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Kohlrabi bulbs swelling above the soil in a garden row

Oregon · Washington · Idaho

When to plant kohlrabi

Plant in the garden: Portland and Seattle Mar 15 – Apr 26; Spokane Apr 15 – May 27; Boise Apr 1 – May 13; Bend May 12 – Jun 23.

Kohlrabi is a cabbage relative grown for its swollen stem, a round bulb that sits above the soil with leaves sprouting from it. Peeled, it's crisp and mild, somewhere between broccoli stem and apple, eaten raw in slaws and sticks or roasted. It comes in pale green and purple, and both are white inside.

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

Difficulty
Easy
Sun
Full sun
Spacing
Thin to 6 inches apart
Planting depth
¼ to ½ inch deep
Frost
Handles light frost
First harvest
About 55 days after planting

Pick when the bulb is about tennis-ball size; bigger ones turn woody.

Kohlrabi planting dates

TownsStart seeds indoorsPlant in the gardenPlant again for fall
Portland, OR, Seattle and Tacoma, WAFeb 1–15Mar 15 – Apr 26Aug 13–27
Spokane, WAMar 4–18Apr 15 – May 27Aug 10–24
Boise and Meridian, ID, Astoria, ORFeb 18 – Mar 4Apr 1 – May 13Aug 13–27
Bend and Redmond, ORMar 31 – Apr 14May 12 – Jun 23Jul 13–27

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.

Kohlrabi year at a glance

TaskJFMAMJJASOND
Start indoorsFeb
PlantMarAprAug
HarvestMayJunOctNov

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 kohlrabi

  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, Thin to 6 inches apart. If you plant seeds instead, sow them ¼ to ½ inch deep.
  4. Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
  5. Plant again on your city's dates for a fall harvest.
  6. Harvest: Cut bulbs at 2 to 3 inches across. Peel off the tough skin and eat raw or cooked.

Growing kohlrabi 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

Kohlrabi grows fast in spring and fall. Pick it at tennis-ball size before it turns woody.

Coast

Oregon and Washington coast

Cool summers keep kohlrabi tender over a longer harvest window.

East of the Cascades

Columbia Basin, Yakima, Boise, Spokane, north Idaho

Hot weather makes kohlrabi tough and woody, so time it for spring and fall and water steadily.

High desert and mountain towns

Central Oregon, high eastern Oregon valleys, McCall, Salmon

Kohlrabi tolerates frost and grows well in the cool summers.

Kohlrabi in a Northwest garden

More kohlrabi varieties

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

Kolibri

Hybrid, purple · 45 days

Deep purple bulbs with crisp, sweet white flesh. Quick and uniform, it stays tender when picked at the right size.

Both sides

Winner

Hybrid, green · 45 days

Smooth, pale green, slightly flattened bulbs that are slow to turn woody. Sweet and crisp, it is a dependable all-around choice for spring and fall.

Both sides

Kossak

Hybrid, giant storage · 80 days

A giant that can grow 8 inches or more across and still stay tender. Bulbs store for months, making it a good fall crop for winter use.

Both sides

Early White Vienna

Heirloom, green · 55 days

The classic open-pollinated kohlrabi with pale green skin and mild, crisp flesh. An inexpensive, easy choice for beginners. Pick bulbs small for the best texture.

Both sides

Early Purple Vienna

Heirloom, purple · 60 days

Purple skin over white, sweet flesh, a little slower than its white counterpart. A colorful, reliable open-pollinated option. It is a good choice for fall crops too.

Both sides

How much to grow

How many to plant

For a family of four, 10 to 15 plants per planting.

What to expect

One bulb per plant.

Storing the harvest

Remove leaves and keep bulbs in the fridge for several weeks.

What to plant after kohlrabi

Around Portland, the kohlrabi harvest wraps up around June. 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 steadily and harvest when bulbs are 2 to 3 inches across, before they turn woody.

Growing notes

What makes the difference in Northwest gardens, in plain language.

Soil and steady growth

Kohlrabi is in the cabbage family, and the bulb is actually a swollen stem that sits above the soil. It wants fertile soil with compost, a pH of about 6.0 to 7.5, and steady moisture. Feed lightly at planting. The key to a tender bulb is fast, uninterrupted growth: dry spells or heat make the flesh fibrous. Mulch once plants are up to keep the soil evenly moist.

Timing and why bulbs get woody

Kohlrabi is quick, about two months from seed, and prefers cool weather. Spring crops should go in early, and starts set out too early into a long cold spell may bolt instead of forming a bulb. In the Northwest, fall crops sown in midsummer are especially reliable. Bulbs turn woody when left too long or when grown in hot weather, so pick at tennis-ball size. Kossak is an exception: it's bred to grow large while staying tender, and it stores well. East of the Cascades, get spring crops in early to beat the heat.

Pests, harvest and storage

Cabbage worms chew the leaves; insect netting keeps the white butterflies from laying eggs. Root maggots and flea beetles can also show up, and the same cover helps. Cut the stem just below the bulb when it reaches 2 to 3 inches across. Remove the leaves (young ones are good cooked), peel the tough outer skin, and eat it raw or cooked. Bulbs keep several weeks in a bag in the fridge, and longer for large storage types.

Good neighbors and crop rotation

Good neighbors

  • Lettuce and beets. Similar size and timing.

Keep apart

  • Other cabbage-family crops in the same bed every year. Shared pests and clubroot build up; rotate.

Cabbage family: Grow cabbage-family crops in a different bed each year and come back to the same spot only every three or four years. Clubroot, which swells and knots the roots, lives in the soil for many years once it arrives, and root maggot pupae wait in last year's bed.

Pests and problems

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

Cabbage worms

Signs: Holes in leaves.

What to do: Insect netting from planting.

Woody bulbs

Signs: Tough, fibrous bulbs.

What to do: Harvest at 2 to 3 inches across and water evenly.

Common questions about growing kohlrabi

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

Plant in the garden: Mar 15 – Apr 26 in Portland and Seattle, Apr 15 – May 27 in Spokane, Apr 1 – May 13 in Boise and May 12 – Jun 23 in Bend. Pick your town at the top of the page for your own dates.

Why is my kohlrabi woody?

It was likely left to grow too big, grown in hot weather, or short on water. Pick at about tennis-ball size and keep the soil evenly moist. Cool-season crops are the most tender.

How do you know when kohlrabi is ready?

When the bulb is 2 to 3 inches across, usually about two months after sowing. Cut it at the base. Don't wait too long, since bigger bulbs toughen quickly.

What part of kohlrabi do you eat?

Mainly the round bulb, which is a swollen stem. Peel off the tough skin and eat it raw like an apple-crisp radish or cooked. The young leaves can be cooked like kale.

Also on these lists:

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