When to Plant Broccoli in Zone 5

Broccoli timing in zone 5

Most of zone 5 sees its last spring frost between May 2 and May 17 (typical May 8) and its first fall frost between September 28 and October 7 (typical October 2). Broccoli handles light frost, but long cold spells on young plants can cause tiny, early heads. The tool above uses the weather station closest to your ZIP code.

Why broccoli is planted before the last frost

Broccoli is a cool-season crop. It tolerates light frost and forms its best heads in mild weather. In heat, heads loosen and the yellow flowers open early. That is why transplants go out two to four weeks before the last spring frost, and why broccoli is grown again in late summer for a fall harvest.

Best broccoli varieties for zone 5

Broccoli likes cool weather, so zone 5 grows it well in both spring and fall. Choose by type:

• Heading broccoli: the familiar large central head, followed by side shoots.
• Sprouting broccoli: many small heads instead of one big one.
• Romanesco: lime-green spiraled heads that need a long, cool season.

Look for the days to maturity on the packet: most heading types are ready 55–65 days after transplanting.

How to plant broccoli

1. Start seeds indoors four to six weeks before transplanting, ¼–½ inch deep.
2. Transplant young, vigorous plants. Avoid plants that are overgrown or dried out in their pots.
3. Space plants 16–24 inches apart in rows 24–36 inches apart.
4. Use a starter fertilizer at planting, then side-dress three weeks later.
5. Keep the soil evenly moist. Severe drought causes small heads.

Zone 5 broccoli tips

• Plant young, vigorous transplants. Plants left too long in their pots, or chilled for weeks after planting, tend to form small “button” heads.
• Don’t plant too early. Temperatures below 45 °F for long periods can stop heading or cause bolting.
• Feed for side shoots. Side-dress after cutting the main head, and the plant keeps producing smaller heads for weeks.
• Watch for cabbage worms. Green caterpillars chew holes in the leaves. Check under the leaves often.

Harvesting broccoli

Cut the main head when it is 4–6 inches across and the buds are tight and green, before any yellow flowers appear. Leave 5–6 inches of stem. Side shoots then grow from the leaf joints and give you smaller heads for several weeks. Most heading broccoli is ready 55–65 days after transplanting.

Broccoli planting dates in nearby zones

• Zone 4April 18 – May 2
• Zone 6April 3 – April 17

See dates for every zone on the broccoli planting guide, or build a full schedule with the planting calendar.