Meet the Nutrient Dense Brassicas

By Paula Ogilvie:

The “brassicas” – broccoli, kale, Brussels sprouts, cauliflower, cabbage, collards, and kohlrabi - are closely related members of the mustard family. Also known as the “cole” crops (from the Latin “caulis” meaning stem or stalk), they are all just different species or cultivars of cabbage, Brassica oleracea. Breeding has developed slight differences for each species.

Slice a cabbage vertically and what you see is a short thick stem at the base surrounded by tightly packed leaves. Kale and collard plants have their leaves loosely arranged along their stems. Brussels sprouts are tiny cabbages growing along a tall, thick stem. Each “sprout” is actually a leaf bud.

An older, still common name for the cole group is the “crucifers” (or Crucifereae), which refers to their small, cross-shaped flowers.

With exception of collards, which grow well in the heat of Southern climates, brassicas are cool season crops that grow best when planted in early spring or in late summer for a fall crop as long as they have enough time to mature before a hard freeze arrives. Broccoli and cabbage especially don’t like to bake in summer heat and sun so afternoon shade protection is beneficial. All like our cool nights and intense UV light. The brassicas are good crops for mountain gardens.

Considered some of the healthiest vegetables, they are delicious if prepared correctly. I never liked them growing up because they were usually boiled and over-cooked. It’s no wonder kids of all ages avoided them. But today trendy restaurants offer tasty, roasted Brussel sprouts that are very popular. Sautéing or quickly roasting generally brings out the best flavors. Steaming or boiling can result in over-cooked, soggy vegetables with much of the nutritional benefit lost, so cook for just a few minutes and keep a close eye on them. Broccoli tastes best when it retains its bright green color.

Cole crops are rich in sulfur-containing compounds that impart the distinct flavor and odors that some people may not appreciate. (Remember when President H.W. Bush banned broccoli from Air Force One?) The sulfur compounds break down into smaller units that appear to play a role in cancer prevention. Coles are rich in vitamins C, K, B2, B6, manganese, potassium, copper, dietary fiber, and even protein. They contain chemicals called phenols and flavonoids which have known antioxidant properties and have been shown to reduce cardiovascular diseases. Antioxidants also play a role in reducing chronic inflammation which may be a risk factor for developing cancer. These veggies also appear to be beneficial for those with Type 2 diabetes, (though this may be due to the overall life-style of people who eat healthy foods).

The red and purple colors associated with “super-berries” are known as anthocyanins. Also found in the red-purple varieties of red cabbage, kale, cauliflower, and Brussels sprouts, anthocyanins are important for cardiovascular protection, eye health, and may also reduce inflammation.

Whether large or small, be sure to include some tasty, nutritious brassicas in your cabbage patch. Read seed packet descriptions to learn days to maturity and preferred growing conditions for the many different varieties now available.

BROCCOLI is considered the most nutrient dense of the cole crops. Its heads are actually flower buds. If left too long in the refrigerator (or on the plant) the buds will slowly open into tiny yellow or white flowers. Once the main head is harvested, many smaller side shoots keep developing. Some varieties have been bred or selected for side shoot production. The flowers are good in salads and bees love them too. Broccoli prefers moderately fertile soil with good tilth. Broccoli raab rapini is actually more closely related to turnips, which are a close relative of broccoli. Broccoli raab or “rapini” is thought to have originally grown wild in the Mediterranean and China. It will continually produce smaller new heads if harvested throughout the spring. Once the weather turns hot, the heads quickly flower. With its slightly bitter flavor it is often used in Italian cooking. Broccolini™ looks very similar to Broccoli raab but with longer stems and smaller leaves. It was developed in Japan as a cross between broccoli and Chinese broccoli. It has a mild, sweeter taste, a bit like asparagus. Chinese broccoli is grown for its long flat leaves and thick stems but has smaller heads (florets). It is common in Asian cooking and has a more bitter taste. Broccoli raab and Broccolini look similar, and one of these has self-sown in my garden to my delight. I lightly sauté them in the spring with garlic scapes. Brussels sprouts take a long time to mature. Plant in the spring, but don’t expect any sprouts till fall. Their taste improves after a frost. Both Brussels sprouts and kale produce a type of antifreeze that protects the plant, but all cole crops will sail through light freezes. Cauliflower is a flower head, as the name implies. In cultivation, leaves may be tied around the developing head to keep them white or “blanched”, though some varieties are self-blanching. Newer purple or yellow varieties are generally more nutritious. A heavy feeder that prefers soils with a lot of organic matter, cauliflower only develops one central head and no side shoots. Romanesco Broccoflower is a dramatically beautiful crop with spiraling lime-green florets that taste like a cross between broccoli and cauliflower. Kale is a vigorous plant that’s a moderate feeder. With some compost and a little organic fertilizer a few plants will supply you with greens all summer and fall. Siberian kale has especially tender leaves. Kohlrabi is an above ground stem that swells into an edible vegetable. Sometimes called a stem cabbage, it resembles an alien space ship, and is commonly eaten raw or cooked in many parts of the world. Peel away the two fibrous layers that cover the stem before cooking. The leaves are edible too.

Paula Ogilvie teaches biology and botany at Community College of Denver.

Meet the Nutrient Dense Brassicas

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