When to Plant Brussels Sprout in Montana

Growing Brussels Sprout in Montana: Complete Guide

Brussels Sprout (Brassica oleracea var. gemmifera) is a warm-season crop that needs a head start indoors before Montana's last frost. Depending on your zone, Montana gardeners start seeds indoors between January 21, 2027 (Zone 6b) and February 25, 2027 (Zone 3b), then move transplants outside once their zone's last frost has passed — the zone table above has your exact dates.

Because Montana stretches across 7 USDA hardiness zones (3b, 4a, 4b, 5a, 5b, 6a, 6b), 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 84 days to maturity, Brussels Sprout needs the indoor head start that Montana's growing season requires. Starting indoors ensures you have strong transplants ready the moment outdoor conditions are right.

Brussels Sprout requires full sun and regular 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 Montana.