Growing Broccoli in the Home Garden

Broccoli is among the many "cole crops" grown in the home vegetable garden.  Cole crops is a general term used to describe several vegetables in the mustard family, including broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, and kohlrabi. All cole crops are cultivated varieties of the species Brassica oleracea. Cole crops are cool-season vegetables that grow best at temperatures between 60° and 70°F and can withstand light frosts without injury.  

Suggested Cultivars  |  Planting  |  Care  |  Potential Problems  |  Harvest & Storage  |  More Information

Broccoli Green Magic
Broccoli 'Green Magic'

Suggested Cultivars for Iowa

  • Arcadia – late (fall production); small domed heads
  • Goliath – large, tight heads
  • Green Magic – medium-size, blue-green heads; good heat tolerance
  • Gypsy – mid-season; heat tolerant
  • Imperial – late maturing; dark green heads; good heat tolerance
  • Marathon – late maturing; blue-green heads
  • Packman – early to mid-season; uniform, large heads


Broccoli is best started by seed indoors, and transplants are planted in the garden in early spring.  A second crop can be planted in mid-to-late summer for fall harvest.


Plant broccoli in the garden in mid-April in central Iowa.  (Gardeners in southern Iowa can plant in early April, while those in northern counties should wait until late April.)  Sow seeds indoors 4 to 5 weeks before planting outdoors or purchase young, stocky transplants at a greenhouse or garden center.  Harden or acclimate the transplants outdoors for several days before planting.  Initially place plants in a shady, protected location and then gradually expose them to longer periods of sunlight.  Depending on the cultivar, plants are ready to harvest 60-75 days after transplanting.  This is typically mid-June to mid-July.

For a fall crop, plant transplants in the garden anytime between late June and early August.  Start transplants indoors 4 to 5 weeks before planting outdoors.  Harvest can be expected from mid-September to late October, depending on when transplants were planted in the garden.


Cole crops, like broccoli, perform best in fertile, moist, well-drained soils. An ideal soil pH is between 6 and 7. The planting site should also receive at least 6 hours of direct sun each day.  To avoid disease problems, rotate the placement of cole crops in the garden.  If possible, plant cole crops in a given area only once every 3 or 4 years.


When planting cole crops in the garden, space plants 18 to 24 inches apart within the row.  Rows should be approximately 24 to 30 inches apart.  



Most cole crops, such as broccoli, have shallow root systems and require weekly irrigation if rainfall doesn’t provide one inch of water per week.  If possible use soaker hoses or drip irrigation systems to prevent wetting the foliage.  Watering only the plant's root zone can also reduce the number of weeds that may germinate.  Learn more about watering in this article: Watering Tips for the Garden, Lawn, and Landscape.


If a soil test has not been done, apply 1-2 pounds of all-purpose garden fertilizer, such as 10-10-10, per 100 square feet, and incorporate it into the top 4-6 inches of soil before planting.  Conduct a soil test to get more precise fertilizer recommendations based on your garden's fertility. 

About 3-4 weeks after planting, broadcast a small amount of an all-purpose garden fertilizer in a band along one side of each row.

Mulching & Weeding

Control weeds to prevent competition for water, nutrients, and light. Shallow cultivation, hand pulling, and mulching are the best weed control options.
A 2-3 inch layer of mulch, such as straw, dry grass clippings, or shredded leaves, helps control weeds and conserves soil moisture. Learn more about weed control in this vegetable garden in this article: Weed Control in the Vegetable Garden.

Potential Problems


Broccoli plants exposed to stressful growing conditions may form heads prematurely. This development is called buttoning. Stressful conditions that
may lead to buttoning include exposure to prolonged periods of temperatures below 50°F, dry conditions, and infertile soils. Also, large (older) rootbound transplants are more likely to button than young plants. Plants that button do not form usable heads.


Cabbageworms are greenish caterpillars that eat large, irregular holes in the foliage of most cole crops. Treat when caterpillars are first noticed with products containing Bacillus thuringiensis (Bt). When consumed by cabbageworms, this bacterium produces toxins which destroy the insects. Synthetic and other organic pesticides also can be used.

Flea Beetles

Flea beetles eat small, round holes in the foliage, resulting in “shothole” damage.  Adults are tiny, shiny, black beetles.  They possess large hind legs that enable them to jump.   

Minor flea beetle damage will have little effect on crop yields.  If significant damage begins to appear, treat plants with an insecticide.  As always, carefully read and follow label directions when using pesticides.  

No Crown or Head

Hot weather (86°F or more during the day and 77°F or more at night) can prevent broccoli from forming heads or crowns.  Avoid planting broccoli too late in the spring.  Earlier planting means they can mature and produce crowns before hot temperatures arrive.  If temperatures cool down, plants may produce a crown.

Harvest & Storage

Broccoli is typically ready to harvest 60-75 days after planting transplants in the garden.  

Broccoli should be harvested when the head is fully developed but before the small yellow flower buds start to open. At harvest, the terminal head should be tight, blue-green, and approximately 6 to 7 inches in diameter. Cut the central stem just below the head. Several smaller side heads (about 1 to 3 inches across) will develop in the axils of the leaves after the central head is removed.

Broccoli may be placed in a perforated plastic bag and stored in the refrigerator for 10 to 14 days.

With good management practices, the average yield per 10-foot row of broccoli is 8-12 pounds. 

More Information

Last reviewed:
April 2024