Prepare the growing area in the spring after the final spring frost. Cultivate the soil down to a depth of about 6 inches with a garden spade, breaking up large chunks of soil as you work. Add about 4 inches of aged compost or manure to the soil surface and work it in well with the spade. Rake the planting area smooth to finish.
Dig holes for the broccoflower plants with a trowel, spacing the holes about 2 feet apart. Make the holes deep enough to plant the broccoflower at the same depth as they are growing in the temporary containers.
Remove the plants from the containers and place them into the prepared holes. Fill soil in around the roots carefully and tamp down the soil gently with your hands. Water the broccoflower plants immediately after you finish planting them.
Provide water for the plants if less than 1 inch of rain falls in a one-week period. Keep the soil from drying out to prevent stunted plants.
Sprinkle additional compost along the soil near the plants or about 1 tbsp. of nitrogen fertilizer near each plant about four to six weeks after planting. Scratch the compost or nitrogen into the soil with the hand rake and water the soil evenly.
Remove any weeds that appear near the broccoflower plants to keep the weeds from encroaching on the plants. Do not cultivate the soil deeply around the plants, however, or you may disturb the roots.
Harvest the broccoflower heads when they reach a diameter of 6 to 8 inches. Move the leaves gently with your hands and cut the head off the main stem with a sharp knife.