蜜桃恋人

How to Grow Kale: The Complete Guide

Photo Credit
Beeldbewerking/GettyImages
Botanical Name
Brassica oleracea var. acephala
Plant Type
Vegetable
Sun Exposure
Full Sun
Part Sun
Soil pH
Neutral to Slightly Alkaline

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Planting, Growing, and Harvesting Kale

Catherine Boeckmann

Ever been told to 鈥渆at your greens?鈥 Kale is one of the most nutritious vegetables you can grow. It鈥檚 crammed with vitamins and powerful antioxidants, and it tastes de-licious. Kale is a hardy cool-season crop that grows best in spring and fall, tolerating frost and even snow. Learn how to plant, grow, and harvest kale. 

About Kale

Kale is a cold-hardy, resilient, non-heading green. It’s one of the easiest members of the brassica family to grow (which includes cabbage, broccoli, brussels sprouts, and other common cole crops.)

A biennial (2-year) plant, kale produces leaves in the first year, and then, in the next year (or sometimes late in the first year), it will form a flower stalk. The stalk forms flowers and then seeds. Once the seeds mature, the plant dies.

Think beyond grocery store kale; there are so many amazing kale flavors and textures to choose from if you grow your own seed: mild, almost salad-like greens, sweet 鈥楻ed Russian鈥 kales, or the nutty and sometimes peppery flavors of Italian kales, or handsome 鈥楥avalo Nero鈥 or Tuscan kale, also called dinosaur kale because of its texture.

As well as being extremely nutritious, kale is attractive, coming in a stunning range of varieties, from bright greens to dark purples, crunchy leaves to crinkled beauties, and everything in between. Its ornamental value can be appreciated in traditional garden beds or containers, especially in the fall.

While easy to grow, there are a few crucial things to get right if you want to enjoy a truly bumper crop of health-boosting leaves. Read on for our guide to growing kale.

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Planting

Full sun and fertile, well-drained soil produce the fastest-growing and most tender leaves, though kale will tolerate partial shade as well. Add plenty of compost to the ground before planting and if your soil isn鈥檛 especially rich, top up its fertility by working in nitrogen-rich amendments such as blood meal, cottonseed meal, or composted manure into the ground before planting.

When to Plant Kale

Kale tastes best when plants grow rapidly and mature before the heat of summer (before temperatures exceed 75掳F/24掳C) or after fall frosts occur. Young plants are not seriously damaged by temperatures down to 25掳F/-4掳C. Mature plants are extremely hardy and can withstand very cold temperatures. However, hot temperatures will slow growth and cause a bitter flavor.

  • For spring: Whether direct seeding into the soil or transplanting start plants from the nursery, you can plant 4 to 6 weeks before the average last spring frost. Seeds will germinate at soil temperatures as low as 40掳F/4掳C.
  • For fall: Select early maturing cultivars and direct-seed 3 months before the first fall frost date. Note: In areas with hot summers, you鈥檒l need to delay sowing until temperatures start to cool off. The cool fall weather really brings out the sweet, nutty flavor of kale which can withstand hard frosts (25鈥28掳F) without experiencing damage. 
  • Kale can also be grown as a winter vegetable under cover or outside in mild winter regions, like the Southwest, Pacific Northwest, and Southeast. They’ll grow and yield all winter long. We suggest speaking to your local cooperative extension to determine if/when you should plant winter vegetables.

How to Plant Kale

  • When planting, add fertilizer (1-1/2 cups of 5-10-10 fertilizer per 25 feet of row) into the top 3 to 4 inches of soil. If you fertilize with compost, apply no more than 1 inch of well-composted organic matter per 100 square feet of garden area.
  • Plant seeds 1/4 to 1/2 of an inch deep, 1 inch apart, in rows 18 to 30 inches apart.
  • If you’re setting out young plants (transplants), plant them at the depth at which they are growing in the container, spaced 12 inches apart, in rows 18 to 30 inches apart.
  • After planting, water the plants well.

See our video for growing perfect kale every time!

Growing

  • After about 2 weeks, thin seedlings to 8 to 12 inches apart.
  • It’s important to keep kale well watered and fertilized. If rain is inconsistent, provide 1 to 1.5 inches of water each week (about 1 gallon per square foot). 
  • Side-dress as needed with a high-nitrogen fertilizer.
  • Mulch the soil to keep down the weeds, retain moisture, and keep kale cool. Kale growth can slow if plants are stressed (too hot or cold, inadequate water, pests or disease). 
  • To guarantee a supply of mature leaves through winter, mulch heavily after the first hard freeze.

Types

  • 鈥楻ed Russian鈥 (or 鈥楻ussian Red鈥):  heirloom; oak leaf-shape, gray-green leaves with deep-purple veins and stem; an early crop
  • 鈥楲acinato鈥 (aka 鈥楲acinato Blue鈥, 鈥楾uscan鈥, 鈥楤lack Palm Tree鈥, or 鈥楥avil Nero鈥): heirloom, straplike leaves up to 2 feet long on plants that resemble small palm trees; heat tolerant and very cold-hardy.
  • 鈥楾rue Siberian鈥: large, frilly, blue-green leaves; cold-hardy; pick all winter in some areas
  • 鈥榁ates Blue Curled鈥: hardy variety that is slow to bolt and does not yellow in cold weather. It eponymous leaves reach 12 to 14 inches on 15-inch plants
  • 鈥榃颈苍迟别谤产辞谤鈥: resembles 鈥榁ates鈥, with 24-inch leaves on 2- to 3-foot-tall plants; baby leaves can be harvested at 28 days; frost-tolerant

Kale varieties

Harvesting

  • Kale is ready to harvest when the leaves are about the size of your hand. Pick about a fistful of outer leaves per harvest, but no more than one-third of the plant at one time.
  • Avoid picking the terminal bud (at the top center of the plant), which helps to maintain the plant鈥檚 productivity.
  • Kale will continue growing until temperatures reach 20掳F/-7掳C. Do not stop harvesting: A 鈥渒iss鈥 of frost makes it even sweeter. (See local frost dates.)
  • To extend the harvest, protect with row covers or tarps. Or, create a makeshift cover of old blankets propped up by hay bales. 
kale in snow
Kale is very cold hardy!
Photo credit: Beeldbewerking/GettyImages

 

How to Store Kale

Store kale, like other leafy greens, in a loose plastic bag in the refrigerator. It should keep for about 1 week.

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Wit and Wisdom

  • Kale is not native to North America. Current varieties are descended from wild cabbage.
  • Farmers have long grown kale as fodder for farm animals, including cattle and sheep.
  • Kale has a number of health benefits, as it is rich in minerals and vitamins A and C.
  • To avoid pest and disease issues, do not plant kale or other cole crops in the same location more than once every 3 or 4 years.
  • The chill of a moderate frost or light snow improves the flavor of kale.

Pests/Diseases

Kale Pests and Diseases
Pest/DiseaseTypeSymptomsControl/Prevention
AphidsInsectMisshapen/yellow leaves; sticky 鈥渉oneydew鈥 (excrement); sooty, black moldGrow companion plants; knock off with water spray; apply insecticidal soap; put banana or orange peels around plants; wipe leaves with a 1 to 2 percent solution of dish soap (no additives) and water every 2 to 3 days for 2 weeks; add native plants to invite beneficial insects
Black rotFungusYellow, V-shape areas on leaf edges that brown and progress toward leaf center; leaves eventually collapse; stem cross sections reveal blackened veinsDestroy infected plants; choose resistant varieties; provide good drainage; remove plant debris; rotate crops
CabbagewormsInsectLeaves have large, ragged holes or are skeletonized; heads bored; dark green excrement; yellowish eggs laid singly on leaf undersidesHandpick; use row covers; add native plants to invite beneficial insects; grow companion plants (especially thyme); spray Bacillus thuringiensis (Bt)
Flea beetlesInsectNumerous tiny holes in leavesUse row covers; mulch heavily; add native plants to invite beneficial insects

Recipes

Potato and Kale Soup
Kale Salad with Cranberries, Feta, and Walnuts
Kale, Sausage, and White Bean Soup
Hearty Kale, Bean, and Zucchini Soup

Cooking Notes

The small, tender leaves can also be added raw to salads or smoothies. Cut and cook the larger leaves like spinach, but be sure to remove the tough ribs before steaming or stir-frying. Kale can also be substituted for spinach in omelets, casseroles, and quesadillas. Enjoy our best kale recipes.

If you find the taste of raw kale to be too bitter, try giving it a massage. Remove stems and then chop leaves into pieces. Add a small amount of lemon juice or olive oil, then use your fingers to rub the leaves together for several minutes until the kale begins to wilt.

Also, kale is great for freezing. See how to freeze kale and other greens.

Vegetables
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it鈥檚 not surprising that she and The Old Farmer鈥檚 蜜桃恋人 found each other. She leads digital content for the 蜜桃恋人 website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Megan P (not verified)

9 years ago

Hi, this was my first year growing kale. Now that we're into the fall season, I'm putting my raised garden to bed for the winter. I pulled out my old tomato stalks and roots, but I'm wondering if I have to do the same with the kale? Thanks in advance for the advice!

Kale is usually treated as an annual, even though it is biennial. When treated as an annual, you can pull up the old stalks and roots, then grow new plants next growing season.

However, depending on your climate, the variety you choose, and how well protected it is over winter, your kale might make it through winter to produce a small harvest in spring before it goes to seed. If you wish to try this, and you live in a cold climate, then cut down any vegetation that has browned and died back, then provide a thick mulch, such as straw, over the kale bed in fall after harvest is over. In spring, uncover the plants when signs of growth emerge.

Yvette (not verified)

9 years 1 month ago

This is my first attempt at growing kale. I see it has some lovely buds. Small. Is this something I should clip or let grow?

If they are leaf buds, leave them be. If they are flower buds, then the plant is starting to bolt (form a flower stalk), which can make the leaves taste bitter. When you see a flower stalk forming, snip it off as soon as possible, to delay the flowering process. (The flowers are edible.) It is a sign that you should harvest the leaves as soon as possible before the flavor becomes too bitter.

Kale is a biennial—setting leaves the first year, and flowering the second year before dying. However, in certain cases, kale can bolt the first year if they are under stress, such as high heat at certain stages, or dry soil.

Srimayi (not verified)

9 years 3 months ago

This is my first year growing kale. Getting a good crop. It started out with a lot of leaf eating insects, but the problem seems to have cleared up. However, I noticed the kale is very bitter. I'm not really enjoying it! It is Toscano Kale. Any tips to reduce bitterness (soil quality?) or is this just how it is? Organic Kale from the store is not so bitter... Thank you!

We're not sure where you live but kale taste bitter if it got too much heat. Kale grows best in cool temperatures (60 to 70掳F. If you live in a hot climate, you could try a spot with partial shade.
Since you've grown the kale, here's another idea to reduce the bitter taste of your kale. When you prepare kale in the kitchen, put the leaves in a bowl. Add a small amount of olive oil and sprinkle of salt and gently rub the kale to break down its tough cellulose structure. This will make the taste more mellow.

Debra Barry (not verified)

9 years 4 months ago

I have never grown kale before but put one in a huge pot on my deck. It is about or foot or more high with large leaves. The tag calls it a dinosaur kale. How do I pick it and keep it growing? The instructions did not say.

Dinosaur kale is also called Tuscan kale, Italian kale, Lacinato kale, or palm tree kale. It usually grows to 2 or 3 feet high. You would harvest it the same as other kale (see the guidelines under "Harvest/Storage" above). Pick the outer, older leaves, cutting each off at the base of the leaf stem where it connects to the main stem. Leave at least 4 to 6 leaves on the plant so that it can make food for itself, and avoid picking the center small leaves, so that the plant will continue to grow. Enjoy!

LorrainePinchevsky (not verified)

9 years 5 months ago

Please help!
I read through the comments but don't have an exact answer on what to do.
my kale plants are 2 ft high.
If you call it a plant. There are only the original bottom 4 leaves then there is a 2 ft stalk in the center with a bunch of white flowers on the top.
Do I cut this off to get more leaves?
Please help.
Thank you

actually it is a little late to cut the flower. it is already finished the vernalization. it will only grow flowers and seeds, even you cut the flower, no more leaves again.
you can keep it and get the seeds. Seed the seeds and keep it from vernalization(low temperature).