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How to Plant, Grow, and Harvest Kale

Lancinato kale, also known as Tuscan kale

Kale is a leafy cool-weather crop that requires two months of cool weather to reach harvest. Kale is a biennial plant, a hardy member of the cabbage family. Kale can grow to 24 inches (60cm) tall; the most common leaf color is green, but kale also comes in shades of blue-green and in variegated shading that range from red to white and yellow to white.

Kale can be eaten raw in salads much as spinach. It can also be chopped and added to soups and stews.

Kale Quick Growing Tips

  • Kale is commonly started indoors and transplanted into the garden when seedlings are 4 to 6 weeks old.
  • Sow seeds indoors or outdoors 4 to 6 weeks before the last frost in spring or as soon as the soil can be worked.
  • Kale yield: plant 4 to 5 plants per household member.

Where to Plant Kale

  • Plant kale in full sun; plant kale in partial shade in warm regions. For optimal flavor, grow kale in cool weather.
  • Plant kale with humus-rich, well-drained soil with a soil pH between 5.5 and 6.8.
Kale seedling
Start kale indoors in late winter for planting out in early spring.

Kale Planting Time

  • Kale is a cool-weather crop that can tolerate temperatures as low as 20°F (-6.7°C). Kale does not tolerate heat.
  • Direct seed or transplant kale so that it comes to harvest before daytime temperatures exceed 80°F (26°C).
  • In cool-summer regions, plant kale in early spring for summer to early fall harvest.
  • In warm- and hot-summer regions, plant kale in late summer for harvest in late fall or winter.
  • In mild-winter regions, kale can be sown in fall for winter harvest.

Planting and Spacing Kale

  • Sow kale seed ½ inch (12mm) deep spaced 3 inches (7cm) apart.
  • Thin plants to 12 inches (30cm) apart when they are 4 to 5 inches (10-12cm) tall.
  • Space rows 18 to 24 inches (45-61cm) apart.
  • Set transplants with crooked stems up to the first leaves.

More tips: Kale Seed Starting Tips.

Curly kale
Curly kale

Watering and Feeding Kale

  • Keep kale well watered for sustained growth and to keep leaves from getting too tough.
  • Add nutrient-rich aged compost to planting beds in advance of planting. Side dress kale with aged compost every 6 weeks.

Kale Companion Plants

  • Good companion plants for kale include beets, celery, herbs, onions, and potatoes.
  • Do not plant kale with pole beans, strawberries, or tomatoes.

Caring for Kale

  • Mound straw around kale once it is 6 inches (15cm) high to prevent plants from touching the soil; soil easily sticks to kale’s often crinkled leaves.

Container Growing Kale

  • Kale will grow in a 6-inch (15cm) container.
  • Plant kale on 8-inch (20cm) centers in large containers.
  • Move kale grown in containers into the cool shade when the weather warms to extend the season.

Kale Pests and Diseases

  • Kale can be attacked by cutworms, cabbage loopers, and imported cabbage worms. Control these pests by handpicking or spry with Bacillus thuringiensis.
  • Kale has no serious disease problems.

Kale harvest

Kale Harvest

  • Kale will be ready for harvest 55 days from transplanting, and 70 to 80 days from seed.
  • Cut individual leaves for use when the plant is 8 to 10 inches high; cut the outside leaves first.
  • If you harvest the entire plant, cut 2 inches above the soil and the plant will sprout new leaves in 1 to 2 weeks.
  • Harvest kale before it gets old and tough.

More tips: How to Harvest and Store Kale.

Storing and Preserving Kale

  • Leave kale in the garden until you are ready to use it. Its flavor will be sweetened by frost.
  • Kale will keep in the refrigerator for 1 to 2 weeks in a plastic bag.
  • Kale can also be frozen, canned, or dried.

Kale Varieties to Grow

  • ‘Blue Armor’ (45-75 days, hybrid); ‘Blue Curled Scotch’ (65 days); ‘Blue Knight’ (55 days, hybrid); ‘Dwarf Blue Curled’ (55 days); ‘Dwarf Blue Scotch’ (55 days); ‘Dwarf Green Curled’ (60 days); ‘Dwarf Siberian’ (65 days); ‘Greenpeace’ (65 days); ‘Hanover Late Seedling’ (68 days); ‘Konserva’ (60 days); ‘Lanciato’ (60-85 days); ‘Red Russian’ (40-60 days); ‘Squire’ (60 days); ‘Verdura’ (60 days); ‘Winterbor’ (60-65 days, hybrid).

About Kale

  • Common name. Kale, borecole
  • Botanical name. Brassica oleracea acephala
  • Origin. Hybrid

More tips: Kale Growing Quick Tips.

Save Money Growing Veggies: KITCHEN GARDEN GROWERS’ GUIDE

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. Harvesttotable.com has more than 10 million visitors each year.

Comments

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  1. Kale greens can be used so many ways in the kitchen that every garden should grow some. Freezing is the best preservation method. Garden Harvest Supply is an excellent source for potted Kale plants.

  2. I will be moving to Thailand and wondered if I could grow Kale there?
    I was thinking maybe in containers inside?
    Your help in this would be greatly appreciated.

    • Kale is a cool temperature crop so it will not thrive in temperatures much above 65F. Temperatures in the 70s will cause kale to bolt and go to seed. You can grow kale indoors if the indoor temperatures remain cool enough. Outdoors try growing baby kale–meaning, harvest when plants are 6 or fewer inches high before the plants mature to the point that they may bolt. In Thailand, you may also want to start growing Asian-origin greens such as mizuna, mibuna, and bok choy.

    • Hi AL I’m about to start a small Aquaponics system with Kale. Please advise me on anything you may have encountered both good and bad with this crop. Thanks and have a great day.

  3. I left my kale in the garden over winter (because last fall and winter were crazy). This spring it is growing again. I cut off the old dead leaves and cut the stalk back to where it was sprouting and I have a new crop! It is putting out small branches with smallish leaves. But already in May it wants to flower.

    • Kale flowering is triggered by warming temperatures. When temperatures rise, the plant prepares to die by first flowering and setting seed to ensure the next generation. You can harvest quickly before the leaves grow bitter–as a result of plant sugars moving to the blossoms. Or you can trim the flowers and wait a few weeks to harvest.

  4. I have tried to start collard and kale seed in my greenhouse t. They sprout just fine but grow to be about 3 inches
    long and spendly What am I doing wrong?

    • Spindly seedlings may be reaching for light. You may need to supplement the natural light with fluorescent lights–14 hours of light each day will be needed. Seedlings need a bit of air circulation and a light breeze for stems to grow stout and not thin. You may want to place a fan in the greenhouse as well.

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