Imperial Broccoli is an F1 hybrid bred for heat tolerance, a trait that sets it apart in the often-finicky broccoli world. Maturing in just 66 days from transplant, this compact variety reaches 12-18 inches tall and produces tight, dense heads ready to harvest before they flower. Hardy from zones 3 to 13, it thrives in full sun with consistent moisture and well-draining, fertile soil kept between pH 6.0 and 7.0. While broccoli traditionally struggles in hot weather, Imperial's improved heat tolerance expands the window for success, making spring and fall crops far more reliable.
Full Sun
High
3-13
18in H x ?in W
—
High
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Imperial's real strength lies in its hybrid vigor and heat resilience. The variety reaches maturity quickly at 66 days, and its compact growth habit means you can space plants just 4 inches apart in rows 18 inches wide, fitting more into a smaller footprint than traditional varieties. Harvest the central head when it's tight and dense, then the plant rewards you with side-shoots that keep producing if you cut them regularly, extending your harvest well beyond that first 66-day window.
Imperial Broccoli is grown for its edible florets, which are rich in vitamins C and K, plus B-complex vitamins and minerals. The primary harvest is the central head, cut with at least 6 inches of stem. After the main head is removed, the plant continues to produce side-shoots that can be harvested regularly throughout the season. Broccoli is used fresh in salads, steamed, roasted, stir-fried, or added to soups and grain dishes. The calcium in broccoli is also notably more bioavailable than calcium from dairy sources, making it nutritionally significant beyond its culinary appeal.
No timeline data available yet for this variety.
Start seeds indoors in a warm environment (70-85°F). Johnny's Selected Seeds reports approximately 850 viable plants per 1,000 seeds. Transplant seedlings outdoors once they reach a sturdy size, typically 3-4 weeks after sowing, depending on indoor conditions.
Transplant seedlings outdoors when they are established and the soil temperature supports growth. Plant 4 inches apart within rows spaced 18 inches apart. The 66-day days-to-maturity count begins from the date of transplanting, so time your transplants for spring or fall crops when temperatures are cooler.
Direct seed can be sown in spring or fall. Add 25-35 days to the listed 66-day maturity window if direct seeding rather than transplanting, since that timeline is calculated from transplant date.
Harvest the central head when it is tight and dense, before the florets begin to flower or yellow petals appear. Use a clean, sharp knife to remove the head with at least 6 inches of stem, cutting at a slant to shed water. Once the main head is harvested, continue cutting side-shoots regularly to encourage further production. Harvest immediately if you notice yellow petals beginning to show, as the head is past its peak.
After harvesting the central head with a clean, sharp knife (cutting at least 6 inches of stem at a slant to prevent water pooling), regularly cut the side-shoots that emerge from the remaining stem. This encourages continued production and extends your harvest season significantly.
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