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Kale: Planting, Growing, and Harvesting Kale Plants at Home | The Old Farmer's Almanac

Kale

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Beeldbewerking/GettyImages
Botanical Name
Brassica oleracea var. acephala
Plant Type
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Planting, Growing, and Harvesting Kale

Catherine Boeckmann
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Ever been told to “eat your greens?” Kale is one of the most nutritious vegetables you can grow. It’s crammed with vitamins and powerful antioxidants, and it tastes de-licious. Kale is a hardy cool-season crop which 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 ‘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-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’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 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°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 vegetables 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 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 old blankets propped up by hay bales. Here are a few more season-extending ideas.


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.

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/Disease Type Symptoms Control/Prevention
Aphids Insect Misshapen/yellow leaves; sticky “honeydew” (excrement); sooty, black mold Grow 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 rot Fungus Yellow, V-shape areas on leaf edges that brown and progress toward leaf center; leaves eventually collapse; stem cross sections reveal blackened veins Destroy infected plants; choose resistant varieties; provide good drainage; remove plant debris; rotate crops
Cabbageworms Insect Leaves have large, ragged holes or are skeletonized; heads bored; dark green excrement; yellowish eggs laid singly on leaf undersides Handpick; use row covers; add native plants to invite beneficial insects; grow companion plants (especially thyme); spray Bacillus thuringiensis (Bt)
Flea beetles Insect Numerous tiny holes in leaves Use row covers; mulch heavily; add native plants to invite beneficial insects
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.

Some people dislike kale because it is so crunchy and dry. It sounds odd, but a great way to make kale more tasty is to massage it!

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

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