What Is Required to Grow Broccoli?

Timing and Soil

• Broccoli grows best in the spring when planted as transplants. For a fall crop, plant broccoli seeds directly in the garden. Broccoli transplants also can be planted in the garden during the first week of September for a harvest before winter. Depending on the variety, broccoli can take 60 to 100 days to reach maturity. Broccoli requires well-draining soil with a pH of 5.8 to 6.5 for best growth. It prefers fertile sandy loam to clay loam.

Fertilizer

• Fertilizer applications are crucial to broccoli growth. Consider doing a soil test to determine the nutrients in the soil prior to planting the broccoli. Broccoli typically requires adequate nitrogen to grow. The University of Arkansas Division of Agriculture suggests using 8 ounces of a water-soluble 20-20-20 fertilizer per plant when transplanting. The broccoli plants benefit from a side dressing of nitrogen halfway through the plants' growth cycle, when they measure approximately 6 inches tall.

Planting

• Broccoli plants require moist soil, especially when the heads begin to develop. The plants need adequate growth room. Space each plant 18 to 24 inches apart in a row. Locate the rows 36 inches apart. Apply mulch to the soil around the broccoli plants to reduce weed growth. The roots of broccoli plants are shallow and can sustain damage from over cultivation; applying a layer of mulch helps protect the roots.

Temperature

• Stable temperatures of 65 to 75 degrees Fahrenheit allow broccoli to grow best. Plant broccoli in the spring and fall when the weather remains relatively cool. Broccoli does not tolerate temperature fluctuations well; growth becomes dramatic if a 10-day period of temperatures between 35 to 50 degrees occurs after planting, according to the Clemson University Cooperative Extension. The plant prematurely produces flower heads during the excessive growth, which results in a poor crop.