Broccoli illustration 🥦

🥦 Growing Broccoli in Zone 3a

Zone 3a has harsh winters and a short growing season. Start Broccoli early indoors to maximize your harvest window. Last frost: May 22. First frost: Sep 12.

Planting Calendar

Indoor
Outdoor
Harvest
Apr 10Sep 12

Season: May 22 – Sep 12 (113 days)

Zone3a
Last FrostMay 22
First FrostSep 12
Season Length113 days
Days to Harvest70
SunFull Sun
Frost ToleranceHeavy
Spacing1/sqft (12" apart)

When to Plant Broccoli in Zone 3a

Start Seeds Indoors: Apr 10

Start Broccoli seeds indoors around Apr 10 (6 weeks before last frost). Optimal germination temperature: 75°F. Germinates in 5–10 days.

Transplant Outdoors: Jun 5

Transplant Broccoli seedlings outdoors after Jun 5. Wait until soil temperature reaches 50°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: Aug 4

First harvest approximately Aug 4 (~60 days from transplant). Continue harvesting until first frost (Sep 12).

Fall Planting: Jun 20

For a fall harvest, plant Broccoli around Jun 20 (12 weeks before first frost).

Companion Planting

❌ Strawberries❌ Tomatoes❌ Beans

Plan Your Broccoli Garden

Track Broccoli from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.

Start Free Broccoli Growing Guide