By Dr. Mercola
With each satisfying crunch, broccoli delivers great-tasting nutrition and a slew of health-promoting benefits. It is low in calories and rich in vitamins and minerals. Broccoli also contains fiber, which is vital to your digestive health. As one of the cruciferous vegetables, broccoli is a close relative of Brussel sprouts, cabbage and cauliflower.
Broccoli has twice the vitamin C of an orange and nearly as much calcium as whole milk, with a better rate of absorption. It's also a good source of vitamins A and K. It contains several B vitamins, as well as iron, magnesium, potassium, selenium and zinc. Furthermore, broccoli is an excellent source of phytonutrient glucosinolates, flavonoids and other health-boosting antioxidant and anti-cancer compounds.
According to Mother Earth News,1 "Broccoli is a nutritional superfood that will strengthen your immune system, help maintain strong bones, and help protect you from cancer and heart disease." Learn more about why broccoli is good for you in the video above. While broccoli requires certain growing conditions to thrive, it is a great choice for a home vegetable garden. Here's what you need to know to successfully grow broccoli.
Eight Steps to Successfully Cultivate Broccoli
While you may be able to buy broccoli seedlings from a local nursery, I recommend starting your own plants from organic seeds. It's easy to do, and you will enjoy the process of seeing tiny seeds transformed into hearty plants. In my opinion, nothing tastes better than homegrown vegetables! Rodale's Organic Life2 provides the following tips, which will enable you to successfully cultivate broccoli in your garden or on your patio.
- Start by sowing broccoli seeds indoors seven to nine weeks before the date of the last expected frost
- After germination, which is usually four to five days, maintain your plants under lights or place them in a sunny area with a temperature of 60 to 65 degrees F (16 to 18 degrees C)
- Keep the soil moist but not wet
- To avoid premature heading, seedlings must be about 6 inches, or 15.24 centimeters (cm) tall, with two to four true leaves, before they can be transplanted into your garden
- You must harden the plants for at least one week prior to transplanting
- When transplanting the broccoli seedlings into your garden, be sure to set the plants 1 to 2 inches (2.54 to 5.08 cm) deeper in the garden than they grew in the indoor containers
- Space them 1 to 2 feet (30 to 60 cm) apart in rows that are roughly 2 to 3 feet (60 to 90 cm) apart; proper spacing is important since crowding will result in smaller heads
- Gently pat the soil around each plant
Ideal Growing Conditions for Broccoli
As you make plans to grow your own broccoli, Mother Earth News presents four important aspects that must be considered to create the ideal growing conditions.3
- Season: Broccoli is a cool weather crop, so you'll achieve the best results by growing it in spring or fall. Cool days and nights are essential once broccoli flower heads begin to form. Broccoli grows best when soil temperatures range between 60 to 70 F (16 to 21 C).
- Soil: Broccoli seedlings will thrive when they are planted in compost-rich, well-drained soil. A soil pH between 6.0 to 7.0 is optimal. If using an existing garden bed, be sure to loosen up the top layer of soil, mixing in about 1 inch of mature compost prior to planting.
- Sun: Keep in mind that broccoli prefers full sun. If you live in an area prone to warmer temperatures, a little bit of shade will prevent your broccoli plants from going to seed, also known as bolting.m
- Supplements: To give your broccoli plants an added boost, you may consider supplementing your soil with a high-nitrogen, organic fertilizer like alfalfa meal. If you have access to composted poultry manure, that also works well. Water the soil thoroughly before transplanting seedlings.
Additional Considerations to Ensure a Bountiful Broccoli Crop
When it comes to cultivating broccoli, Rodale's Organic Life presents a few additional considerations that will help ensure your success in realizing a bountiful broccoli harvest:4
✓ Maintain the garden bed free of weeds and keep the soil loose
✓ When daytime temperatures exceed 75 F (24 C), add a thick layer of organic mulch to conserve moisture and cool the soil
✓ Broccoli must be well watered: Plan to add 1 to 1.5 inches (about 2.5 to 4 cm) of water a week
✓ During dry spells, soak the plants extra well, as a lack of water will result in tough stems
✓ During unseasonably cool weather, you may want to protect your broccoli plants with cloches or row covers
✓ For a spring crop, fast-maturing varieties like Packman are an excellent choice, whereas a slow-maturing variety like Marathon works great in winter in areas where the ground does not freeze
Tips for Preventing Broccoli Pests
While the least affected of all cabbage-family plants, broccoli can be vulnerable to pests.5 Chief among the pests are leaf-eating caterpillars, army worms, cabbageworms and cabbage loopers. Fall crops tend to have fewer problems with these pests than spring ones. Other potential pests include aphids, flea beetles, grasshoppers, harlequin bugs, mites and slugs. The best way to deter pests is to use row covers.
If insect involvement is light, you may be able to get by with inspecting the plants regularly and removing any offending pests by hand. Cabbage-root maggots, which are fly larvae about the size of a grain of rice, like to feed on broccoli roots. While you can easily spot damage by this pest, their presence is generally only noted by the sudden collapse of your plants.
If you've had experience with this pest in the past, your best strategy going forward is to plant your seedlings deeply and press the soil firmly around each stem. You can also prevent adult cabbage-worm maggots from laying their eggs by placing a square of window screen or a lightweight cloth around each broccoli plant.
Important Notes on Harvesting Broccoli
When your plants reach maturity, harvest broccoli heads while the beads in most of the crown are still tight. It's normal to see a slight loosening of florets around the edges. You definitely want to harvest before the florets begin to open and turn yellow.
It's best to cut just below the point where the stems begin to separate. Mother Earth News suggests you cut the stems at an angle to prevent water from pooling inside the stem, where it potentially will cause rot.6 After harvesting the main head, tender side shoots should continue to form along the lower stalk. Continue watering the plant and cutting it, and broccoli will keep producing until the weather turns too hot or too cold.
Maintain harvested broccoli in the refrigerator, where it will last for up to two weeks if stored unwashed. To ensure quality, it is best to steam-blanch broccoli before freezing it. Prior to cooking, you can drive out hidden cabbageworms and cabbage loopers by soaking the broccoli for about 15 minutes in warm water with a little vinegar added.7
If all goes well, you can expect to achieve a yield of 1 pound of broccoli per foot, assuming plants are spaced about 1.5 feet (46 cm) apart.8 That said, three to four plants per person will yield sufficient broccoli for fresh summer eating. If you plan to freeze some of your harvest for later consumption, plan on planting nine to 12 plants per person.
Types of Broccoli You Can Try
The main type of broccoli, featuring the familiar domed head comprising numerous clusters of florets, has a given name of Calabrese, belying broccoli's esteem to the Italians. It is, however, simply referred to as "broccoli." Other broccoli types include:9
- Sprouting varieties: bushier plants producing numerous small heads that do best in mild-winter climates when grown from fall to spring
- Romanesco varieties: large plants requiring plenty of space that produce elegantly-swirled heads comprised of symmetrically-pointed spirals
- Broccoli raab: characterized by fast-growing, immature flower buds that boast a stronger flavor than regular broccoli; popular in Asian and Italian cooking
Broccoli Sprouts: A Faster Route to Broccoli's Many Nutritional Benefits
If you don't have the time or interest to grow broccoli plants, you might want to consider broccoli sprouts. Broccoli sprouts are a nutrient-dense superfood that can be easily cultivated in a glass jar on your kitchen counter. Personally, I grow my sprouts in trays. When grown in soil, you can harvest your sprouts in about a week. I recommend you use organic seeds. As a great addition to salads, smoothies or vegetable juice, broccoli sprouts can radically improve your overall nutrition.
They enable your body to extract more vitamins, minerals, amino acids and essential fats from the rest of your diet. Broccoli sprouts are an excellent alternative particularly if you don't like the smell or taste of broccoli. Fresh broccoli sprouts are far more potent than whole broccoli, allowing you to eat far less in terms of quantity.
A study published by the U.S. National Academy of Sciences10 revealed that three-day-old broccoli sprouts consistently contain anywhere from 10 to 100 times the amount of glucoraphanin — a chemoprotective compound found in mature broccoli.
How to Prepare Broccoli
Ideally, mature broccoli should not be eaten raw. If you prefer raw food, you'd be better off eating raw broccoli sprouts instead of mature broccoli, as they're a far more potent source of sulforaphane.11,12,13 If you're partial to mature broccoli, you can maximize the sulforaphane content by preparing it properly, and combining it with specific foods. Eating broccoli raw will actually only give you about 12 percent of the total sulforaphane content theoretically available.
Research14 shows steaming mature broccoli spears for three to four minutes will increase the available sulforaphane content by eliminating epithiospecifier protein — a heat-sensitive sulfur-grabbing protein that inactivates sulforaphane — while still retaining the enzyme myrosinase, which converts glucoraphanin to sulforaphane. The latter is important, because without myrosinase, you cannot absorb the sulforaphane.
Do not steam the broccoli for more than five minutes, however, as beyond that point, you start losing valuable compounds. If you opt for boiling, blanch it in boiling water for no more than 20 to 30 seconds, then immerse it in cold water to stop the cooking process.
Also, be sure to use raw, freshly harvested broccoli whenever possible. Frozen broccoli has diminished ability to produce sulforaphane as myrosinase15 is quickly destroyed during the blanching process.16 Broccoli can also lose 80 percent of its glucoraphanin — the precursor of sulforaphane — in the first 10 days after harvest.
To increase sulforaphane content even further, eat it with a myrosinase-containing food17 such as mustard seed, daikon radishes, wasabi, arugula or coleslaw. A 2013 study18 that focused on mustard seed — which is said to contain a particularly resilient form of myrosinase — confirmed that mustard seed can boost sulforaphane formation even in boiled broccoli. Adding a myrosinase-rich food is particularly important if you eat the broccoli raw, or use frozen broccoli.