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A pile of fresh green cucumbers

Oregon · Washington · Idaho

When to plant cucumbers

Plant in the garden: Portland and Seattle May 15 – Jun 12; Spokane May 20 – Jun 17; Boise May 1–29; Bend Jun 9 – Jul 7.

Cucumbers are vining squash-family plants grown for crisp fruit eaten raw in salads or brined into pickles. Slicing cucumbers are long and smooth, pickling types are short and bumpy, and thin-skinned English and Middle Eastern types need no peeling. Bitter cucumbers come from stress: heat or dry soil builds up bitter compounds in the fruit.

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Puts cucumbers on your free plan, with dates for your town and a spot in your beds.

Difficulty
Moderate
Sun
Full sun
Spacing
12 inches apart on a trellis
Planting depth
1 inch deep
Frost
Killed by frost
First harvest
About 60 days after planting

Need warm soil and warm nights. Floating row cover helps in cool springs.

Cucumber planting dates

TownsStart seeds indoorsPlant in the garden
Portland, OR, Seattle and Tacoma, WAApr 17–24May 15 – Jun 12
Spokane, WA, Astoria, ORApr 22–29May 20 – Jun 17
Boise and Meridian, IDApr 3–10May 1–29
Bend and Redmond, ORMay 12–19Jun 9 – Jul 7

Dates for six main cities. For any of the other 80 towns, type it in the box at the top of the page or browse all towns.

Cucumber year at a glance

TaskJFMAMJJASOND
Start indoorsApr
PlantMayJun
HarvestJulAugSep

Around Portland. Colder towns, especially east of the Cascades, run a few weeks later; the table above has your town's planting dates.

How to grow cucumbers

  1. Start seeds indoors on your city's dates 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.
  2. Harden off the young plants: about a week before planting, set them outside for a few hours a day, a little longer each day.
  3. Plant them in the garden on your city's dates, 12 inches apart on a trellis. If you plant seeds instead, sow them 1 inch deep.
  4. Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
  5. Harvest: Pick slicers at 6 to 8 inches, before they yellow. Check plants every day or two in midsummer.

Growing cucumbers in your part of the Northwest

The same plant behaves differently on the wet west side, the foggy coast and the dry, colder east side.

West-side valleys

Willamette Valley, Puget Sound, southern Oregon

Cucumbers sulk in cold soil, so plant them out in late May or early June. Powdery mildew often shows up in August; resistant varieties help.

Coast

Oregon and Washington coast

Cool summers make cucumbers slow. Grow them in a greenhouse, cold frame or sunny, sheltered spot, or choose quick, cool-tolerant varieties.

East of the Cascades

Columbia Basin, Yakima, Boise, Spokane, north Idaho

Heat suits cucumbers, but they need deep, steady water or the fruit turns bitter and misshapen. Spider mites can build up in hot, dry weather.

High desert and mountain towns

Central Oregon, high eastern Oregon valleys, McCall, Salmon

Cool nights slow cucumbers down. Start them indoors or under cover, and plant after frost danger passes.

More cucumber varieties

More widely sold picks that do well somewhere in the Northwest. The tag says which part of the Northwest suits each one best.

Marketmore 76

Slicer, dark green · 68 days

Straight, dark green slicers about 8 inches long. It resists several cucumber diseases, including powdery mildew and scab, and keeps producing over a long season.

Both sides

Lemon

Round yellow heirloom · 65 days

Round, pale yellow fruits the size of a lemon with mild, sweet flesh. Pick them while still light yellow for the best texture.

Both sides

Diva

Seedless slicer, thin-skinned · 58 days

Smooth, thin-skinned cucumbers that are seedless and never bitter. Plants set fruit without pollination, which helps in cool, cloudy spells when bees are scarce.

Coast and west side

Straight Eight

Slicer heirloom · 58 days

A classic open-pollinated slicer with straight, uniform fruit about 8 inches long. Early, productive and easy to save seed from.

Both sides

Boston Pickling

Pickling heirloom · 55 days

Short, blocky, bumpy fruits that are ideal for pickles. Vines produce heavily over a few weeks, which suits canning batches.

Both sides

Suyo Long

Asian long slicer · 61 days

Long, ribbed, sweet and mild fruits that grow straight when trellised. It tolerates heat and some disease and is rarely bitter.

Both sides

How much to grow

How many to plant

For a family of four, 2 to 4 plants for salads. Plant 6 to 8 if you want to make pickles.

What to expect

About 10 to 20 cucumbers per plant over the season.

Storing the harvest

Keep about a week in the fridge's warmest part; below about 50°F they go soft and pitted.

What to plant after cucumbers

Around Portland, the cucumber harvest wraps up around September. These crops can still go into the same bed, and they come from a different plant family, which helps with rotation.

Portland dates. Pick your town at the top of the page for yours.

Key numbers

Top care tip: Water at the base, not over the leaves, and pick often, because one overgrown cucumber slows the whole vine.

The plant science

The plant biology behind the advice above, in plain language.

Warmth is everything

Cucumbers are a tropical crop. Seeds need soil of at least 60°F to sprout and do best much warmer, and long spells below about 50°F damage plants. In much of the Northwest, transplants or seeds go out only once nights are reliably warm. Black plastic mulch, a south-facing spot and row cover early in the season help.

Flowers and fruit set

Most cucumbers make separate male and female flowers, and bees carry pollen between them. Fruit from poorly pollinated flowers grows misshapen, narrow or curled at one end.

Some modern varieties set fruit with no pollination at all. These parthenocarpic varieties, such as Diva, produce seedless fruit and are a smart choice for greenhouses and for cool, cloudy summers when bees are scarce. Other hybrids are mostly female and come with a few marked seeds of a pollinator variety; plant those too.

Water and bitterness

Cucumbers are about 95 percent water, so they need steady moisture, about an inch a week, more in hot weather. Bitter cucumbers come from natural compounds called cucurbitacins, which increase when plants are stressed by heat, drought or uneven watering. The bitterness concentrates near the stem end and in the skin. Even watering prevents most of it, and burpless varieties are bred to be low in these compounds.

Soil and disease

Grow them in rich, well-drained soil with a pH of about 6.0 to 7.0. Trellising keeps fruit clean and straight and improves airflow, which slows powdery mildew in late summer. Resistant varieties like Marketmore 76 hold up longer. Slugs are the main threat to seedlings here.

Harvest and storage

Pick slicers at 6 to 8 inches and picklers at 2 to 4, checking every day or two. Leaving a mature, yellowing cucumber on the vine signals the plant to stop setting new ones. Cucumbers are chill-sensitive, so they keep best around 50 to 55°F; in the fridge, use them within a few days before they soften and pit.

Good neighbors and crop rotation

Good neighbors

  • Dill. Grows alongside and is ready when you're pickling.
  • Bush beans and lettuce. Grow beneath a trellised cucumber vine.

Squash family: Move squash, pumpkins, cucumbers and melons to a new bed each year and return every three years, so soil-borne wilts and root rots don't build up. Clear and compost (or bin) mildewed vines in fall.

Pests and problems

What most often goes wrong with cucumbers in Northwest gardens, how to spot it and what to do.

Powdery mildew

Signs: White powder on the leaves from late summer.

What to do: Choose resistant varieties, trellis the vines and water at the base.

Cucumber beetles

Signs: Yellow-and-black beetles chewing leaves and flowers.

What to do: Row cover until flowering, then remove it for bees.

Bitter or misshapen fruit

Signs: Bitter skin, or fruit that's fat at one end.

What to do: Water deeply and evenly, and give bees access to the flowers.

Common questions about growing cucumbers

When should I plant cucumbers in Oregon, Washington and Idaho?

Plant in the garden: May 15 – Jun 12 in Portland and Seattle, May 20 – Jun 17 in Spokane, May 1–29 in Boise and Jun 9 – Jul 7 in Bend. Pick your town at the top of the page for your own dates.

Why are my cucumbers bitter?

Bitterness comes from natural compounds called cucurbitacins, which build up when plants are stressed by heat, drought or uneven watering. Water deeply and regularly, and try burpless varieties. Peeling and trimming the stem end removes most of it.

Why are my cucumbers curled or misshapen?

Usually incomplete pollination, often in cool or cloudy weather when bees aren't active. Uneven watering contributes too. Parthenocarpic varieties, which set fruit without pollination, avoid the problem.

Can I grow cucumbers in a cool summer?

Yes. Wait for warm soil, use black plastic mulch and row cover early, trellis the vines in your sunniest spot, and choose parthenocarpic or fast-maturing varieties. A greenhouse or hoop house makes them very reliable.

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