planting dates for sweet corn in nearby areas

Full planting calendar for Tri-Cities (Pasco, Kennewick, Richland) · Sweet corn in every city