Rainline Garden

When to plant sunflowers in The Dalles, OR

Plant sunflowers from seed, directly in the garden in The Dalles, Apr 25 – Jun 6.

Easy Plant seeds in the ground

Why these dates

The Dalles's typical last spring frost is April 11. Frost kills sunflowers, and warm-season crops also need warm soil. Soil here stays cold for weeks after the last frost, so planting waits until about April 25. 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
Easy
Sun
Full sun
Spacing
6 inches (small types) to 24 inches (giants) apart
Planting depth
1 inch deep
Frost
Killed by frost
Flowers
Blooms about 60 to 90 days after sowing

Step by step

  1. Prepare the bed: loosen the soil and mix in an inch or two of compost.
  2. Plant seeds Apr 25 – Jun 6, 1 inch deep, 6 inches (small types) to 24 inches (giants) apart.
  3. Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
  4. Harvest: Cut flowers when the petals are just opening. For seeds, let heads dry on the plant until the back turns brown, and cover them from birds.

Varieties that do well here

  • Mammoth Grey Stripe (giant)
  • ProCut (for cutting)
  • Teddy Bear (dwarf)

Watch out for

Birds and slugs eat seedlings. Cover the seedbed until plants are a few inches tall.

Sow them where they'll grow; they dislike transplanting. Tall varieties need a spot out of the wind.

Common questions

When is the last frost in The Dalles, OR?

Typically April 11. In 9 years out of 10, frost is over by April 28. These are 1991–2020 NOAA climate normals for The Dalles Municipal Airport (Dallesport, WA).

Is it too late to plant sunflowers in The Dalles?

The spring planting window runs through June 6. Later plantings may not have time to bloom well before the first fall frost, which usually arrives around October 26.

When do sunflowers bloom?

Blooms about 60 to 90 days after sowing. Cut flowers when the petals are just opening. For seeds, let heads dry on the plant until the back turns brown, and cover them from birds.

Also plant in The Dalles around the same time

Planting dates for sunflowers in nearby areas

Full planting calendar for The Dalles · Sunflowers in every city