Heat Tolerant Broccoli – What Is A Sun King Broccoli Plant

Sun King Broccoli Plant
sun king
(Image credit: ranmaru_)

The Sun King broccoli plant provides the biggest heads and is certainly among the top producers of broccoli crops. A more heat-tolerant broccoli, you can harvest when the heads are ready, even during the heat of summer, if you must.

Growing Sun King Broccoli

Before getting this broccoli started, choose a planting spot with sun most of the day.

Prepare the ground so it is well-draining with rich soil. Turn soil 8 inches down (20.5 cm.), removing any rocks. Work in compost or a thin layer of well-rotted manure to add organic goodness to the growing bed. A pH of 6.5 to 6.8 is desirable when growing Sun King. If you don’t know your soil pH, it is time to take a soil test.

Don’t plant broccoli where you grew cabbage last year. Do plant at a time that frost may touch your heads. If your area does not experience frost or freezing, you can still plant the Sun King variety since it is more tolerant of warmer conditions.

Broccoli grows winter to spring or fall to early winter, with 60 days to harvest. The best-tasting broccoli matures during cool temperatures and receives a touch of frost. However, if you live in a warm climate without frost, you can grow the heat-tolerant Sun King variety for tasty heads and a worthwhile harvest.

Starting Broccoli Variety Sun King Indoors

Start seeds in a protected area for an earlier harvest. Do this about eight weeks before the last projected night of freezing temperatures. Plant seeds a ¼ inch (0.5 cm.) deep into small cell packs or biodegradable containers in a seed-starting mix or other light, well-draining soil.

Keep the soil moist, never wet. Seedlings sprout in 10-21 days. Once sprouted, place containers under a fluorescent grow light or near a window that receives good sunlight for much of the day. If using a grow light, turn it off for eight hours each night. Plants need nighttime darkness to grow properly.

Young seedlings don’t need as many nutrients as the growing plants you’ll fertilize later in the growth cycle. Feed seedlings about three weeks after sprouting with a half-strength mix of all-purpose fertilizer.

When Sun King seedlings have two to three sets of leaves, it is time to start hardening them off to prepare for outdoor planting. Put them outdoors to get accustomed to current temperatures, starting with an hour a day and gradually increasing their time outside.

When planting Sun King broccoli plants in the garden, put them in rows about one foot apart (30.5 cm.). Make the rows two feet (0.5 m.) apart. Keep the broccoli patch watered, fertilized, and weeded. Mulch or row covers help with weeds, warmth for the roots, and some pest control.

Those in warmer climates can plant in fall and let the broccoli grow during their coolest winter days. Preferred growing temperatures for this plant are 45 to 85 degrees F. (7-29 C.). If temps are at the high end of these guidelines, harvest when the heads develop and tighten up; don’t give it a chance to flower. Leave the plant growing, as edible side shoots often develop on this variety.

Becca Badgett

Becca Badgett was a regular contributor to Gardening Know How for ten years. Co-author of the book How to Grow an EMERGENCY Garden, Becca specializes in succulent and cactus gardening.