When to Plant Broccoli in Idaho

Growing Broccoli in Idaho: Complete Guide

Broccoli (Brassica oleracea var. italica) is a warm-season crop that needs a head start indoors before Idaho's last frost. Most Idaho gardeners begin seeds indoors around Wednesday, March 4, 2026 and move transplants outside around Wednesday, April 15, 2026, after the risk of frost has passed.

Because Idaho stretches across 8 USDA hardiness zones (4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b), planting windows can shift by as much as six to eight weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.

With 60 days to maturity, Broccoli needs the indoor head start that Idaho's growing season requires. Starting indoors ensures you have strong transplants ready the moment outdoor conditions are right.

Broccoli requires full sun (6 hours) and regular (1-1.5 inches/week) moisture. Mountain-state gardens contend with short seasons and intense UV at elevation — cold nights can persist well into June at higher altitudes.

For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Idaho.