Broccoli is a hardy vegetable of the cabbage family that is high in vitamins A and D. It develops best during cool seasons of the year.
When broccoli plants of most varieties are properly grown and harvested, they can yield over an extended period. Side heads develop after the large, central head is removed. Two crops per year (spring and fall) may be grown in most parts of the country. New heat tolerant varieties allow broccoli to be produced in all but the hottest parts of the season.
Transplants are recommended to give the best start for spring planting, because transplanting gets the plants established more quickly. Thus they can bear their crop with minimal interference from the extreme heat of early summer. Fall crops may be direct-seeded in the garden if space allows or may be started in flats to replace early crops when their harvest ends.
Cruiser (58 days to harvest; uniform, high yield; tolerant of dry conditions)
Green Comet (55 days; early; heat tolerant)
Green Goliath (60 days; spring, summer or fall; tolerant of extremes)
When to Plant
Transplant young, vigorously growing plants in early spring. Plants that remain too long in seed flats may produce "button" heads soon after planting. For fall crops, buy or grow your own transplants or plant seeds directly in the garden. For fall planting, start seedlings in midsummer for transplanting into the garden in late summer. To determine the best time for setting your fall transplants, count backward from the first fall frost in your area and add about 10 to the days to harvest from transplants. Remember that time from seed to transplant is not included in this figure.
Spacing & Depth
Plant seeds 1/4 to 1/2 inch deep, or set transplants slightly deeper than they were grown originally. Plant or thin seedlings 18 to 24 inches apart in the row and allow 36 inches between rows. Broccoli plants grow upright, often reaching a height of 2 1/2 feet. Space plants one foot apart in all directions in beds.
Use starter fertilizer for transplants and side-dress with nitrogen fertilizer when the plants are half grown. Provide ample soil moisture, especially as the heads develop.
The edible part of broccoli are compact clusters of unopened flower buds and the attached portion of stem. The green buds develop first in one large central head and later in several smaller side shoots. Cut the central head with 5 to 6 inches of stem, after the head is fully developed, but before it begins to loosen and separate and the individual flowers start to open (show bright yellow). Removing the central head stimulates the side shoots to develop for later pickings. These side shoots grow from the axils of the lower leaves. You usually can continue to harvest broccoli for several weeks.
Aphids — Watch for buildup of colonies of aphids on the undersides of the leaves.
For more information on aphids, see our feature in the Bug Review.
Cabbage worms — Three species of cabbage worms (imported cabbage worms, cabbage loopers and diamond back moth worms) commonly attack the leaves and heads of cabbage and related cole crops. Imported cabbage worms are velvety green caterpillars. The moth is white and commonly is seen during the day hovering over plants in the garden. Cabbage loopers ("measuring worms") are smooth, light green caterpillars. The cabbage looper crawls by doubling up (to form a loop) and then moving the front of its body forward. The moth is brown and is most active at night. Diamondback worms are small, pale, green caterpillars that are pointed on both ends. The moth is gray, with diamond-shaped markings when the wings are closed. The damage caused by diamondback larvae looks like shot holes in the leaf.
The larval or worm stages of these insects cause damage by eating holes in the leaves and cabbage head. The adult moths or butterflies lay their eggs on the leaves but otherwise do not damage the plants. The worms are not easy to see because they are fairly small and blend with the cabbage leaves. Cabbage worms are quite destructive and can ruin the crop if not controlled. They are even worse in fall plantings than in spring gardens because the population has had several months to increase. About the time of the first frost in the fall, moth and caterpillar numbers finally begin to decline drastically.
For more information on cabbage worms, see our feature in the Bug Review.
Questions & Answers
Q. How large should the central head of broccoli grow before cutting?
A. Harvest the central head when the individual florets begin to enlarge and develop and before flowering begins. Size varies with variety, growing conditions and season of growth; but central heads should grow to be 4 to 6 inches in diameter, or even larger. Late side shoots may reach only 1 to 2 inches in diameter.
Q. What causes small plants, poor heading and early flowering?
A. Yellow flowers may appear before the heads are ready to harvest during periods of high temperatures. Planting too late in the spring or failing to give the plants a good start contributes to this condition. Premature flower development also may be caused by interrupted growth resulting from extended chilling of young plants, extremely early planting, holding plants in a garden center until they are too old or too dry, and severe drought conditions. Small heads that form soon after plants are set in the garden are called "buttons" and usually result from mistreated seedlings being held too long or improperly before sale or planting. Applying a starter fertilizer at transplanting gets the plants off to a good start but cannot correct all the difficulties mentioned.
Selection & Storage
Since broccoli grows best in cool weather, your garden plan should produce a fall and spring harvest. The large central head is the spring harvest and smaller side shoots will be ready in the fall. Harvest when the head is large and firm, with a compact cluster of small flower buds with none open enough to show bright yellow flowers. Look for bright green or purplish-green heads. Yellow flowers and enlarged buds are signs of over-maturity.
Store the broccoli, unwashed, in loose or perforated plastic bags in the vegetable crisper of the refrigerator. Broccoli left unrefrigerated quickly becomes fibrous and woody. Wet broccoli quickly becomes limp and moldy in the refrigerator—so wash it just before using. Store fresh broccoli in the refrigerator for 3-5 days. Old broccoli may look fine, but it develops strong undesirable flavors. It tastes best and is highest in nutritional value when storage time is brief.
Nutritional Value & Health Benefits
A member of the cabbage family and a close relative of cauliflower, broccoli packs more nutrients than any other vegetable. Broccoli contains large amounts of vitamin C and beta carotene which are important antioxidants. In the United States, broccoli has become the most favored cruciferous vegetable (cauliflower, Brussels Sprouts, and all forms of cabbage). Researchers have concluded that broccoli and other cruciferous vegetables should be included in the diet several times a week. Consuming foods high in antioxidants can reduce the risk of some forms of cancer and heart disease. One half cup cooked broccoli contains the following nutrients as well as many other trace nutrients and phytochemicals.
Nutrition Facts (1/2 cup cooked fresh broccoli)
Dietary fiber 2.4 grams
Protein 2.3 grams
Carbohydrates 4.3 mg
Vitamin C 49 mg
Folic Acid 53.3 nanograms
Calcium 89 mg
Iron 0.9 mg
Preparation & Serving
Wash broccoli under cool running water. Never allow it to sit in water as it will lose water soluble nutrients. Fresh broccoli is delicious raw or cooked. Trim and peel the stalk, it is high in fiber. Cut the florets into uniform pieces for even cooking. Overcooked broccoli develops a strong sulfur odor. Steam broccoli for 3-4 minutes or simmer in about one inch of boiling water for the same amount of time or less. Cooked broccoli should be bright green and tender-crisp. Overcooked broccoli turns dark green and suffers nutrient loss, especially vitamin C.
Freezing is the best way to preserve broccoli. Broccoli, as well as all other broccoli vegetables, must be blanched (scalded) in boiling water before freezing. Unblanched vegetables contain an active enzyme which causes toughening and severe flavor and nutrient loss during freezing. Blanching retards the enzyme activity.
Freezing does not improve the quality of any vegetable. Freezing actually can magnify undesirable characteristics. For instance woodiness in stalks become more noticeable upon thawing. Select broccoli that has grown under favorable conditions and prepare for freezing as soon after picking as possible. Broccoli at its peak quality for eating will produce best results in the freezer.
In a blanching pot or large pot with a tight fitting lid, bring 5 quarts of water to a rolling boil.
Meanwhile, wash broccoli, trim stalks and cut through florets so that pieces of heads are not more than 1 inch across. Peel stalks and cut into rounds or quarter lengthwise.
Blanch no more than one pound at a time. Add broccoli to boiling water and immediately cover with a tight fitting lid.
Start timing immediately and blanch for four minutes.
Prepare an ice water bath in a large 5-quart container or the sink.
Remove broccoli from water with a slotted spoon or blanching basket.
Emerge in the ice water bath for five minutes or until cooled. If you do not have ice, use several changes of cold water or running cold water. Remove and drain.
Pack cold broccoli in zip-closure freezer bags or freezer containers. Squeeze out as much air as possible before sealing bags.
Label and date each container or bag. Immediately place in the freezer, allowing an inch of space around each container until it is frozen. Freeze for up to one year at 0 degrees F. or below.
Blanching water can be reused. Add more water if necessary. Remember to always bring water back to a rolling boil before blanching more broccoli.
Herbs and spices that enhance the flavor of broccoli include basil, dill, garlic, lemon balm, marjoram, oregano, tarragon and thyme.
Steamed Broccoli with Lemon-Dill Dressing
- 1 bunch broccoli (about 2 pounds)
- 3 carrots, peeled and cut into 2 -inch strips
- 6 tablespoons olive oil
- 2 tablespoons lemon juice
- zest of one lemon, grated or minced
- 1/4 teaspoon black pepper (optional)
- 1 teaspoon dried dill weed or 3 teaspoons fresh dill
- salt to taste
Wash, trim stems from broccoli and peel, cut into strips the same size as carrots. Cut florets into small uniform pieces and set aside. Prepare carrots and set aside. Bring a large saucepan of water to a boil. (Or prepare the steamer) Add carrots and broccoli stems. Cook for one minute. Add broccoli florets and boil two minutes longer. Do not over cook. Drain, and rinse under cold running water, drain again. Place in a large bowl and gently toss with dressing. Serve immediately.
Makes six servings.
- 2 tablespoons toasted sesame seed oil
- 1/2 cup walnuts, broken or chopped coarsely
- 1/4 cup chopped green onions with tops (optional)
- 4 cups broccoli florets
- 1/4 cup red pepper strips
- 2 tablespoons lite soy sauce
In a large heavy, skillet heat oil until hot. Add walnuts and onions and stir-fry for one minute tossing constantly. Add broccoli and continue to toss for three to four minutes. Add red pepper strips and soy sauce and continue to cook one minute longer. Serve immediately. Makes six servings.