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Kale

Kale, or leaf cabbage, belongs to a group of cabbage cultivars grown for their edible leaves, although some are used as ornamentals. Kale plants have the central leaves do not form a head. Kales are considered to be closer to wild cabbage than most of the many domesticated forms of Brassica oleracea. Kale is grown mainly for autumn and winter harvest, as cold improves its eating quality and flavour; its hardiness permits harvest of fresh greens after most fresh vegetables have become unavailable. The leaves can be eaten fresh or as a cooked vegetable and are a source of vitamin A, vitamin C, calcium, iron, and vitamin B6.



Kale plants produce a rosette of elongated leaves with wavy to frilled margins. The leaves are typically blue-green in colour but can also be light green, red, or purple, depending on the variety. The plant may be harvested by cutting off the entire rosette before the stem has elongated, or (especially in areas with long, cool growing periods) the individual lower leaves may be removed progressively as the main stem elongates. Though usually grown as an annual, kale is a biennial plant and produces yellow four-petaled flowers borne in loose clusters in its second year. The fruits are dry capsules known as siliques.


Table of Contents


Height(Avg)

1 - 3 feet


Width-Circumference (Avg)

1 - 3 feet


Approximate pH

6.0 - 7.5


Types of Kale


There are many kale varieties, and they're all worth a try. The curly-leaf varieties tend to hang on longer in cold weather. But the flat-leaf types generally become established faster. Here are some varieties:


Curly Kale



Undoubtedly the most common type of kale, curly kale has tight, curly edges and a bitter, peppery flavor. The color can range from light-dark green to blue-green leaves to purple colored kale. It is also super versatile, as it can be blanched, boiled, roasted, steamed, or eaten raw.


Lacinato Kale



Lacinato kale, also known as Tuscan, dinosaur kale (or dino kale), Italian kale, black palm, palm, and black kale, has a deep green color, pebbly skin, and soft, flat, elongated leaves. It is native to Italy (with darker varieties called “cavolo nero”), with a much sweeter and milder flavor. The stems are also softer and thinner and can be enjoyed right along with the leaves.


Chinese Kale



Chinese kale, commonly referred to as Chinese broccoli or gai lan, has large, glossy, crisp leaves and a thick stalk. Both the leaves and stalk are completely edible, along with small yellow flowers that are sometimes attached, but the stalks will take longer to cook than the leaves.

Red Russian



Red Russian, sometimes labeled Canadian broccoli, is a purple-stemmed kale with flat, wide leaves and craggly edges. The purple stems are somewhat fibrous, so it’s best to remove them. That being said, the leaves have a mild, sweet, earthy flavor, which makes them a good choice to toss into salads.


Redbor Kale



Redbor is unique in that it is not green but more like a deep purple akin to blueberries. The color is thanks to anthocyanins, antioxidants found in many blue and purple foods. Its flavor is similar to that of cabbage and can be eaten raw and cooked. It’s important to note, however, that while the color will fade with cooking, the mild, sweet flavors will shine through.


Baby Kale



Baby kale is younger leaves that have been harvested before maturity. They are small, tender, light green leaves with a mild, peppery bite similar to baby arugula. Because it has such a sweet flavor compared to mature plants, baby kale is a great way to introduce kale into your diet. Baby kale is best consumed in raw salads.


Siberian Kale



This unique variety stands out from other cultivars because it is technically from the Brassica napus species (rather than Brassica oleracea). This means it is more closely related to turnip greens than to the other varieties we discuss here. As a result, it grows wider flat leaves closer to the ground. The pale green and blue-tinted leaves have ruffled margins and gorgeous white stems. The inner leaf surface is more flattened than other types, making it a great vessel for sauces and seasonings. ‘Siberian’ is the most palatable and mild variety, thanks to its low bitterness and high sweetness.


Ornamental



Ornamental kale is a gardener’s dream and those frilly, colorful, tightly woven bunches you see in many people’s backyards as an ornamental plant. It can range in colors from white, pink, purple, red, and green.


Black Magic



The signature Lacinato-type, ‘Black Magic’ has been a farmer staple for decades. It is a selection of the well-maintained Toscano kale line. This variety is known for its uniformity, dark bluish-green leaves, and beautiful savoyed texture. The tall plants yield elongated, attractive leaves that bunch beautifully together.


Dazzling Blue



The bold purple midribs and blue-green flattened leaves of this Lacinato type stand out stupendously against the rest. ‘Dazzling Blue’ is, well, dazzling! The plants grow very tall and fast, producing a nice variability in leaf shape and coloration.


Bear Necessities



The frilly attractive leaves of this unique kale has the perfect tender lacy texture to enjoy raw in salads or lightly steamed in dishes. ‘Bear Necessities’ takes just 25 days to produce baby leaves and 50 days to full size. The plants are upright, vigorous, and have a beautiful appearance reminiscent of fennel fronds. This cultivar was developed by crossing Russian and Siberian kales with mizuna (a type of serrated mustard).


Simone Broadleaf



Arguably the most beautiful kale population, these seeds produce various colors and types of wavy leaf edges. Some leaves are glazed green, others silvery and light green, and others have purple stems with shades of red. This variety is a beast in the garden and super easy to strip from the stem when used in the kitchen.


Blue Curled Scotch



This heirloom superfood variety has some of the highest antioxidant, anti-inflammatory, and cancer-preventative compounds. This Scotland-native kale has a unique nutty flavor that you can’t find in other types. It is delectably sweet after a light freeze and makes some of the best kale chips you’ve ever tasted.


Scarlet



Ultra-curly leaves add beauty and interest to the garden as well as the plate. This variety holds its reddish tint on top of a blue-green background color, whereas its cousin ‘Redbor’ has a red coloration sprinkled atop a bright green leaf. Either way, the scarlet color intensifies with frosts.


Winterbor



A classic curly type, ‘Winterbor’ is one of the most common commercially grown kales that you find in grocery stores. It has thick blue-green leaves that curl downward and deeply ruffle at the edges, creating ample volume and texture for delicious meals.


Westlandse Winter



Another ultra vigorous curly variety, ‘Westlandse Winter’ is bulky, fast-growing, and extremely dense. It is moderately early and suited for spring, fall, or winter production. These leaves have the most volume of any cultivar and act as the perfect vessel for sauces, oils, and spices. The deep greenish-blue leaves appear like fluffy layered ruffles on 2-foot tall plants.


White Russian



More than just a white-ribbed version of Red Russian kale, this is another selection from Oregon-based Wild Garden Seeds, who crossed Brassica napus ‘red Russian with ‘Siberian’ Kales in the 1980s. This ultra cold-hardy, crisp and sweet flatter-leaved kale has lovely serrated edges and a tender texture for winter salads, soups, and sautees. The frilly margins also add a nice touch to baby kale mixes.


Planting Kale


Kale is a fast-growing vegetable that does best in a planting location with full sun. Plant kale seeds about 1/2 inch deep, leaving at least 1 1/2 to 2 feet between each plant. High nitrogen content in the soil is important for kale to grow its leaves, so adding a few inches of organic matter like compost to a well-draining soil mixture will encourage a healthy harvest.


When to Plant


Kale can be planted three to five weeks prior to your area’s projected last frost date in the spring. In most regions, gardeners can harvest kale in the summer by planting it at this time. It can also be planted in late summer roughly six to eight weeks before your first fall frost.


Those in warm climates (zone 8 and above) can continue to plant in the early fall for a late fall to winter harvest. Kale takes roughly three months to reach maturity from seed, while cuttings will mature in about one month.


Selecting a Planting Site


Kale grows equally well in pots, garden soil, raised garden beds, and other containers. Kale can grow indoors as long as you have adequate lighting. Soil that’s rich in organic matter and has sharp drainage is ideal, and the planting site also should get ample sunlight. Be sure the kale isn't too close to taller plants that will shade it. Growing kale in a window box can also be successful in south- or west-facing windows, but in very hot climates, east-facing windows can help prevent scorching from the afternoon sun.

Spacing, Depth, and Support


Space kale plants roughly 1 1/2 to 2 feet apart, and plant them at the same depth they were growing in their nursery container. Seeds should be planted around 1/2 inch deep. No support structure is necessary.


Growing Kale


How to Grow Kale in Pots


Kale is easy to keep in pots. Not only does this make the plant mobile so that you can move it into adequate sunlight and protect it from severe weather as needed, but it also helps to protect it from garden critters, such as rabbits, that might munch on the leaves. Plus, container growth is ideal if you don’t have garden space or the right soil conditions.


Select a pot with at least a 12-inch diameter. It also should have ample drainage holes. An unglazed clay container is a good option because it will allow excess soil moisture to escape through its walls, helping to prevent root rot. Use a quality potting mix; an organic mix made for growing vegetables is a good option. Transplant your kale into the pot at the same depth it was growing in its previous container, and water it after planting.


How to Grow Kale From Seed


Growing kale from seed can begin inside or outside depending on your region. Kale can be direct seeded in the garden or started indoors and transplanted into the garden. You can direct seed in cold climates as soon as the soil temperature is at least 45 degrees Fahrenheit.

  1. Start plants indoors in a seed-starting mix about six weeks before your last expected frost date. Kale seeds germinate quickly in warm soil and should sprout up within five to eight days.

  2. Cover the seeds with about 1/2 inch of soil, and keep the growing medium moist.

  3. Transplant your seedlings from indoors after the danger of frost has passed.


Kale Care


Light


Kale needs full sun to partial shade in most climates, as the fullest growth will occur when the plant gets six or more hours of direct sunlight on most days. However, if you live in a hot, dry climate, provide your plant with some shade, especially from the strong afternoon sun. Heat can make the leaves wilt and lose their flavor.


Soil


Kale plants like to grow in a rich soil that's high in organic matter with a slightly acidic pH (6.5 to 6.8). The high nitrogen content provided by organic matter is crucial for healthy leaf growth. The soil also should drain well.


Water


Kale needs consistent amount of water to stay healthy, generally growing best in 1 to 1 1/2 inches of water per week. Water your kale plants regularly to keep the soil evenly moist but not soggy. Along with cool temperatures, moist soil helps to keep the kale leaves sweet and crisp, rather than tough and bitter. Mulching around your plants can help to keep the soil cool and to retain moisture.


Temperature and Humidity


The plant is usually considered a cool-weather vegetable and can handle some frost once they're mature. The optimal soil temperature for planting kale is 60 to 65 degrees. All varieties prefer cool temperatures and will be sweetened by a touch of frost. Hot weather turns kale bitter. Kale is a biennial plant, taking two growing seasons (or years) to complete its life cycle, but it's usually grown as an annual. It will collapse if exposed to heavy frosts or snow. But it can be grown throughout the winter, if the winters are mild and there is adequate water.


Fertilizer


When planting, mix fertilizer into the top 3 to 4 inches of soil. Then, feed your kale throughout the growing season, following the instructions on your fertilizer label. Use compost or a high-nitrogen vegetable fertilizer.


Harvesting Kale


Expect to wait approximately two months for your kale plants to mature from seeds. Check the days to maturity on your seed packet or plant label for more precise timing. Spring-planted kale will be good for harvesting throughout the summer months, but it's especially tasty after a light frost.


You can harvest young kale leaves to use fresh in salads or allow your plants to mature for use as a cooked green. Remove the older outer leaves, and allow the center of the plant to continue producing. Kale will keep in the refrigerator, ideally in the crisper drawer, for about a week.


Propagating Kale


Kale is most commonly planted from seeds or nursery plants, but it can also be propagated via cuttings. Kale does regrow after cutting, but it requires a specific propagation process. To pick kale to keep it growing healthy, cuttings must be taken from the oldest leaves. Here’s how:

  1. Use gardening shears to cut a stem from the bottom of the plant on its side, choosing one with multiple leaves from the main stem (do not propagate from the plant's center). Remove the leaves on the lower half of the stem. Trim the bottom of the stem right below a leaf node at a 45-degree angle.

  2. Dip the cut end in rooting hormone.

  3. Plant the bottom half of the stem in a moistened soilless potting mix in a small container with drainage holes.

  4. Continue to keep the growing medium moist. Roots should develop in a few weeks. If you can gently tug on the stem and feel resistance, you’ll know roots have formed. After that, it’s ready for transplanting.


Pests and Plant Diseases


Kale is a member of the cabbage family, which is notorious for attracting insect pests and for rot diseases. Kale is susceptible to black rot and clubroot, as well as aphids, cabbage loopers, cabbageworm, cutworms, flea beetles, and slugs. The best defense is to monitor the plants often for signs of eggs or feeding, such as holes in the leaves. Treat problems as soon as they arise.


Benefits of Kale


Kale is super-rich in antioxidants, vitamins K, A, and C, and other minerals like iron. The antioxidants and other phytonutrients help prevent dangerous ailments like cancer, heart disease, and inflammation. Vitamin K preserves bones while vitamin A enhances vision health. And the antioxidants and vitamin C improve the health of your skin and hair.


Fights Cancer:

The chlorophyll in kale (and other green vegetables) helps prevent the body from absorbing compounds called heterocyclic amines. These are chemicals associated with cancer, which are produced while grilling animal-derived foods at high temperatures. Here’s the trick – the human body can’t absorb much of chlorophyll. So when this chlorophyll binds with the carcinogens, it prevents them from getting absorbed as well. According to the National Cancer Institute, cruciferous vegetables like kale help fight cancer. They also contain substances called glucosinolates, which have a role to play in cancer prevention.

Promotes Heart Health: Kale contains compounds called bile acid sequestrants, which are known to lower blood cholesterol levels. Kale is also exceptionally rich in vitamins C and K (more than spinach) and contains omega-3 fatty acids as well. All of these nutrients are healthy for the heart. They even help lower bad cholesterol and elevate the levels of good cholesterol. The lutein in kale, as per a Los Angeles study, can offer protection against the early stages of atherosclerosis. Another uncommon compound in kale is glucoraphanin, which activates Nrf2, a special reactive protein. This protein creates a coating in your arteries and prevents plaque accumulation.

The potassium in kale helps lower blood pressure levels, which otherwise might lead to a heart attack. The magnesium in the veggie also helps in this aspect. Aids In Diabetes Treatment:

One cup of freshly chopped kale contains about 0.6 grams of fiber, a nutrient that lowers blood glucose levels in patients with type 1 diabetes. Even those with type 2 diabetes can see improved blood sugar levels.

According to a Japanese study, intake of kale can suppress increase in postprandial (after a meal) blood glucose levels.

Fights Inflammation:

This could be the most beneficial property of kale. We know the importance of a balance between omega-3 and omega-6 fatty acids in our body . Kale promotes this balance. It contains both omega-3s and omega-6s at nearly a 1:1 ratio.

These anti-inflammatory properties of kale also make it an ideal food to ease arthritis symptoms. In yet another study, intestinal cells affected by inflammation had shown improvement on exposure to kale and other vegetables from the cabbage family. Offers Antioxidant Benefits:

It could be an understatement when we say kale is packed with antioxidants. In fact, it overflows with ’em. The antioxidants in kale include vitamin C, beta-carotene, and other flavonoids and polyphenols. Other important antioxidants in kale are quercetin and kaempferol. All of these antioxidants neutralize the harmful free radicals, which otherwise can accelerate aging and even lead to serious ailments like cancer and heart disease. The antioxidants in kale can also help boost mood and combat depression.

Aids In Detoxification:

This can be attributed to the fiber in kale. It promotes regularity and helps the body detox. And not just kale, consumption of plants, in general, can aid in detoxification and improve liver health.

Improves Bone Health: Given that kale is rich in potassium, it preserves bone mineral density. Research also suggests a deficiency in vitamin K can be linked to a higher risk of fractures. Kale is wonderfully rich in vitamin K, with one serving offering about 684% of the daily value. The vitamin C in kale also improves bone health – it gives structure to the bones.

We saw kale contains beta-carotene, which is a precursor to vitamin A. The body converts it into vitamin A for use. Vitamin A plays an important role in bone health. However, beware of excess consumption of vitamin A as it has been linked to an increased risk of fractures. Otherwise, beta-carotene is the best form of vitamin A that works great for bone health.

Promotes Digestion:

Kale is high in fiber and water, and both are imperative to proper digestion. They also prevent constipation and enhance the health of the digestive tract. And the B vitamins and vitamin C in kale promote iron absorption – another nutrient that helps release energy from food.

But do consult your doctor before taking kale for treating digestive issues. Certain individuals reported indigestion post kale consumption, which was attributed to its high levels of fiber.

Promotes Vision Health:

According to the Center for Disease Control, kale is one of the foods that can promote vision health. This is because of the presence of lutein and zeaxanthin, two powerful antioxidants for vision health. If the sad part is that these two antioxidants aren’t synthesized in the body, the good part is that kale is rich in them. These two antioxidants help prevent severe eye diseases like age-related macular degeneration and cataracts. Another survey had shown that individuals between the ages of 40 and 59 can cut their risk of macular degeneration by introducing kale (and other such leafy greens) to their diets. Enhances Brain Health:

This is self evident. We don’t have to stress the importance of omega-3s for brain health, and they are present in kale. Also, omega-3s can help lower blood sugar, which otherwise ages the brain cells and deteriorates neuronal health.

And then, we have vitamin K in kale. This nutrient is required for the production of sphingolipids, which are specialized fats responsible for the structure of brain cells. We also have vitamin B6, iron, and folate in kale – all essential for the production of dopamine and serotonin (both of which can help fight depression). So, yes, kale is a brain food. Hence proved.

Again, since kale is rich in folate, it helps in brain development of infants. Eating kale can also help prevent birth defects. It supports the formation of neural tubes and ensures the proper development of the face and heart.

Eliminates Fatigue: Fatigue sure doesn’t feel good. Never. And remember we spoke of a special protein called Nrf2? Well, that can take your fatigue issues by the horns. Kale and other cruciferous veggies contain isothiocyanates, which activate Nrf2. And Nrf2 generates mitochondria, a part of the cells that converts glucose into ATP (a compound in a cell that regulates its energy).

Alright, that’s a little too much of biology. In simple terms – the more mitochondria you have in your system, the better your muscles will work, and the less fatigued you will feel.

Boosts Immune Health:

Good health boils down ultimately to your immune system. If your immune system is strong, your cells are gonna be okay. And if they are okay, you will be okay.

The high levels of vitamin C are what we must look at when we want to boost our immunity levels. And the folate in kale is another immune booster.

Here’s a quick tip – the darker the kale leaves, the more antioxidants it contains (which, in turn, boost your immunity). You can jazz up your salads with dark green kale.

Aids Weight Loss:

It is but a matter of common sense that one needs to consume fewer calories than they expend to lose weight. And eating foods with low calorie density can help in this aspect – which is what kale is. One cup of kale contains just about 33 calories.

Apart from that, the dietary fiber in kale suppresses your appetite and discourages overeating. More importantly, kale is nutrient-dense. If you are on a weight loss diet, you are going to restrict yourself from eating this and that – and this might mean losing on some very important nutrients. With kale on your plate, things are going to be just fine. And yes, the darker the kale, the more the nutrients it has (18). Let’s remember that. Speaking of weight loss, this simple kale recipe can be of help. All you need are 1 sliced banana, 2 cups of chopped kale leaves, ½ cup of plain Greek or almond Greek yogurt, 1 teaspoon honey, and ice cubes (as required). Put them all in a blender and serve. The fiber in banana and kale plays a role in weight loss, and the protein in the yogurt provides long-term satiety. It can keep you full and discourage overeating throughout the day.

Promotes Healthy Pregnancy: The vitamin K keeps the blood vessels strong, and this is particularly important during pregnancy. The added blood flow to the uterine area is quite important, which becomes easier with stronger blood vessels.

And the vitamin C, like we saw, enhances immunity. The nutrient also nourishes the baby inside, and it gives the mother added vitality.

The calcium in kale can ensure your baby can develop strong bones and teeth. However, remember that the calcium found in plants is less bioavailable than that found in dairy products and other fortified foods. So, ensure you also take dairy products (and calcium supplements, after checking with your doctor) during pregnancy.

Also, like we discussed, the folate in kale is quite important during pregnancy. It ensures the baby is healthy and is born without any defects.

Supports Urinary Health:

As kale is rich in calcium, it can help prevent kidney stones and support your urinary health. The calcium binds to the oxalates in the digestive tract and prevents them from getting absorbed. This, otherwise, can lead to calcium oxalate stones.

For quite a while, critics had been shunning kale and accusing it of causing kidney stones. But studies have proven otherwise. Kale is really low in oxalate. So unless you have the ability to eat unreasonable amounts of kale (unless you are the cousin of Gregor, The Mountain, from Game of Thrones), you are safe.

Kale is also rich in iron, another nutrient essential for kidney health. Studies have found that most individuals with kidney disease are also deficient in iron.

Improves Health Of The Skin And Hair:

The vitamin C content in kale helps boost your skin health. The collagen fibers in your skin need vitamin C for strength. Low amounts of vitamin C can weaken your collagen fibers and affect skin health. And since vitamin C also offers antioxidant protection, it sure does save your skin from the harmful UV radiation.

And then, we have vitamin A in kale, the deficiency of which can negatively impact your oil and sweat glands.

Kale, or even kale juice, works well for enhancing skin and hair health. In one study, merely drinking kale juice had improved wrinkles. The juice also acts as a very good skin cleanser. As it detoxifies your skin from within, it, by default, keeps your skin healthy. Washing your face with fresh kale juice in the morning can be a good way to start your day.

Talking about hair, the iron in kale takes care of your tresses. The veggie also takes care of the elasticity of your hair. The iron in kale strengthens your hair while the other nutrients and antioxidants fight dandruff and dry scalp. You can use kale juice to wash your hair before you rinse and then shampoo.

Kale’s omega-3 fatty acids also nourish your hair and give it a healthy texture.


Uses


Kale holds its texture well in cooking, and it can be steamed, stir fried, roasted, or eaten raw. You can turn it into smoothies, kale chips, wilt it into soup, mash it with potatoes or turn it into pesto. Always remove the middle rib as it tends to be overly tough and fibrous and imparts a more bitter taste when eaten. Remove the rib by hand or with kitchen shears.


In Ireland, kale is mixed with mashed potatoes to make the traditional dish colcannon. It is popular on Halloween, when it may be served with sausages. In Sri Lanka, it is known as kola gova or ela gova. It is cultivated for edible use. A dish called 'kale mallung' is served almost everywhere in the island along with rice.


In Italy, cavolo nero kale is an ingredient of the Tuscan soup ribollita. In the Netherlands, a traditional winter dish called "boerenkoolstamppot" is a mix of curly kale and mashed potatoes, sometimes with fried bacon, and served with rookworst ("smoked sausage"). A traditional Portuguese soup, caldo verde, combines pureed potatoes, very finely sliced kale, olive oil and salt.[28] Additional ingredients can include broth and sliced, cooked spicy sausage.

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