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Kale

Brassica oleracea (Acephala group)

A tough, leafy cabbage relative that keeps producing for months if you pick the outer leaves. It's one of the most cold-hardy vegetables and tastes sweeter after frost; in Florida it grows best fall through spring.

Growing facts

Scientific name
Brassica oleracea (Acephala group)
Origin
Eastern Mediterranean
Plant size
1–3 ft rosettes on a thick stem
Growth rate
Medium to fast
Sun
Full sun; tolerates part shade
Soil
Rich, moist soil with compost
Soil pH
6.0–7.5
Pollination
Not needed for leaves
Cold hardiness
Takes hard frost, often into the teens °F; sweeter after it
USDA zones
Cool-season annual in all zones; overwinters in 7–10
Harvest
50–65 days from transplant; baby leaves sooner
When to plant (zones 9–11)
Sep–Feb
When to plant (zones 5–8)
Mar, Apr, Jul, Aug
Water
About every 3 days once established, without rain; more in heat, in pots and while young
Feeding
About every 21 days
Taste
Earthy, slightly bitter and cabbagey; sweeter after cold weather
Nutrition
Very high in vitamins K, A and C, with calcium

Is kale safe to eat? Edible and toxic parts

What you can eat

  • Leaves, raw or cooked
  • Flower shoots, cooked like broccoli rabe

Toxic parts and cautions

  • Take care: Very high in vitamin K. People on warfarin don't need to avoid it, but should eat about the same amount from week to week and tell their doctor about big changes.
  • Good to know: Eating very large amounts of raw kale every day may affect thyroid function in people low in iodine. Normal servings are fine.

Pets: Small amounts of cooked kale are fine for dogs. Large amounts can cause gas and stomach upset.

How to eat and enjoy kale

  • Massaged kale salad
  • Sautéed with garlic and olive oil
  • Kale chips
  • Soups like caldo verde (Portugal) and ribollita (Italy)
  • Smoothies

When it's ripe

Pick the lowest, outer leaves once they're hand-sized, leaving the top growing. Smaller leaves are more tender.

Storing it

Refrigerate unwashed in a bag for up to a week. Blanch and freeze for longer.

Kale varieties (5)

  • Lacinato · also Tuscan kale, Dinosaur kale, Nero di Toscana, Cavolo Nero

    Long, narrow, blue-green leaves with a bumpy texture.

    Origin: Italy (Tuscany) · Taste: Rich, less bitter

    Handles some heat; a good Florida choice.

  • Red Russian

    Flat, frilly gray-green leaves with purple-red stems.

    Taste: Mild, sweet

    Actually Brassica napus. Tender enough for salads.

  • Siberian · also Dwarf Siberian

    A large, frilly-edged kale with blue-green leaves.

    Brassica napus; one of the most cold-hardy.

  • Vates · also Dwarf Blue Curled Vates, Vates Blue Curled Scotch

    A compact, curly blue-green kale.

    Cold-hardy and slow to bolt.

  • Winterbor

    A tall hybrid with thick, tightly curled blue-green leaves.

    Very cold-hardy and productive.

Pests and diseases to watch for

  • Scale insects

    Small bumps, waxy or shell-like, on stems and leaf veins; sticky honeydew and black sooty mold below.

    What to do: Scrub small colonies off with a soft brush.

  • Mealybugs

    White cottony clusters in leaf joints, under leaves and on fruit stems; honeydew and sooty mold.

    What to do: Blast off with a strong spray of water.

  • Aphids

    Clusters of tiny soft insects on new shoots; leaves curl and get sticky.

    What to do: Spray off with water.

  • Sooty mold

    Black, papery film on leaves and fruit that wipes off; it grows on honeydew.

    What to do: Control the insects making honeydew; the mold then weathers away.

  • Spider mites

    Fine pale speckling on leaves, dusty undersides and fine webbing; leaves bronze and drop.

    What to do: Hose the undersides of leaves.

Growing kales? Let Gardyn keep track.

Gardyn tells you when your kale needs water based on your local weather, reminds you to feed and prune in season, and keeps every harvest and photo.

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General guidance, not medical or veterinary advice. Poison Control (US): 1-800-222-1222. ASPCA Animal Poison Control: (888) 426-4435.