When to plant tomatoes in Omak and Okanogan, WA

Start tomatoes from seed indoors Mar 25 – Apr 8, then plant the young plants in the garden in Omak and Okanogan May 20 – Jun 17.

Moderate Plant young plants (starts)

Why these dates

Omak and Okanogan's typical last spring frost is April 30. Frost kills tomatoes, and warm-season crops also need warm soil. Soil here stays cold for weeks after the last frost, so planting waits until about May 20.

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; the hottest spot you have
Spacing: 2 feet apart
Planting depth: Bury the stem up to the first leaves
Frost: Killed by frost
First harvest: About 75 days after planting

Step by step

Start seeds indoors Mar 25 – Apr 8 in trays or small pots under a grow light or in your sunniest window. Or skip this step and buy young plants (starts) at a garden center.
Harden off the young plants: about a week before planting, set them outside for a few hours a day, a little longer each day.
Plant them in the garden May 20 – Jun 17, 2 feet apart. Bury the stem up to the first leaves.
Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
Harvest: Pick when fully colored. Before fall rains, pick green tomatoes and ripen them indoors.

Varieties that do well here

Stupice
Early Girl
Sungold (cherry)
Oregon Spring (bred in Oregon)

Watch out for

Late blight in wet falls turns leaves and fruit brown. Keep leaves dry and give plants space.

Wait for warm soil and mild nights before planting out. Early or cherry varieties ripen most reliably here.

Common questions

When is the last frost in Omak and Okanogan, WA?

Typically April 30. In 9 years out of 10, frost is over by May 15. These are 1991–2020 NOAA climate normals for Omak Airport.

Is it too late to plant tomatoes in Omak and Okanogan?

The spring planting window runs through June 17. Later plantings may not have time to produce before the first fall frost, which usually arrives around October 7.

When should I start tomatoes from seed indoors in Omak and Okanogan?

March 25 to April 8, which is 8 to 6 weeks before the May 20 planting date. Or buy young plants at a garden center instead.

What Your Last Frost Date Really MeansA last frost date isn't a promise. Here's what the number on a planting chart actually measures, and how to use it without losing your tomatoes.
How to Harden Off Seedlings Before Planting OutSeedlings raised indoors need a week or two to adjust to sun, wind and cool nights. Here's a simple day-by-day schedule that works in a Northwest spring.
Late Blight on Tomatoes: How to Spot It and Keep It AwayCool, wet weather makes late blight a real threat to Northwest tomatoes and potatoes. Learn the signs, how it differs from other leaf spots, and how to prevent it.
Starting Vegetable Seeds Indoors: A Northwest TimelineWhen to start tomatoes, peppers and other seeds indoors in Oregon and Washington, plus the simple setup that grows strong seedlings.
How Much to Water Vegetables in a Dry Northwest SummerThe Northwest is rainy for nine months and bone dry for three. How much water vegetables need in summer, when to water, and how to waste less of it.
Raised Beds for Rainy Northwest GardensWhy raised beds suit the Northwest so well, how big and deep to build them, what to fill them with, and the mistakes to avoid.
Growing Vegetables in Containers on a Northwest Balcony or PatioNo yard? Herbs, greens, tomatoes and more grow well in pots. Container sizes, soil, watering and the best crops for small Northwest spaces.
The Best Tomatoes for Cool Northwest SummersWhich tomato varieties actually ripen in Portland, Seattle and the coast, and how to give them the heat they need.
Gardening in Bend and Central Oregon's Short SeasonHow to grow vegetables where frost can come almost any month: what to plant, when, and how to protect it.
Why Northwest Gardeners Should Plant by Soil TemperatureThe air warms up long before the soil does here. A $10 soil thermometer tells you when it's really time to plant beans, squash and tomatoes.

Also plant in Omak and Okanogan around the same time

Planting dates for tomatoes in nearby areas

Ellensburg, WA May 20 – Jun 17
Spokane, WA May 20 – Jun 17

Full planting calendar for Omak and Okanogan · Tomatoes in every city