Broccoli is a shade-tolerant vegetable that does well in container gardens. It is a member of the cole or cabbage family, which includes Brussels sprouts, kale, cauliflower, collards and kohlrabi. Broccoli is a nutritious vegetable high in vitamins, minerals and antioxidants. It is a cool-season vegetable that does best when the temperature is between 65 and 80 degrees Fahrenheit. Harvest broccoli when the buds are tight and have not begun to turn yellow.
A single broccoli plant may be grown successfully in a clay pot 7 to 12 inches in height. Half-barrels are sold at garden centers for water features and fish ponds and they also make good container gardens. Three traditional broccoli plants or five to seven of the Broccoli Rabe variety can be grown in a half barrel. Tubs, boxes, empty rice bags (20 lb. or more) or 5-gallon pails can also be used as container gardens.
The planting medium in a container garden needs to be well-drained, well-aerated and provide a constant supply of nutrients to the growing broccoli plants. Garden soil alone is too heavy, dense and compact for container use. Mix 1/3 commercial or homemade mature compost, 1/3 leaf mold and 1/3 garden soil for a good growing medium for broccoli. Organic soil mixes are also available at garden centers.
Companion planting is the science of placing mutually beneficial plants in close proximity to each other in the garden. A number of plants act as deterrents to white flies and other pests harmful to broccoli. Herbs such as chives, garlic and oregano can be grown between the broccoli plants to repel insect pests. Beets, spinach and chard also provide mutually beneficial protection for broccoli.
Broccoli grown in containers needs more frequent watering. Composted soil helps retain water, and a layer of mulch on the soil surface also reduces water evaporation. Gauge the water needs of broccoli by sticking your finger in the soil. If the soil sticks to your finger, the broccoli plant does not need water. Check daily during hot weather and water as needed.
Compost used as part of the soil mixture is also a time-release fertilizer. The micronutrients in compost are released on an "as-needed" basis to the growing plant. Nonorganic fertilizers can easily burn tender root systems because of the sudden influx of high levels of nitrogen they give. Feed container broccoli plants with organic compost as a side dressing around the plant base one time at midseason.