Rainline Garden My garden plan
A head of broccoli growing among its large leaves
Photo: Pexels

When to plant broccoli in John Day, OR

Start broccoli from seed indoors Mar 12–26, then plant the young plants in the garden in John Day Apr 30 – Jun 4. For a fall harvest, plant again Jun 26 – Jul 10.

Moderate Plant young plants (starts)

Difficulty
Moderate
Sun
Full sun
Spacing
18 inches apart
Planting depth
Plant starts at the depth they grew in the pot
Frost
Handles light frost
First harvest
About 70 days after planting

Why these dates

John Day's typical last spring frost is May 28. As a cool-season crop that handles light frost, this crop can go in about 4 weeks before that.

High desert and mountains. Central and high eastern Oregon. Frost is possible almost any month. Use row covers, wall-o-water or cloches for warm crops, and choose short-season varieties.

How to grow broccoli in John Day

  1. Start seeds indoors Mar 12–26 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 Apr 30 – Jun 4, 18 inches apart. Plant starts at the depth they grew in the pot.
  4. Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
  5. Plant again Jun 26 – Jul 10 for a fall harvest.
  6. Harvest: Cut the main head while the buds are tight and dark green. Side shoots follow for weeks.

Key numbers

Growing notes

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

Soil and feeding

Broccoli is a hungry plant. Give it rich soil with a few inches of compost and a balanced vegetable fertilizer at planting, then a light side-dressing of nitrogen about a month later as heads begin to form. Aim for a pH of 6.0 to 7.0. Many Northwest soils west of the Cascades are naturally acidic, and liming toward the upper end of that range also helps discourage clubroot, a soil disease that causes swollen, knotted roots and wilting plants.

Why broccoli flowers early or makes tiny heads

Broccoli heads are flower buds, so anything that pushes the plant to bloom early ruins the crop. Stress is the usual cause: transplants left too long in small pots, a hard cold snap right after planting, or dry soil. The plant gives up on growing big and makes a small, early head that quickly opens into yellow flowers. Plant young, healthy starts, keep them watered, and harvest as soon as the head looks full with buds still tight. Fall crops planted in mid to late summer often give the best heads in the Northwest, because they mature in cool weather.

Worms, aphids, and harvest

The green caterpillars on broccoli come from the small white butterflies seen all summer. Insect netting stops them from laying eggs, and that's easier than picking worms out of the florets later. Gray aphids hide in the heads in late summer; check often and spray them off with water. After cutting the main head, leave the plant in place, since side shoots keep coming for weeks. Purple Sprouting is planted in summer and overwinters west of the Cascades for a spring harvest. Store broccoli unwashed in a bag in the fridge for about a week.

Common questions

When is the last frost in John Day, OR?

Typically May 28. In 9 years out of 10, frost is over by June 15. These are 1991–2020 NOAA climate normals for John Day.

Is it too late to plant broccoli in John Day?

The spring planting window runs through June 4. If you miss it, plant again for fall from June 26 to July 10.

When should I start broccoli from seed indoors in John Day?

March 12 to March 26, which is 7 to 5 weeks before the April 30 planting date. Or buy young plants at a garden center instead.

Why is my broccoli flowering before the head gets big?

The plant was stressed, usually by heat, dry soil, or being root-bound in its pot before planting. Once the yellow flowers open, the head won't improve, so cut it and eat what you can. Next time plant younger starts and keep the soil evenly moist.

Does broccoli grow back after you cut it?

Not a new main head, but most varieties send up smaller side shoots for several weeks. Cut the main head with a slanted cut, leaving the plant and its leaves in place. Keep watering and the shoots will keep coming.

How do I get rid of worms in my broccoli?

Soak cut heads in cool salty water for 15 minutes and the caterpillars float out. To prevent them, cover plants with insect netting from planting day. Organic sprays made from Bt (Bacillus thuringiensis) also work on small caterpillars without harming people or pets.

Also plant in John Day around the same time

Planting dates for broccoli in nearby areas

Full planting calendar for John Day · Broccoli in every city