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How to Grow Kale: Planting, Care, and Harvest Tips for Healthy Greens

kale leaves growing in the garden
Image Credit:
Beeldbewerking/GettyImages
Sponsored Article:
Cummins
Botanical Name
Brassica oleracea var. acephala
Grown as
Biennial
Toxicity
Toxic to Dogs and Cats
Sun Exposure
Full Sun
Partial Sun
Water Needs
Moderate
Height
1–3 feet
Spread
1–3 feet
Soil pH
Neutral
Special Features
Container-Friendly
Low Maintenance
Resilience
Clay Soil Tolerant
Cold Hardy
Plant Type
Vegetables
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Eat your greens—and love them, too! Kale isn’t just a health food trend; it’s a garden superstar. Packed with vitamins and able to handle chilly temps like a champ, kale thrives in spring and fall. 

From curly to dinosaur varieties, this hardy leafy green brings beauty and bounty to your garden—and your plate. Let’s dig into how to grow kale like a pro!

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 ‘Red Russian’ kales; or the nutty and sometimes peppery flavors of Italian kales; or handsome ‘Cavalo Nero’ 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.

Planting

Full sun and fertile, well-draining 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’t 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°F/24°C) or after fall frosts occur. Young plants are not seriously damaged by temperatures down to 25°F/-4°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 starter 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°F/4°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’ll 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 (25–28°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.

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’s productivity.
  • Kale will continue growing until temperatures reach 20°F/-7°C. Do not stop harvesting: A “kiss” 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.

Pests and Problems

Kale Pests and Diseases
Pest/DiseaseTypeSymptomsControl/Prevention
AphidsInsectMisshapen/yellow leaves; sticky “honeydew” (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
Cabbage loopersInsectLarge, ragged holes in leaves from larval feeding; defoliation; stunted or bored heads; excrementHandpick off plants; add native plants to invite beneficial insects; spray larvae with insecticidal soap or Bacillus thuringiensis (Bt)—a natural, bacterial pesticide; use row covers; remove plant debris at end of season
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

Types

  • ‘Red Russian’ (or ‘Russian Red’): heirloom; oak leaf-shape, gray-green leaves with deep-purple veins and stem; an early crop.
  • ‘Lacinato’ (aka ‘Lacinato Blue’, ‘Tuscan’, ‘Black Palm Tree’, or ‘Cavil Nero’): heirloom, straplike leaves up to 2 feet long on plants that resemble small palm trees; heat tolerant and very cold-hardy.
  • ‘True Siberian’: large, frilly, blue-green leaves; cold-hardy; pick all winter in some areas.
  • ‘Vates Blue Curled’: hardy variety that is slow to bolt and does not yellow in cold weather. Its eponymous leaves reach 12 to 14 inches on 15-inch plants.
  • ‘Winterbor’: resembles ‘Vates’, with 24-inch leaves on 2- to 3-foot-tall plants; baby leaves can be harvested at 28 days; frost-tolerant.

Kale varieties

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.

Vegetables

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening, so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Ellen In Asheville</span> Thu, 08/28/2014 - 23:15
I'm still a new gardener, but finishing my first serious season, and I feel like I'm raising more questions than vegetables... The lacinato kale I planted in an 8" deep raised bed (SFG method) last spring is still going well, having survived several barrages of various bugs/worms. The plants look like trees now, with "trunks" where the lower leaves have been harvested, and new leaves continuing to come out the tops. Can it continue through the fall, maybe even into the winter, or would it be better to start another crop? If better to start with new plants now, in late August, should I plant them in a different location? And if so, is there a particularly good fall crop to follow in this space after brassicas? Thanks!
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 08/29/2014 - 12:38

Hi Ellen,

Sounds like you have a wonderful kale crop. If the plants are healthy and growing new leaves there is no need to start new plants. The plants you have are well established and will continue to grow into the winter months.

 <span>Ethan Bob</span> Wed, 08/20/2014 - 23:11
I think i accidently grew kale with kale seeds and the stems are purple and the leaves are green i dont know if its a weed or kale
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 08/21/2014 - 07:34

Hi Ethan, There are so many varieties of kale that any of us might get confused!  Some kale has purple stems (such as Redbor Kale). Here's an interesting page that shows pictures of different kale varieties if that helps! http://ecolocalizer.com/2012/03/25/delicious-nutritious-kale-photo-guide-to-different-varieties/

 <span>Dan Gambardella</span> Tue, 07/08/2014 - 23:15
What can I use to deter pests chewing small holes in the kale leaves?!
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 07/09/2014 - 11:40

The Diamondback moth larva makes small holes in kale leaves. Cabbage worms can also be a problem.B.t. insecticide will control all the cabbage caterpillars.

 <span>Gerard Cunningham</span> Tue, 07/01/2014 - 05:09
this comment section is/and has been so helpful. many of my questions are answered before i ask. thank you.
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 07/01/2014 - 10:41

We are glad you find the information helpful, Gerard. Good luck in the garden!

 <span>Mike 1981</span> Mon, 06/30/2014 - 13:36
Hi. I grew purple kale this year in 15" pots from seedlings picked up at the local nursery. The plants did great until I harvested for the first time. I left a few good leaves on each plant and they've pretty much all wilted and died. The ones with a few robust green leaves still on them only have about an inch of root left. Can these be brought back to life? How? Thx.
<span>Nigel</span> Mon, 05/05/2014 - 13:49
My purple kale in squamish BC has done amazing all winter. now with flowers opening up in top will those flower buds act as seeds? I cut down the stalks but left the stem and roots with a few little growths. I tryed planting the flower buds as seeds. will I have any luck with any of these trials?